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-rw-r--r--compiler/rustc_codegen_gcc/src/debuginfo.rs13
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs3
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/mod.rs53
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm/ffi.rs9
-rw-r--r--compiler/rustc_codegen_ssa/src/mir/analyze.rs4
-rw-r--r--compiler/rustc_codegen_ssa/src/mir/block.rs1
-rw-r--r--compiler/rustc_codegen_ssa/src/mir/debuginfo.rs53
-rw-r--r--compiler/rustc_codegen_ssa/src/mir/operand.rs17
-rw-r--r--compiler/rustc_codegen_ssa/src/mir/statement.rs48
-rw-r--r--compiler/rustc_codegen_ssa/src/traits/debuginfo.rs14
-rw-r--r--compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp1
-rw-r--r--compiler/rustc_middle/src/mir/mod.rs45
-rw-r--r--compiler/rustc_middle/src/mir/pretty.rs22
-rw-r--r--compiler/rustc_middle/src/mir/statement.rs112
-rw-r--r--compiler/rustc_middle/src/mir/terminator.rs8
-rw-r--r--compiler/rustc_middle/src/mir/visit.rs47
-rw-r--r--compiler/rustc_mir_dataflow/src/impls/liveness.rs77
-rw-r--r--compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs4
-rw-r--r--compiler/rustc_mir_transform/src/copy_prop.rs4
-rw-r--r--compiler/rustc_mir_transform/src/coroutine.rs2
-rw-r--r--compiler/rustc_mir_transform/src/dead_store_elimination.rs71
-rw-r--r--compiler/rustc_mir_transform/src/dest_prop.rs4
-rw-r--r--compiler/rustc_mir_transform/src/gvn.rs2
-rw-r--r--compiler/rustc_mir_transform/src/inline.rs8
-rw-r--r--compiler/rustc_mir_transform/src/large_enums.rs2
-rw-r--r--compiler/rustc_mir_transform/src/patch.rs2
-rw-r--r--compiler/rustc_mir_transform/src/promote_consts.rs2
-rw-r--r--compiler/rustc_mir_transform/src/ref_prop.rs2
-rw-r--r--compiler/rustc_mir_transform/src/remove_place_mention.rs2
-rw-r--r--compiler/rustc_mir_transform/src/remove_storage_markers.rs2
-rw-r--r--compiler/rustc_mir_transform/src/remove_zsts.rs2
-rw-r--r--compiler/rustc_mir_transform/src/simplify.rs155
-rw-r--r--compiler/rustc_mir_transform/src/simplify_comparison_integral.rs4
-rw-r--r--compiler/rustc_mir_transform/src/sroa.rs10
-rw-r--r--compiler/rustc_mir_transform/src/strip_debuginfo.rs17
-rw-r--r--tests/codegen-llvm/debug-fndef-size.rs4
-rw-r--r--tests/codegen-llvm/debuginfo-dse.rs362
-rw-r--r--tests/debuginfo/opt/dead_refs.rs50
-rw-r--r--tests/mir-opt/dead-store-elimination/cycle.cycle.DeadStoreElimination-initial.diff4
-rw-r--r--tests/mir-opt/dead-store-elimination/ref.dead_first.DeadStoreElimination-initial.diff30
-rw-r--r--tests/mir-opt/dead-store-elimination/ref.rs31
-rw-r--r--tests/mir-opt/dead-store-elimination/ref.tuple.DeadStoreElimination-initial.diff25
-rw-r--r--tests/mir-opt/debuginfo/simplifycfg.drop_debuginfo.SimplifyCfg-final.diff26
-rw-r--r--tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_1.SimplifyCfg-final.diff30
-rw-r--r--tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_2.SimplifyCfg-final.diff29
-rw-r--r--tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_3.SimplifyCfg-final.diff37
-rw-r--r--tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_identical_succs.SimplifyCfg-final.diff29
-rw-r--r--tests/mir-opt/debuginfo/simplifycfg.rs207
-rw-r--r--tests/mir-opt/inline/inline_shims.drop.Inline.panic-abort.diff2
-rw-r--r--tests/mir-opt/inline/inline_shims.drop.Inline.panic-unwind.diff2
-rw-r--r--tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff15
-rw-r--r--tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff15
-rw-r--r--tests/mir-opt/issue_101973.inner.GVN.panic-abort.diff1
-rw-r--r--tests/mir-opt/issue_101973.inner.GVN.panic-unwind.diff1
-rw-r--r--tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-abort.diff12
-rw-r--r--tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-unwind.diff12
-rw-r--r--tests/mir-opt/pre-codegen/clone_as_copy.clone_as_copy.PreCodegen.after.mir4
-rw-r--r--tests/mir-opt/pre-codegen/clone_as_copy.enum_clone_as_copy.PreCodegen.after.mir46
-rw-r--r--tests/mir-opt/pre-codegen/clone_as_copy.rs16
-rw-r--r--tests/mir-opt/pre-codegen/dead_on_invalid_place.invalid_place.PreCodegen.after.mir13
-rw-r--r--tests/mir-opt/pre-codegen/dead_on_invalid_place.rs27
-rw-r--r--tests/mir-opt/pre-codegen/loops.filter_mapped.PreCodegen.after.mir44
-rw-r--r--tests/mir-opt/pre-codegen/loops.int_range.PreCodegen.after.mir94
-rw-r--r--tests/mir-opt/pre-codegen/loops.mapped.PreCodegen.after.mir84
-rw-r--r--tests/mir-opt/pre-codegen/loops.rs1
-rw-r--r--tests/mir-opt/pre-codegen/loops.vec_move.PreCodegen.after.mir306
-rw-r--r--tests/mir-opt/pre-codegen/slice_filter.variant_a-{closure#0}.PreCodegen.after.mir205
-rw-r--r--tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-abort.mir211
-rw-r--r--tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-unwind.mir219
-rw-r--r--tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-abort.mir177
-rw-r--r--tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-unwind.mir177
-rw-r--r--tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-abort.mir2
-rw-r--r--tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-unwind.mir2
-rw-r--r--tests/ui/extern/extern-types-field-offset.rs5
74 files changed, 2798 insertions, 581 deletions
diff --git a/compiler/rustc_codegen_gcc/src/debuginfo.rs b/compiler/rustc_codegen_gcc/src/debuginfo.rs
index 4c8585192a1..0f015cc23f5 100644
--- a/compiler/rustc_codegen_gcc/src/debuginfo.rs
+++ b/compiler/rustc_codegen_gcc/src/debuginfo.rs
@@ -29,13 +29,24 @@ impl<'a, 'gcc, 'tcx> DebugInfoBuilderMethods for Builder<'a, 'gcc, 'tcx> {
         _variable_alloca: Self::Value,
         _direct_offset: Size,
         _indirect_offsets: &[Size],
-        _fragment: Option<Range<Size>>,
+        _fragment: &Option<Range<Size>>,
     ) {
         // FIXME(tempdragon): Not sure if this is correct, probably wrong but still keep it here.
         #[cfg(feature = "master")]
         _variable_alloca.set_location(_dbg_loc);
     }
 
+    fn dbg_var_value(
+        &mut self,
+        _dbg_var: Self::DIVariable,
+        _dbg_loc: Self::DILocation,
+        _value: Self::Value,
+        _direct_offset: Size,
+        _indirect_offsets: &[Size],
+        _fragment: &Option<Range<Size>>,
+    ) {
+    }
+
     fn insert_reference_to_gdb_debug_scripts_section_global(&mut self) {
         // TODO(antoyo): insert reference to gdb debug scripts section global.
     }
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs b/compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs
index 40842915222..52d04625749 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs
@@ -35,3 +35,6 @@ declare_constant!(DW_OP_plus_uconst: u64);
 /// Double-checked by a static assertion in `RustWrapper.cpp`.
 #[allow(non_upper_case_globals)]
 pub(crate) const DW_OP_LLVM_fragment: u64 = 0x1000;
+// It describes the actual value of a source variable which might not exist in registers or in memory.
+#[allow(non_upper_case_globals)]
+pub(crate) const DW_OP_stack_value: u64 = 0x9f;
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
index af64e4ebed0..c6ad1c2e18e 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
@@ -156,7 +156,7 @@ impl<'ll> DebugInfoBuilderMethods for Builder<'_, 'll, '_> {
         variable_alloca: Self::Value,
         direct_offset: Size,
         indirect_offsets: &[Size],
-        fragment: Option<Range<Size>>,
+        fragment: &Option<Range<Size>>,
     ) {
         use dwarf_const::{DW_OP_LLVM_fragment, DW_OP_deref, DW_OP_plus_uconst};
 
@@ -187,7 +187,6 @@ impl<'ll> DebugInfoBuilderMethods for Builder<'_, 'll, '_> {
             llvm::LLVMDIBuilderCreateExpression(di_builder, addr_ops.as_ptr(), addr_ops.len())
         };
         unsafe {
-            // FIXME(eddyb) replace `llvm.dbg.declare` with `llvm.dbg.addr`.
             llvm::LLVMDIBuilderInsertDeclareRecordAtEnd(
                 di_builder,
                 variable_alloca,
@@ -199,6 +198,56 @@ impl<'ll> DebugInfoBuilderMethods for Builder<'_, 'll, '_> {
         };
     }
 
+    fn dbg_var_value(
+        &mut self,
+        dbg_var: &'ll DIVariable,
+        dbg_loc: &'ll DILocation,
+        value: Self::Value,
+        direct_offset: Size,
+        indirect_offsets: &[Size],
+        fragment: &Option<Range<Size>>,
+    ) {
+        use dwarf_const::{DW_OP_LLVM_fragment, DW_OP_deref, DW_OP_plus_uconst, DW_OP_stack_value};
+
+        // Convert the direct and indirect offsets and fragment byte range to address ops.
+        let mut addr_ops = SmallVec::<[u64; 8]>::new();
+
+        if direct_offset.bytes() > 0 {
+            addr_ops.push(DW_OP_plus_uconst);
+            addr_ops.push(direct_offset.bytes() as u64);
+            addr_ops.push(DW_OP_stack_value);
+        }
+        for &offset in indirect_offsets {
+            addr_ops.push(DW_OP_deref);
+            if offset.bytes() > 0 {
+                addr_ops.push(DW_OP_plus_uconst);
+                addr_ops.push(offset.bytes() as u64);
+            }
+        }
+        if let Some(fragment) = fragment {
+            // `DW_OP_LLVM_fragment` takes as arguments the fragment's
+            // offset and size, both of them in bits.
+            addr_ops.push(DW_OP_LLVM_fragment);
+            addr_ops.push(fragment.start.bits() as u64);
+            addr_ops.push((fragment.end - fragment.start).bits() as u64);
+        }
+
+        let di_builder = DIB(self.cx());
+        let addr_expr = unsafe {
+            llvm::LLVMDIBuilderCreateExpression(di_builder, addr_ops.as_ptr(), addr_ops.len())
+        };
+        unsafe {
+            llvm::LLVMDIBuilderInsertDbgValueRecordAtEnd(
+                di_builder,
+                value,
+                dbg_var,
+                addr_expr,
+                dbg_loc,
+                self.llbb(),
+            );
+        }
+    }
+
     fn set_dbg_loc(&mut self, dbg_loc: &'ll DILocation) {
         unsafe {
             llvm::LLVMSetCurrentDebugLocation2(self.llbuilder, dbg_loc);
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index e9f92267a7d..7fbba029407 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1991,6 +1991,15 @@ unsafe extern "C" {
         Block: &'ll BasicBlock,
     ) -> &'ll DbgRecord;
 
+    pub(crate) fn LLVMDIBuilderInsertDbgValueRecordAtEnd<'ll>(
+        Builder: &DIBuilder<'ll>,
+        Val: &'ll Value,
+        VarInfo: &'ll Metadata,
+        Expr: &'ll Metadata,
+        DebugLoc: &'ll Metadata,
+        Block: &'ll BasicBlock,
+    ) -> &'ll DbgRecord;
+
     pub(crate) fn LLVMDIBuilderCreateAutoVariable<'ll>(
         Builder: &DIBuilder<'ll>,
         Scope: &'ll Metadata,
diff --git a/compiler/rustc_codegen_ssa/src/mir/analyze.rs b/compiler/rustc_codegen_ssa/src/mir/analyze.rs
index 45bc5451946..0a37a904193 100644
--- a/compiler/rustc_codegen_ssa/src/mir/analyze.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/analyze.rs
@@ -260,6 +260,10 @@ impl<'a, 'b, 'tcx, Bx: BuilderMethods<'b, 'tcx>> Visitor<'tcx> for LocalAnalyzer
             PlaceContext::MutatingUse(MutatingUseContext::Yield) => bug!(),
         }
     }
+
+    fn visit_statement_debuginfo(&mut self, _: &mir::StmtDebugInfo<'tcx>, _: Location) {
+        // Debuginfo does not generate actual code.
+    }
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index b2dc4fe32b0..e371f1a7623 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -1320,6 +1320,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             for statement in &data.statements {
                 self.codegen_statement(bx, statement);
             }
+            self.codegen_stmt_debuginfos(bx, &data.after_last_stmt_debuginfos);
 
             let merging_succ = self.codegen_terminator(bx, bb, data.terminator());
             if let MergingSucc::False = merging_succ {
diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
index b8f635ab781..0c9acf087f9 100644
--- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
@@ -253,6 +253,53 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         spill_slot
     }
 
+    // Indicates that local is set to a new value. The `layout` and `projection` are used to
+    // calculate the offset.
+    pub(crate) fn debug_new_val_to_local(
+        &self,
+        bx: &mut Bx,
+        local: mir::Local,
+        base: PlaceRef<'tcx, Bx::Value>,
+        projection: &[mir::PlaceElem<'tcx>],
+    ) {
+        let full_debug_info = bx.sess().opts.debuginfo == DebugInfo::Full;
+        if !full_debug_info {
+            return;
+        }
+
+        let vars = match &self.per_local_var_debug_info {
+            Some(per_local) => &per_local[local],
+            None => return,
+        };
+
+        let DebugInfoOffset { direct_offset, indirect_offsets, result: _ } =
+            calculate_debuginfo_offset(bx, projection, base.layout);
+        for var in vars.iter() {
+            let Some(dbg_var) = var.dbg_var else {
+                continue;
+            };
+            let Some(dbg_loc) = self.dbg_loc(var.source_info) else {
+                continue;
+            };
+            bx.dbg_var_value(
+                dbg_var,
+                dbg_loc,
+                base.val.llval,
+                direct_offset,
+                &indirect_offsets,
+                &var.fragment,
+            );
+        }
+    }
+
+    pub(crate) fn debug_poison_to_local(&self, bx: &mut Bx, local: mir::Local) {
+        let ty = self.monomorphize(self.mir.local_decls[local].ty);
+        let layout = bx.cx().layout_of(ty);
+        let to_backend_ty = bx.cx().immediate_backend_type(layout);
+        let place_ref = PlaceRef::new_sized(bx.cx().const_poison(to_backend_ty), layout);
+        self.debug_new_val_to_local(bx, local, place_ref, &[]);
+    }
+
     /// Apply debuginfo and/or name, after creating the `alloca` for a local,
     /// or initializing the local with an operand (whichever applies).
     pub(crate) fn debug_introduce_local(&self, bx: &mut Bx, local: mir::Local) {
@@ -424,7 +471,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 alloca.val.llval,
                 Size::ZERO,
                 &[Size::ZERO],
-                var.fragment,
+                &var.fragment,
             );
         } else {
             bx.dbg_var_addr(
@@ -433,7 +480,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 base.val.llval,
                 direct_offset,
                 &indirect_offsets,
-                var.fragment,
+                &var.fragment,
             );
         }
     }
@@ -455,7 +502,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 let base = FunctionCx::spill_operand_to_stack(operand, Some(name), bx);
                 bx.clear_dbg_loc();
 
-                bx.dbg_var_addr(dbg_var, dbg_loc, base.val.llval, Size::ZERO, &[], fragment);
+                bx.dbg_var_addr(dbg_var, dbg_loc, base.val.llval, Size::ZERO, &[], &fragment);
             }
         }
     }
diff --git a/compiler/rustc_codegen_ssa/src/mir/operand.rs b/compiler/rustc_codegen_ssa/src/mir/operand.rs
index 5f7f87fc692..88a8e2a844c 100644
--- a/compiler/rustc_codegen_ssa/src/mir/operand.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/operand.rs
@@ -71,16 +71,23 @@ pub enum OperandValue<V> {
 }
 
 impl<V: CodegenObject> OperandValue<V> {
+    /// Return the data pointer and optional metadata as backend values
+    /// if this value can be treat as a pointer.
+    pub(crate) fn try_pointer_parts(self) -> Option<(V, Option<V>)> {
+        match self {
+            OperandValue::Immediate(llptr) => Some((llptr, None)),
+            OperandValue::Pair(llptr, llextra) => Some((llptr, Some(llextra))),
+            OperandValue::Ref(_) | OperandValue::ZeroSized => None,
+        }
+    }
+
     /// Treat this value as a pointer and return the data pointer and
     /// optional metadata as backend values.
     ///
     /// If you're making a place, use [`Self::deref`] instead.
     pub(crate) fn pointer_parts(self) -> (V, Option<V>) {
-        match self {
-            OperandValue::Immediate(llptr) => (llptr, None),
-            OperandValue::Pair(llptr, llextra) => (llptr, Some(llextra)),
-            _ => bug!("OperandValue cannot be a pointer: {self:?}"),
-        }
+        self.try_pointer_parts()
+            .unwrap_or_else(|| bug!("OperandValue cannot be a pointer: {self:?}"))
     }
 
     /// Treat this value as a pointer and return the place to which it points.
diff --git a/compiler/rustc_codegen_ssa/src/mir/statement.rs b/compiler/rustc_codegen_ssa/src/mir/statement.rs
index 0a50d7f18db..88590b6271b 100644
--- a/compiler/rustc_codegen_ssa/src/mir/statement.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/statement.rs
@@ -1,4 +1,4 @@
-use rustc_middle::mir::{self, NonDivergingIntrinsic};
+use rustc_middle::mir::{self, NonDivergingIntrinsic, StmtDebugInfo};
 use rustc_middle::span_bug;
 use tracing::instrument;
 
@@ -8,6 +8,7 @@ use crate::traits::*;
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     #[instrument(level = "debug", skip(self, bx))]
     pub(crate) fn codegen_statement(&mut self, bx: &mut Bx, statement: &mir::Statement<'tcx>) {
+        self.codegen_stmt_debuginfos(bx, &statement.debuginfos);
         self.set_debug_loc(bx, statement.source_info);
         match statement.kind {
             mir::StatementKind::Assign(box (ref place, ref rvalue)) => {
@@ -101,4 +102,49 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             | mir::StatementKind::Nop => {}
         }
     }
+
+    pub(crate) fn codegen_stmt_debuginfo(&mut self, bx: &mut Bx, debuginfo: &StmtDebugInfo<'tcx>) {
+        match debuginfo {
+            StmtDebugInfo::AssignRef(dest, place) => {
+                let local_ref = match self.locals[place.local] {
+                    // For an rvalue like `&(_1.1)`, when `BackendRepr` is `BackendRepr::Memory`, we allocate a block of memory to this place.
+                    // The place is an indirect pointer, we can refer to it directly.
+                    LocalRef::Place(place_ref) => Some((place_ref, place.projection.as_slice())),
+                    // For an rvalue like `&((*_1).1)`, we are calculating the address of `_1.1`.
+                    // The deref projection is no-op here.
+                    LocalRef::Operand(operand_ref) if place.is_indirect_first_projection() => {
+                        Some((operand_ref.deref(bx.cx()), &place.projection[1..]))
+                    }
+                    // For an rvalue like `&1`, when `BackendRepr` is `BackendRepr::Scalar`,
+                    // we cannot get the address.
+                    // N.B. `non_ssa_locals` returns that this is an SSA local.
+                    LocalRef::Operand(_) => None,
+                    LocalRef::UnsizedPlace(_) | LocalRef::PendingOperand => None,
+                }
+                .filter(|(_, projection)| {
+                    // Drop unsupported projections.
+                    projection.iter().all(|p| p.can_use_in_debuginfo())
+                });
+                if let Some((base, projection)) = local_ref {
+                    self.debug_new_val_to_local(bx, *dest, base, projection);
+                } else {
+                    // If the address cannot be calculated, use poison to indicate that the value has been optimized out.
+                    self.debug_poison_to_local(bx, *dest);
+                }
+            }
+            StmtDebugInfo::InvalidAssign(local) => {
+                self.debug_poison_to_local(bx, *local);
+            }
+        }
+    }
+
+    pub(crate) fn codegen_stmt_debuginfos(
+        &mut self,
+        bx: &mut Bx,
+        debuginfos: &[StmtDebugInfo<'tcx>],
+    ) {
+        for debuginfo in debuginfos {
+            self.codegen_stmt_debuginfo(bx, debuginfo);
+        }
+    }
 }
diff --git a/compiler/rustc_codegen_ssa/src/traits/debuginfo.rs b/compiler/rustc_codegen_ssa/src/traits/debuginfo.rs
index b9d4950e0ad..a4da6c915de 100644
--- a/compiler/rustc_codegen_ssa/src/traits/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/debuginfo.rs
@@ -77,7 +77,19 @@ pub trait DebugInfoBuilderMethods: BackendTypes {
         indirect_offsets: &[Size],
         // Byte range in the `dbg_var` covered by this fragment,
         // if this is a fragment of a composite `DIVariable`.
-        fragment: Option<Range<Size>>,
+        fragment: &Option<Range<Size>>,
+    );
+    fn dbg_var_value(
+        &mut self,
+        dbg_var: Self::DIVariable,
+        dbg_loc: Self::DILocation,
+        value: Self::Value,
+        direct_offset: Size,
+        // NB: each offset implies a deref (i.e. they're steps in a pointer chain).
+        indirect_offsets: &[Size],
+        // Byte range in the `dbg_var` covered by this fragment,
+        // if this is a fragment of a composite `DIVariable`.
+        fragment: &Option<Range<Size>>,
     );
     fn set_dbg_loc(&mut self, dbg_loc: Self::DILocation);
     fn clear_dbg_loc(&mut self);
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 2b83ea24ac6..e38474f09ff 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -58,6 +58,7 @@ using namespace llvm::object;
 // This opcode is an LLVM detail that could hypothetically change (?), so
 // verify that the hard-coded value in `dwarf_const.rs` still agrees with LLVM.
 static_assert(dwarf::DW_OP_LLVM_fragment == 0x1000);
+static_assert(dwarf::DW_OP_stack_value == 0x9f);
 
 // LLVMAtomicOrdering is already an enum - don't create another
 // one.
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 28142382b13..8eb7aa71fcd 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -1298,6 +1298,10 @@ pub struct BasicBlockData<'tcx> {
     /// List of statements in this block.
     pub statements: Vec<Statement<'tcx>>,
 
+    /// All debuginfos happen before the statement.
+    /// Put debuginfos here when the last statement is eliminated.
+    pub after_last_stmt_debuginfos: StmtDebugInfos<'tcx>,
+
     /// Terminator for this block.
     ///
     /// N.B., this should generally ONLY be `None` during construction.
@@ -1325,7 +1329,12 @@ impl<'tcx> BasicBlockData<'tcx> {
         terminator: Option<Terminator<'tcx>>,
         is_cleanup: bool,
     ) -> BasicBlockData<'tcx> {
-        BasicBlockData { statements, terminator, is_cleanup }
+        BasicBlockData {
+            statements,
+            after_last_stmt_debuginfos: StmtDebugInfos::default(),
+            terminator,
+            is_cleanup,
+        }
     }
 
     /// Accessor for terminator.
@@ -1360,6 +1369,36 @@ impl<'tcx> BasicBlockData<'tcx> {
             self.terminator().successors()
         }
     }
+
+    pub fn retain_statements<F>(&mut self, mut f: F)
+    where
+        F: FnMut(&Statement<'tcx>) -> bool,
+    {
+        // Place debuginfos into the next retained statement,
+        // this `debuginfos` variable is used to cache debuginfos between two retained statements.
+        let mut debuginfos = StmtDebugInfos::default();
+        self.statements.retain_mut(|stmt| {
+            let retain = f(stmt);
+            if retain {
+                stmt.debuginfos.prepend(&mut debuginfos);
+            } else {
+                debuginfos.append(&mut stmt.debuginfos);
+            }
+            retain
+        });
+        self.after_last_stmt_debuginfos.prepend(&mut debuginfos);
+    }
+
+    pub fn strip_nops(&mut self) {
+        self.retain_statements(|stmt| !matches!(stmt.kind, StatementKind::Nop))
+    }
+
+    pub fn drop_debuginfo(&mut self) {
+        self.after_last_stmt_debuginfos.drop_debuginfo();
+        for stmt in self.statements.iter_mut() {
+            stmt.debuginfos.drop_debuginfo();
+        }
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////
@@ -1664,10 +1703,10 @@ mod size_asserts {
 
     use super::*;
     // tidy-alphabetical-start
-    static_assert_size!(BasicBlockData<'_>, 128);
+    static_assert_size!(BasicBlockData<'_>, 152);
     static_assert_size!(LocalDecl<'_>, 40);
     static_assert_size!(SourceScopeData<'_>, 64);
-    static_assert_size!(Statement<'_>, 32);
+    static_assert_size!(Statement<'_>, 56);
     static_assert_size!(Terminator<'_>, 96);
     static_assert_size!(VarDebugInfo<'_>, 88);
     // tidy-alphabetical-end
diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
index 350d75c2ee7..d87e3abe3b2 100644
--- a/compiler/rustc_middle/src/mir/pretty.rs
+++ b/compiler/rustc_middle/src/mir/pretty.rs
@@ -719,6 +719,11 @@ impl<'de, 'tcx> MirWriter<'de, 'tcx> {
         let mut current_location = Location { block, statement_index: 0 };
         for statement in &data.statements {
             (self.extra_data)(PassWhere::BeforeLocation(current_location), w)?;
+
+            for debuginfo in statement.debuginfos.iter() {
+                writeln!(w, "{INDENT}{INDENT}// DBG: {debuginfo:?};")?;
+            }
+
             let indented_body = format!("{INDENT}{INDENT}{statement:?};");
             if self.options.include_extra_comments {
                 writeln!(
@@ -749,6 +754,10 @@ impl<'de, 'tcx> MirWriter<'de, 'tcx> {
             current_location.statement_index += 1;
         }
 
+        for debuginfo in data.after_last_stmt_debuginfos.iter() {
+            writeln!(w, "{INDENT}{INDENT}// DBG: {debuginfo:?};")?;
+        }
+
         // Terminator at the bottom.
         (self.extra_data)(PassWhere::BeforeLocation(current_location), w)?;
         if data.terminator.is_some() {
@@ -829,6 +838,19 @@ impl Debug for Statement<'_> {
     }
 }
 
+impl Debug for StmtDebugInfo<'_> {
+    fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
+        match self {
+            StmtDebugInfo::AssignRef(local, place) => {
+                write!(fmt, "{local:?} = &{place:?}")
+            }
+            StmtDebugInfo::InvalidAssign(local) => {
+                write!(fmt, "{local:?} = &?")
+            }
+        }
+    }
+}
+
 impl Display for NonDivergingIntrinsic<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
diff --git a/compiler/rustc_middle/src/mir/statement.rs b/compiler/rustc_middle/src/mir/statement.rs
index e009fe05b53..f310e1e5762 100644
--- a/compiler/rustc_middle/src/mir/statement.rs
+++ b/compiler/rustc_middle/src/mir/statement.rs
@@ -1,5 +1,7 @@
 //! Functionality for statements, operands, places, and things that appear in them.
 
+use std::ops;
+
 use tracing::{debug, instrument};
 
 use super::interpret::GlobalAlloc;
@@ -15,17 +17,28 @@ use crate::ty::CoroutineArgsExt;
 pub struct Statement<'tcx> {
     pub source_info: SourceInfo,
     pub kind: StatementKind<'tcx>,
+    /// Some debuginfos appearing before the primary statement.
+    pub debuginfos: StmtDebugInfos<'tcx>,
 }
 
 impl<'tcx> Statement<'tcx> {
     /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
     /// invalidating statement indices in `Location`s.
-    pub fn make_nop(&mut self) {
-        self.kind = StatementKind::Nop
+    pub fn make_nop(&mut self, drop_debuginfo: bool) {
+        if matches!(self.kind, StatementKind::Nop) {
+            return;
+        }
+        let replaced_stmt = std::mem::replace(&mut self.kind, StatementKind::Nop);
+        if !drop_debuginfo {
+            let Some(debuginfo) = replaced_stmt.as_debuginfo() else {
+                bug!("debuginfo is not yet supported.")
+            };
+            self.debuginfos.push(debuginfo);
+        }
     }
 
     pub fn new(source_info: SourceInfo, kind: StatementKind<'tcx>) -> Self {
-        Statement { source_info, kind }
+        Statement { source_info, kind, debuginfos: StmtDebugInfos::default() }
     }
 }
 
@@ -63,6 +76,17 @@ impl<'tcx> StatementKind<'tcx> {
             _ => None,
         }
     }
+
+    pub fn as_debuginfo(&self) -> Option<StmtDebugInfo<'tcx>> {
+        match self {
+            StatementKind::Assign(box (place, Rvalue::Ref(_, _, ref_place)))
+                if let Some(local) = place.as_local() =>
+            {
+                Some(StmtDebugInfo::AssignRef(local, *ref_place))
+            }
+            _ => None,
+        }
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////
@@ -503,6 +527,20 @@ impl<'tcx> PlaceRef<'tcx> {
         })
     }
 
+    /// Return the place accessed locals that include the base local.
+    pub fn accessed_locals(self) -> impl Iterator<Item = Local> {
+        std::iter::once(self.local).chain(self.projection.iter().filter_map(|proj| match proj {
+            ProjectionElem::Index(local) => Some(*local),
+            ProjectionElem::Deref
+            | ProjectionElem::Field(_, _)
+            | ProjectionElem::ConstantIndex { .. }
+            | ProjectionElem::Subslice { .. }
+            | ProjectionElem::Downcast(_, _)
+            | ProjectionElem::OpaqueCast(_)
+            | ProjectionElem::UnwrapUnsafeBinder(_) => None,
+        }))
+    }
+
     /// Generates a new place by appending `more_projections` to the existing ones
     /// and interning the result.
     pub fn project_deeper(
@@ -967,3 +1005,71 @@ impl RawPtrKind {
         }
     }
 }
+
+#[derive(Default, Debug, Clone, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
+pub struct StmtDebugInfos<'tcx>(Vec<StmtDebugInfo<'tcx>>);
+
+impl<'tcx> StmtDebugInfos<'tcx> {
+    pub fn push(&mut self, debuginfo: StmtDebugInfo<'tcx>) {
+        self.0.push(debuginfo);
+    }
+
+    pub fn drop_debuginfo(&mut self) {
+        self.0.clear();
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
+
+    pub fn prepend(&mut self, debuginfos: &mut Self) {
+        if debuginfos.is_empty() {
+            return;
+        };
+        debuginfos.0.append(self);
+        std::mem::swap(debuginfos, self);
+    }
+
+    pub fn append(&mut self, debuginfos: &mut Self) {
+        if debuginfos.is_empty() {
+            return;
+        };
+        self.0.append(debuginfos);
+    }
+
+    pub fn extend(&mut self, debuginfos: &Self) {
+        if debuginfos.is_empty() {
+            return;
+        };
+        self.0.extend_from_slice(debuginfos);
+    }
+
+    pub fn retain<F>(&mut self, f: F)
+    where
+        F: FnMut(&StmtDebugInfo<'tcx>) -> bool,
+    {
+        self.0.retain(f);
+    }
+}
+
+impl<'tcx> ops::Deref for StmtDebugInfos<'tcx> {
+    type Target = Vec<StmtDebugInfo<'tcx>>;
+
+    #[inline]
+    fn deref(&self) -> &Vec<StmtDebugInfo<'tcx>> {
+        &self.0
+    }
+}
+
+impl<'tcx> ops::DerefMut for StmtDebugInfos<'tcx> {
+    #[inline]
+    fn deref_mut(&mut self) -> &mut Vec<StmtDebugInfo<'tcx>> {
+        &mut self.0
+    }
+}
+
+#[derive(Clone, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
+pub enum StmtDebugInfo<'tcx> {
+    AssignRef(Local, Place<'tcx>),
+    InvalidAssign(Local),
+}
diff --git a/compiler/rustc_middle/src/mir/terminator.rs b/compiler/rustc_middle/src/mir/terminator.rs
index 4034a3a06e9..4249914346c 100644
--- a/compiler/rustc_middle/src/mir/terminator.rs
+++ b/compiler/rustc_middle/src/mir/terminator.rs
@@ -444,6 +444,14 @@ impl<'tcx> Terminator<'tcx> {
         self.kind.successors()
     }
 
+    /// Return `Some` if all successors are identical.
+    #[inline]
+    pub fn identical_successor(&self) -> Option<BasicBlock> {
+        let mut successors = self.successors();
+        let first_succ = successors.next()?;
+        if successors.all(|succ| first_succ == succ) { Some(first_succ) } else { None }
+    }
+
     #[inline]
     pub fn successors_mut<'a>(&'a mut self, f: impl FnMut(&'a mut BasicBlock)) {
         self.kind.successors_mut(f)
diff --git a/compiler/rustc_middle/src/mir/visit.rs b/compiler/rustc_middle/src/mir/visit.rs
index f3923477800..9654e189f2e 100644
--- a/compiler/rustc_middle/src/mir/visit.rs
+++ b/compiler/rustc_middle/src/mir/visit.rs
@@ -95,6 +95,14 @@ macro_rules! make_mir_visitor {
                 self.super_source_scope_data(scope_data);
             }
 
+            fn visit_statement_debuginfo(
+                &mut self,
+                stmt_debuginfo: & $($mutability)? StmtDebugInfo<'tcx>,
+                location: Location
+            ) {
+                self.super_statement_debuginfo(stmt_debuginfo, location);
+            }
+
             fn visit_statement(
                 &mut self,
                 statement: & $($mutability)? Statement<'tcx>,
@@ -301,6 +309,7 @@ macro_rules! make_mir_visitor {
             {
                 let BasicBlockData {
                     statements,
+                    after_last_stmt_debuginfos,
                     terminator,
                     is_cleanup: _
                 } = data;
@@ -312,8 +321,11 @@ macro_rules! make_mir_visitor {
                     index += 1;
                 }
 
+                let location = Location { block, statement_index: index };
+                for debuginfo in after_last_stmt_debuginfos as & $($mutability)? [_] {
+                    self.visit_statement_debuginfo(debuginfo, location);
+                }
                 if let Some(terminator) = terminator {
-                    let location = Location { block, statement_index: index };
                     self.visit_terminator(terminator, location);
                 }
             }
@@ -376,14 +388,45 @@ macro_rules! make_mir_visitor {
                 }
             }
 
+            fn super_statement_debuginfo(
+                &mut self,
+                stmt_debuginfo: & $($mutability)? StmtDebugInfo<'tcx>,
+                location: Location
+            ) {
+                match stmt_debuginfo {
+                    StmtDebugInfo::AssignRef(local, place) => {
+                        self.visit_local(
+                            $(& $mutability)? *local,
+                            PlaceContext::NonUse(NonUseContext::VarDebugInfo),
+                            location
+                        );
+                        self.visit_place(
+                            place,
+                            PlaceContext::NonUse(NonUseContext::VarDebugInfo),
+                            location
+                        );
+                    },
+                    StmtDebugInfo::InvalidAssign(local) => {
+                        self.visit_local(
+                            $(& $mutability)? *local,
+                            PlaceContext::NonUse(NonUseContext::VarDebugInfo),
+                            location
+                        );
+                    }
+                }
+            }
+
             fn super_statement(
                 &mut self,
                 statement: & $($mutability)? Statement<'tcx>,
                 location: Location
             ) {
-                let Statement { source_info, kind } = statement;
+                let Statement { source_info, kind, debuginfos } = statement;
 
                 self.visit_source_info(source_info);
+                for debuginfo in debuginfos as & $($mutability)? [_] {
+                    self.visit_statement_debuginfo(debuginfo, location);
+                }
                 match kind {
                     StatementKind::Assign(box (place, rvalue)) => {
                         self.visit_assign(place, rvalue, location);
diff --git a/compiler/rustc_mir_dataflow/src/impls/liveness.rs b/compiler/rustc_mir_dataflow/src/impls/liveness.rs
index 5eba474a60c..f6aaa65ad9f 100644
--- a/compiler/rustc_mir_dataflow/src/impls/liveness.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/liveness.rs
@@ -210,6 +210,7 @@ impl DefUse {
 /// All of the caveats of `MaybeLiveLocals` apply.
 pub struct MaybeTransitiveLiveLocals<'a> {
     always_live: &'a DenseBitSet<Local>,
+    debuginfo_locals: &'a DenseBitSet<Local>,
 }
 
 impl<'a> MaybeTransitiveLiveLocals<'a> {
@@ -217,8 +218,48 @@ impl<'a> MaybeTransitiveLiveLocals<'a> {
     /// considered live.
     ///
     /// This should include at least all locals that are ever borrowed.
-    pub fn new(always_live: &'a DenseBitSet<Local>) -> Self {
-        MaybeTransitiveLiveLocals { always_live }
+    pub fn new(
+        always_live: &'a DenseBitSet<Local>,
+        debuginfo_locals: &'a DenseBitSet<Local>,
+    ) -> Self {
+        MaybeTransitiveLiveLocals { always_live, debuginfo_locals }
+    }
+
+    pub fn can_be_removed_if_dead<'tcx>(
+        stmt_kind: &StatementKind<'tcx>,
+        always_live: &DenseBitSet<Local>,
+        debuginfo_locals: &'a DenseBitSet<Local>,
+    ) -> Option<Place<'tcx>> {
+        // Compute the place that we are storing to, if any
+        let destination = match stmt_kind {
+            StatementKind::Assign(box (place, rvalue)) => (rvalue.is_safe_to_remove()
+                // FIXME: We are not sure how we should represent this debugging information for some statements,
+                // keep it for now.
+                && (!debuginfo_locals.contains(place.local)
+                    || (place.as_local().is_some() && stmt_kind.as_debuginfo().is_some())))
+            .then_some(*place),
+            StatementKind::SetDiscriminant { place, .. } | StatementKind::Deinit(place) => {
+                (!debuginfo_locals.contains(place.local)).then_some(**place)
+            }
+            StatementKind::FakeRead(_)
+            | StatementKind::StorageLive(_)
+            | StatementKind::StorageDead(_)
+            | StatementKind::Retag(..)
+            | StatementKind::AscribeUserType(..)
+            | StatementKind::PlaceMention(..)
+            | StatementKind::Coverage(..)
+            | StatementKind::Intrinsic(..)
+            | StatementKind::ConstEvalCounter
+            | StatementKind::BackwardIncompatibleDropHint { .. }
+            | StatementKind::Nop => None,
+        };
+        if let Some(destination) = destination
+            && !destination.is_indirect()
+            && !always_live.contains(destination.local)
+        {
+            return Some(destination);
+        }
+        None
     }
 }
 
@@ -243,32 +284,12 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
         statement: &mir::Statement<'tcx>,
         location: Location,
     ) {
-        // Compute the place that we are storing to, if any
-        let destination = match &statement.kind {
-            StatementKind::Assign(assign) => assign.1.is_safe_to_remove().then_some(assign.0),
-            StatementKind::SetDiscriminant { place, .. } | StatementKind::Deinit(place) => {
-                Some(**place)
-            }
-            StatementKind::FakeRead(_)
-            | StatementKind::StorageLive(_)
-            | StatementKind::StorageDead(_)
-            | StatementKind::Retag(..)
-            | StatementKind::AscribeUserType(..)
-            | StatementKind::PlaceMention(..)
-            | StatementKind::Coverage(..)
-            | StatementKind::Intrinsic(..)
-            | StatementKind::ConstEvalCounter
-            | StatementKind::BackwardIncompatibleDropHint { .. }
-            | StatementKind::Nop => None,
-        };
-        if let Some(destination) = destination {
-            if !destination.is_indirect()
-                && !state.contains(destination.local)
-                && !self.always_live.contains(destination.local)
-            {
-                // This store is dead
-                return;
-            }
+        if let Some(destination) =
+            Self::can_be_removed_if_dead(&statement.kind, &self.always_live, &self.debuginfo_locals)
+            && !state.contains(destination.local)
+        {
+            // This store is dead
+            return;
         }
         TransferFunction(state).visit_statement(statement, location);
     }
diff --git a/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs b/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
index 4be67b873f7..b0bf7f484be 100644
--- a/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
+++ b/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
@@ -36,7 +36,9 @@ impl<'tcx> crate::MirPass<'tcx> for CleanupPostBorrowck {
                         CoverageKind::BlockMarker { .. } | CoverageKind::SpanMarker { .. },
                     )
                     | StatementKind::FakeRead(..)
-                    | StatementKind::BackwardIncompatibleDropHint { .. } => statement.make_nop(),
+                    | StatementKind::BackwardIncompatibleDropHint { .. } => {
+                        statement.make_nop(true)
+                    }
                     StatementKind::Assign(box (
                         _,
                         Rvalue::Cast(
diff --git a/compiler/rustc_mir_transform/src/copy_prop.rs b/compiler/rustc_mir_transform/src/copy_prop.rs
index cddeefca681..f0bc286a940 100644
--- a/compiler/rustc_mir_transform/src/copy_prop.rs
+++ b/compiler/rustc_mir_transform/src/copy_prop.rs
@@ -138,7 +138,7 @@ impl<'tcx> MutVisitor<'tcx> for Replacer<'_, 'tcx> {
         if let StatementKind::StorageLive(l) | StatementKind::StorageDead(l) = stmt.kind
             && self.storage_to_remove.contains(l)
         {
-            stmt.make_nop();
+            stmt.make_nop(true);
             return;
         }
 
@@ -150,7 +150,7 @@ impl<'tcx> MutVisitor<'tcx> for Replacer<'_, 'tcx> {
                 *rhs
             && lhs == rhs
         {
-            stmt.make_nop();
+            stmt.make_nop(true);
         }
     }
 }
diff --git a/compiler/rustc_mir_transform/src/coroutine.rs b/compiler/rustc_mir_transform/src/coroutine.rs
index c5cd06f170c..814eded910d 100644
--- a/compiler/rustc_mir_transform/src/coroutine.rs
+++ b/compiler/rustc_mir_transform/src/coroutine.rs
@@ -411,7 +411,7 @@ impl<'tcx> MutVisitor<'tcx> for TransformVisitor<'tcx> {
             if let StatementKind::StorageLive(l) | StatementKind::StorageDead(l) = s.kind
                 && self.remap.contains(l)
             {
-                s.make_nop();
+                s.make_nop(true);
             }
         }
 
diff --git a/compiler/rustc_mir_transform/src/dead_store_elimination.rs b/compiler/rustc_mir_transform/src/dead_store_elimination.rs
index eea2b0990d7..732c3dcd44a 100644
--- a/compiler/rustc_mir_transform/src/dead_store_elimination.rs
+++ b/compiler/rustc_mir_transform/src/dead_store_elimination.rs
@@ -22,21 +22,22 @@ use rustc_mir_dataflow::impls::{
     LivenessTransferFunction, MaybeTransitiveLiveLocals, borrowed_locals,
 };
 
+use crate::simplify::UsedInStmtLocals;
 use crate::util::is_within_packed;
 
 /// Performs the optimization on the body
 ///
 /// The `borrowed` set must be a `DenseBitSet` of all the locals that are ever borrowed in this
 /// body. It can be generated via the [`borrowed_locals`] function.
-fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+/// Returns true if any instruction is eliminated.
+fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) -> bool {
     let borrowed_locals = borrowed_locals(body);
 
     // If the user requests complete debuginfo, mark the locals that appear in it as live, so
     // we don't remove assignments to them.
-    let mut always_live = debuginfo_locals(body);
-    always_live.union(&borrowed_locals);
+    let debuginfo_locals = debuginfo_locals(body);
 
-    let mut live = MaybeTransitiveLiveLocals::new(&always_live)
+    let mut live = MaybeTransitiveLiveLocals::new(&borrowed_locals, &debuginfo_locals)
         .iterate_to_fixpoint(tcx, body, None)
         .into_results_cursor(body);
 
@@ -75,47 +76,36 @@ fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         }
 
         for (statement_index, statement) in bb_data.statements.iter().enumerate().rev() {
-            let loc = Location { block: bb, statement_index };
-            if let StatementKind::Assign(assign) = &statement.kind {
-                if !assign.1.is_safe_to_remove() {
-                    continue;
-                }
-            }
-            match &statement.kind {
-                StatementKind::Assign(box (place, _))
-                | StatementKind::SetDiscriminant { place: box place, .. }
-                | StatementKind::Deinit(box place) => {
-                    if !place.is_indirect() && !always_live.contains(place.local) {
-                        live.seek_before_primary_effect(loc);
-                        if !live.get().contains(place.local) {
-                            patch.push(loc);
-                        }
-                    }
-                }
-                StatementKind::Retag(_, _)
-                | StatementKind::StorageLive(_)
-                | StatementKind::StorageDead(_)
-                | StatementKind::Coverage(_)
-                | StatementKind::Intrinsic(_)
-                | StatementKind::ConstEvalCounter
-                | StatementKind::PlaceMention(_)
-                | StatementKind::BackwardIncompatibleDropHint { .. }
-                | StatementKind::Nop => {}
-
-                StatementKind::FakeRead(_) | StatementKind::AscribeUserType(_, _) => {
-                    bug!("{:?} not found in this MIR phase!", statement.kind)
+            if let Some(destination) = MaybeTransitiveLiveLocals::can_be_removed_if_dead(
+                &statement.kind,
+                &borrowed_locals,
+                &debuginfo_locals,
+            ) {
+                let loc = Location { block: bb, statement_index };
+                live.seek_before_primary_effect(loc);
+                if !live.get().contains(destination.local) {
+                    let drop_debuginfo = !debuginfo_locals.contains(destination.local);
+                    // When eliminating a dead statement, we need to address
+                    // the debug information for that statement.
+                    assert!(
+                        drop_debuginfo || statement.kind.as_debuginfo().is_some(),
+                        "don't know how to retain the debug information for {:?}",
+                        statement.kind
+                    );
+                    patch.push((loc, drop_debuginfo));
                 }
             }
         }
     }
 
     if patch.is_empty() && call_operands_to_move.is_empty() {
-        return;
+        return false;
     }
+    let eliminated = !patch.is_empty();
 
     let bbs = body.basic_blocks.as_mut_preserves_cfg();
-    for Location { block, statement_index } in patch {
-        bbs[block].statements[statement_index].make_nop();
+    for (Location { block, statement_index }, drop_debuginfo) in patch {
+        bbs[block].statements[statement_index].make_nop(drop_debuginfo);
     }
     for (block, argument_index) in call_operands_to_move {
         let TerminatorKind::Call { ref mut args, .. } = bbs[block].terminator_mut().kind else {
@@ -125,6 +115,8 @@ fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         let Operand::Copy(place) = *arg else { bug!() };
         *arg = Operand::Move(place);
     }
+
+    eliminated
 }
 
 pub(super) enum DeadStoreElimination {
@@ -145,7 +137,12 @@ impl<'tcx> crate::MirPass<'tcx> for DeadStoreElimination {
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        eliminate(tcx, body);
+        if eliminate(tcx, body) {
+            UsedInStmtLocals::new(body).remove_unused_storage_annotations(body);
+            for data in body.basic_blocks.as_mut_preserves_cfg() {
+                data.strip_nops();
+            }
+        }
     }
 
     fn is_required(&self) -> bool {
diff --git a/compiler/rustc_mir_transform/src/dest_prop.rs b/compiler/rustc_mir_transform/src/dest_prop.rs
index 74c22ff10c1..1f38433fa5a 100644
--- a/compiler/rustc_mir_transform/src/dest_prop.rs
+++ b/compiler/rustc_mir_transform/src/dest_prop.rs
@@ -276,7 +276,7 @@ impl<'tcx> MutVisitor<'tcx> for Merger<'tcx> {
             StatementKind::StorageDead(local) | StatementKind::StorageLive(local)
                 if self.merged_locals.contains(*local) =>
             {
-                statement.make_nop();
+                statement.make_nop(true);
                 return;
             }
             _ => (),
@@ -291,7 +291,7 @@ impl<'tcx> MutVisitor<'tcx> for Merger<'tcx> {
                         // (this includes the original statement we wanted to eliminate).
                         if dest == place {
                             debug!("{:?} turned into self-assignment, deleting", location);
-                            statement.make_nop();
+                            statement.make_nop(true);
                         }
                     }
                     _ => {}
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs
index 99691d9e045..3ff8dc6dbb3 100644
--- a/compiler/rustc_mir_transform/src/gvn.rs
+++ b/compiler/rustc_mir_transform/src/gvn.rs
@@ -1877,7 +1877,7 @@ impl<'tcx> MutVisitor<'tcx> for StorageRemover<'tcx> {
             StatementKind::StorageLive(l) | StatementKind::StorageDead(l)
                 if self.reused_locals.contains(l) =>
             {
-                stmt.make_nop()
+                stmt.make_nop(true)
             }
             _ => self.super_statement(stmt, loc),
         }
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index 3d49eb4e8ef..8593e25d6aa 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -21,7 +21,7 @@ use tracing::{debug, instrument, trace, trace_span};
 
 use crate::cost_checker::{CostChecker, is_call_like};
 use crate::deref_separator::deref_finder;
-use crate::simplify::simplify_cfg;
+use crate::simplify::{UsedInStmtLocals, simplify_cfg};
 use crate::validate::validate_types;
 use crate::{check_inline, util};
 
@@ -935,7 +935,7 @@ fn inline_call<'tcx, I: Inliner<'tcx>>(
         in_cleanup_block: false,
         return_block,
         tcx,
-        always_live_locals: DenseBitSet::new_filled(callee_body.local_decls.len()),
+        always_live_locals: UsedInStmtLocals::new(&callee_body).locals,
     };
 
     // Map all `Local`s, `SourceScope`s and `BasicBlock`s to new ones
@@ -995,6 +995,10 @@ fn inline_call<'tcx, I: Inliner<'tcx>>(
         // people working on rust can build with or without debuginfo while
         // still getting consistent results from the mir-opt tests.
         caller_body.var_debug_info.append(&mut callee_body.var_debug_info);
+    } else {
+        for bb in callee_body.basic_blocks_mut() {
+            bb.drop_debuginfo();
+        }
     }
     caller_body.basic_blocks_mut().append(callee_body.basic_blocks_mut());
 
diff --git a/compiler/rustc_mir_transform/src/large_enums.rs b/compiler/rustc_mir_transform/src/large_enums.rs
index 1a91d6bd7da..1b90e9158f6 100644
--- a/compiler/rustc_mir_transform/src/large_enums.rs
+++ b/compiler/rustc_mir_transform/src/large_enums.rs
@@ -156,7 +156,7 @@ impl<'tcx> crate::MirPass<'tcx> for EnumSizeOpt {
                     patch.add_statement(location, stmt);
                 }
 
-                st.make_nop();
+                st.make_nop(true);
             }
         }
 
diff --git a/compiler/rustc_mir_transform/src/patch.rs b/compiler/rustc_mir_transform/src/patch.rs
index cc8ea76011b..2c535d011a0 100644
--- a/compiler/rustc_mir_transform/src/patch.rs
+++ b/compiler/rustc_mir_transform/src/patch.rs
@@ -270,7 +270,7 @@ impl<'tcx> MirPatch<'tcx> {
         body.local_decls.extend(self.new_locals);
 
         for loc in self.nop_statements {
-            bbs[loc.block].statements[loc.statement_index].make_nop();
+            bbs[loc.block].statements[loc.statement_index].make_nop(true);
         }
 
         let mut new_statements = self.new_statements;
diff --git a/compiler/rustc_mir_transform/src/promote_consts.rs b/compiler/rustc_mir_transform/src/promote_consts.rs
index 48ddf5a1bca..c7dc18a4a13 100644
--- a/compiler/rustc_mir_transform/src/promote_consts.rs
+++ b/compiler/rustc_mir_transform/src/promote_consts.rs
@@ -1049,7 +1049,7 @@ fn promote_candidates<'tcx>(
     // Eliminate assignments to, and drops of promoted temps.
     let promoted = |index: Local| temps[index] == TempState::PromotedOut;
     for block in body.basic_blocks_mut() {
-        block.statements.retain(|statement| match &statement.kind {
+        block.retain_statements(|statement| match &statement.kind {
             StatementKind::Assign(box (place, _)) => {
                 if let Some(index) = place.as_local() {
                     !promoted(index)
diff --git a/compiler/rustc_mir_transform/src/ref_prop.rs b/compiler/rustc_mir_transform/src/ref_prop.rs
index b9d6e74ecae..deb0a146476 100644
--- a/compiler/rustc_mir_transform/src/ref_prop.rs
+++ b/compiler/rustc_mir_transform/src/ref_prop.rs
@@ -435,7 +435,7 @@ impl<'tcx> MutVisitor<'tcx> for Replacer<'tcx> {
             StatementKind::StorageLive(l) | StatementKind::StorageDead(l)
                 if self.storage_to_remove.contains(l) =>
             {
-                stmt.make_nop();
+                stmt.make_nop(true);
             }
             // Do not remove assignments as they may still be useful for debuginfo.
             _ => self.super_statement(stmt, loc),
diff --git a/compiler/rustc_mir_transform/src/remove_place_mention.rs b/compiler/rustc_mir_transform/src/remove_place_mention.rs
index cb598ceb4df..d56b51bb496 100644
--- a/compiler/rustc_mir_transform/src/remove_place_mention.rs
+++ b/compiler/rustc_mir_transform/src/remove_place_mention.rs
@@ -14,7 +14,7 @@ impl<'tcx> crate::MirPass<'tcx> for RemovePlaceMention {
     fn run_pass(&self, _: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         trace!("Running RemovePlaceMention on {:?}", body.source);
         for data in body.basic_blocks.as_mut_preserves_cfg() {
-            data.statements.retain(|statement| match statement.kind {
+            data.retain_statements(|statement| match statement.kind {
                 StatementKind::PlaceMention(..) | StatementKind::Nop => false,
                 _ => true,
             })
diff --git a/compiler/rustc_mir_transform/src/remove_storage_markers.rs b/compiler/rustc_mir_transform/src/remove_storage_markers.rs
index 1ae33c00968..cb97d2c865a 100644
--- a/compiler/rustc_mir_transform/src/remove_storage_markers.rs
+++ b/compiler/rustc_mir_transform/src/remove_storage_markers.rs
@@ -14,7 +14,7 @@ impl<'tcx> crate::MirPass<'tcx> for RemoveStorageMarkers {
     fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         trace!("Running RemoveStorageMarkers on {:?}", body.source);
         for data in body.basic_blocks.as_mut_preserves_cfg() {
-            data.statements.retain(|statement| match statement.kind {
+            data.retain_statements(|statement| match statement.kind {
                 StatementKind::StorageLive(..)
                 | StatementKind::StorageDead(..)
                 | StatementKind::Nop => false,
diff --git a/compiler/rustc_mir_transform/src/remove_zsts.rs b/compiler/rustc_mir_transform/src/remove_zsts.rs
index c4dc8638b26..90c1b3520b9 100644
--- a/compiler/rustc_mir_transform/src/remove_zsts.rs
+++ b/compiler/rustc_mir_transform/src/remove_zsts.rs
@@ -141,7 +141,7 @@ impl<'tcx> MutVisitor<'tcx> for Replacer<'_, 'tcx> {
             && let ty = place_for_ty.ty(self.local_decls, self.tcx).ty
             && self.known_to_be_zst(ty)
         {
-            statement.make_nop();
+            statement.make_nop(true);
         } else {
             self.super_statement(statement, loc);
         }
diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs
index 75917d23883..8b5efb74205 100644
--- a/compiler/rustc_mir_transform/src/simplify.rs
+++ b/compiler/rustc_mir_transform/src/simplify.rs
@@ -35,10 +35,12 @@
 //! pre-"runtime" MIR!
 
 use itertools::Itertools as _;
+use rustc_index::bit_set::DenseBitSet;
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
+use rustc_mir_dataflow::debuginfo::debuginfo_locals;
 use rustc_span::DUMMY_SP;
 use smallvec::SmallVec;
 use tracing::{debug, trace};
@@ -142,7 +144,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
         // statements itself to avoid moving the (relatively) large statements twice.
         // We do not push the statements directly into the target block (`bb`) as that is slower
         // due to additional reallocations
-        let mut merged_blocks = Vec::new();
+        let mut merged_blocks: Vec<BasicBlock> = Vec::new();
         let mut outer_changed = false;
         loop {
             let mut changed = false;
@@ -157,8 +159,9 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
                 let mut terminator =
                     self.basic_blocks[bb].terminator.take().expect("invalid terminator state");
 
-                terminator
-                    .successors_mut(|successor| self.collapse_goto_chain(successor, &mut changed));
+                terminator.successors_mut(|successor| {
+                    self.collapse_goto_chain(successor, &mut changed);
+                });
 
                 let mut inner_changed = true;
                 merged_blocks.clear();
@@ -175,10 +178,18 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
                 if statements_to_merge > 0 {
                     let mut statements = std::mem::take(&mut self.basic_blocks[bb].statements);
                     statements.reserve(statements_to_merge);
+                    let mut parent_bb_last_debuginfos =
+                        std::mem::take(&mut self.basic_blocks[bb].after_last_stmt_debuginfos);
                     for &from in &merged_blocks {
+                        if let Some(stmt) = self.basic_blocks[from].statements.first_mut() {
+                            stmt.debuginfos.prepend(&mut parent_bb_last_debuginfos);
+                        }
                         statements.append(&mut self.basic_blocks[from].statements);
+                        parent_bb_last_debuginfos =
+                            std::mem::take(&mut self.basic_blocks[from].after_last_stmt_debuginfos);
                     }
                     self.basic_blocks[bb].statements = statements;
+                    self.basic_blocks[bb].after_last_stmt_debuginfos = parent_bb_last_debuginfos;
                 }
 
                 self.basic_blocks[bb].terminator = Some(terminator);
@@ -218,10 +229,14 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
         // goto chains. We should probably benchmark different sizes.
         let mut terminators: SmallVec<[_; 1]> = Default::default();
         let mut current = *start;
+        // If each successor has only one predecessor, it's a trivial goto chain.
+        // We can move all debuginfos to the last basic block.
+        let mut trivial_goto_chain = true;
         while let Some(terminator) = self.take_terminator_if_simple_goto(current) {
             let Terminator { kind: TerminatorKind::Goto { target }, .. } = terminator else {
                 unreachable!();
             };
+            trivial_goto_chain &= self.pred_count[target] == 1;
             terminators.push((current, terminator));
             current = target;
         }
@@ -233,6 +248,17 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
             else {
                 unreachable!();
             };
+            if trivial_goto_chain {
+                let mut pred_debuginfos =
+                    std::mem::take(&mut self.basic_blocks[current].after_last_stmt_debuginfos);
+                let debuginfos = if let Some(stmt) = self.basic_blocks[last].statements.first_mut()
+                {
+                    &mut stmt.debuginfos
+                } else {
+                    &mut self.basic_blocks[last].after_last_stmt_debuginfos
+                };
+                debuginfos.prepend(&mut pred_debuginfos);
+            }
             *changed |= *target != last;
             *target = last;
             debug!("collapsing goto chain from {:?} to {:?}", current, target);
@@ -303,7 +329,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
 
     fn strip_nops(&mut self) {
         for blk in self.basic_blocks.iter_mut() {
-            blk.statements.retain(|stmt| !matches!(stmt.kind, StatementKind::Nop))
+            blk.strip_nops();
         }
     }
 }
@@ -476,17 +502,22 @@ fn make_local_map<V>(
 /// Keeps track of used & unused locals.
 struct UsedLocals {
     increment: bool,
-    arg_count: u32,
     use_count: IndexVec<Local, u32>,
+    always_used: DenseBitSet<Local>,
 }
 
 impl UsedLocals {
     /// Determines which locals are used & unused in the given body.
     fn new(body: &Body<'_>) -> Self {
+        let mut always_used = debuginfo_locals(body);
+        always_used.insert(RETURN_PLACE);
+        for arg in body.args_iter() {
+            always_used.insert(arg);
+        }
         let mut this = Self {
             increment: true,
-            arg_count: body.arg_count.try_into().unwrap(),
             use_count: IndexVec::from_elem(0, &body.local_decls),
+            always_used,
         };
         this.visit_body(body);
         this
@@ -494,10 +525,16 @@ impl UsedLocals {
 
     /// Checks if local is used.
     ///
-    /// Return place and arguments are always considered used.
+    /// Return place, arguments, var debuginfo are always considered used.
     fn is_used(&self, local: Local) -> bool {
-        trace!("is_used({:?}): use_count: {:?}", local, self.use_count[local]);
-        local.as_u32() <= self.arg_count || self.use_count[local] != 0
+        trace!(
+            "is_used({:?}): use_count: {:?}, always_used: {}",
+            local,
+            self.use_count[local],
+            self.always_used.contains(local)
+        );
+        // To keep things simple, we don't handle debugging information here, these are in DSE.
+        self.always_used.contains(local) || self.use_count[local] != 0
     }
 
     /// Updates the use counts to reflect the removal of given statement.
@@ -539,10 +576,10 @@ impl<'tcx> Visitor<'tcx> for UsedLocals {
                 self.super_statement(statement, location);
             }
 
-            StatementKind::ConstEvalCounter | StatementKind::Nop => {}
-
-            StatementKind::StorageLive(_local) | StatementKind::StorageDead(_local) => {}
-
+            StatementKind::ConstEvalCounter
+            | StatementKind::Nop
+            | StatementKind::StorageLive(..)
+            | StatementKind::StorageDead(..) => {}
             StatementKind::Assign(box (ref place, ref rvalue)) => {
                 if rvalue.is_safe_to_remove() {
                     self.visit_lhs(place, location);
@@ -560,7 +597,10 @@ impl<'tcx> Visitor<'tcx> for UsedLocals {
         }
     }
 
-    fn visit_local(&mut self, local: Local, _ctx: PlaceContext, _location: Location) {
+    fn visit_local(&mut self, local: Local, ctx: PlaceContext, _location: Location) {
+        if matches!(ctx, PlaceContext::NonUse(_)) {
+            return;
+        }
         if self.increment {
             self.use_count[local] += 1;
         } else {
@@ -583,28 +623,26 @@ fn remove_unused_definitions_helper(used_locals: &mut UsedLocals, body: &mut Bod
 
         for data in body.basic_blocks.as_mut_preserves_cfg() {
             // Remove unnecessary StorageLive and StorageDead annotations.
-            data.statements.retain(|statement| {
-                let keep = match &statement.kind {
+            for statement in data.statements.iter_mut() {
+                let keep_statement = match &statement.kind {
                     StatementKind::StorageLive(local) | StatementKind::StorageDead(local) => {
                         used_locals.is_used(*local)
                     }
-                    StatementKind::Assign(box (place, _)) => used_locals.is_used(place.local),
-
-                    StatementKind::SetDiscriminant { place, .. }
-                    | StatementKind::BackwardIncompatibleDropHint { place, reason: _ }
-                    | StatementKind::Deinit(place) => used_locals.is_used(place.local),
-                    StatementKind::Nop => false,
-                    _ => true,
+                    StatementKind::Assign(box (place, _))
+                    | StatementKind::SetDiscriminant { box place, .. }
+                    | StatementKind::BackwardIncompatibleDropHint { box place, .. }
+                    | StatementKind::Deinit(box place) => used_locals.is_used(place.local),
+                    _ => continue,
                 };
-
-                if !keep {
-                    trace!("removing statement {:?}", statement);
-                    modified = true;
-                    used_locals.statement_removed(statement);
+                if keep_statement {
+                    continue;
                 }
-
-                keep
-            });
+                trace!("removing statement {:?}", statement);
+                modified = true;
+                used_locals.statement_removed(statement);
+                statement.make_nop(true);
+            }
+            data.strip_nops();
         }
     }
 }
@@ -619,7 +657,62 @@ impl<'tcx> MutVisitor<'tcx> for LocalUpdater<'tcx> {
         self.tcx
     }
 
+    fn visit_statement_debuginfo(
+        &mut self,
+        stmt_debuginfo: &mut StmtDebugInfo<'tcx>,
+        location: Location,
+    ) {
+        match stmt_debuginfo {
+            StmtDebugInfo::AssignRef(local, place) => {
+                if place.as_ref().accessed_locals().any(|local| self.map[local].is_none()) {
+                    *stmt_debuginfo = StmtDebugInfo::InvalidAssign(*local);
+                }
+            }
+            StmtDebugInfo::InvalidAssign(_) => {}
+        }
+        self.super_statement_debuginfo(stmt_debuginfo, location);
+    }
+
     fn visit_local(&mut self, l: &mut Local, _: PlaceContext, _: Location) {
         *l = self.map[*l].unwrap();
     }
 }
+
+pub(crate) struct UsedInStmtLocals {
+    pub(crate) locals: DenseBitSet<Local>,
+}
+
+impl UsedInStmtLocals {
+    pub(crate) fn new(body: &Body<'_>) -> Self {
+        let mut this = Self { locals: DenseBitSet::new_empty(body.local_decls.len()) };
+        this.visit_body(body);
+        this
+    }
+
+    pub(crate) fn remove_unused_storage_annotations<'tcx>(&self, body: &mut Body<'tcx>) {
+        for data in body.basic_blocks.as_mut_preserves_cfg() {
+            // Remove unnecessary StorageLive and StorageDead annotations.
+            for statement in data.statements.iter_mut() {
+                let keep_statement = match &statement.kind {
+                    StatementKind::StorageLive(local) | StatementKind::StorageDead(local) => {
+                        self.locals.contains(*local)
+                    }
+                    _ => continue,
+                };
+                if keep_statement {
+                    continue;
+                }
+                statement.make_nop(true);
+            }
+        }
+    }
+}
+
+impl<'tcx> Visitor<'tcx> for UsedInStmtLocals {
+    fn visit_local(&mut self, local: Local, context: PlaceContext, _: Location) {
+        if matches!(context, PlaceContext::NonUse(_)) {
+            return;
+        }
+        self.locals.insert(local);
+    }
+}
diff --git a/compiler/rustc_mir_transform/src/simplify_comparison_integral.rs b/compiler/rustc_mir_transform/src/simplify_comparison_integral.rs
index c60eb566521..4597439e269 100644
--- a/compiler/rustc_mir_transform/src/simplify_comparison_integral.rs
+++ b/compiler/rustc_mir_transform/src/simplify_comparison_integral.rs
@@ -76,7 +76,7 @@ impl<'tcx> crate::MirPass<'tcx> for SimplifyComparisonIntegral {
             // delete comparison statement if it the value being switched on was moved, which means
             // it can not be user later on
             if opt.can_remove_bin_op_stmt {
-                bb.statements[opt.bin_op_stmt_idx].make_nop();
+                bb.statements[opt.bin_op_stmt_idx].make_nop(true);
             } else {
                 // if the integer being compared to a const integral is being moved into the
                 // comparison, e.g `_2 = Eq(move _3, const 'x');`
@@ -136,7 +136,7 @@ impl<'tcx> crate::MirPass<'tcx> for SimplifyComparisonIntegral {
         }
 
         for (idx, bb_idx) in storage_deads_to_remove {
-            body.basic_blocks_mut()[bb_idx].statements[idx].make_nop();
+            body.basic_blocks_mut()[bb_idx].statements[idx].make_nop(true);
         }
 
         for (idx, stmt) in storage_deads_to_insert {
diff --git a/compiler/rustc_mir_transform/src/sroa.rs b/compiler/rustc_mir_transform/src/sroa.rs
index 38769885f36..99f10b8d91d 100644
--- a/compiler/rustc_mir_transform/src/sroa.rs
+++ b/compiler/rustc_mir_transform/src/sroa.rs
@@ -318,7 +318,7 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
                     for (_, _, fl) in final_locals {
                         self.patch.add_statement(location, StatementKind::StorageLive(fl));
                     }
-                    statement.make_nop();
+                    statement.make_nop(true);
                 }
                 return;
             }
@@ -327,7 +327,7 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
                     for (_, _, fl) in final_locals {
                         self.patch.add_statement(location, StatementKind::StorageDead(fl));
                     }
-                    statement.make_nop();
+                    statement.make_nop(true);
                 }
                 return;
             }
@@ -337,7 +337,7 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
                         self.patch
                             .add_statement(location, StatementKind::Deinit(Box::new(fl.into())));
                     }
-                    statement.make_nop();
+                    statement.make_nop(true);
                     return;
                 }
             }
@@ -367,7 +367,7 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
                             );
                         }
                     }
-                    statement.make_nop();
+                    statement.make_nop(true);
                     return;
                 }
             }
@@ -429,7 +429,7 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
                             StatementKind::Assign(Box::new((new_local.into(), rvalue))),
                         );
                     }
-                    statement.make_nop();
+                    statement.make_nop(true);
                     return;
                 }
             }
diff --git a/compiler/rustc_mir_transform/src/strip_debuginfo.rs b/compiler/rustc_mir_transform/src/strip_debuginfo.rs
index 9ede8aa79c4..7fec25ccb52 100644
--- a/compiler/rustc_mir_transform/src/strip_debuginfo.rs
+++ b/compiler/rustc_mir_transform/src/strip_debuginfo.rs
@@ -1,5 +1,6 @@
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
+use rustc_mir_dataflow::debuginfo::debuginfo_locals;
 use rustc_session::config::MirStripDebugInfo;
 
 /// Conditionally remove some of the VarDebugInfo in MIR.
@@ -30,6 +31,22 @@ impl<'tcx> crate::MirPass<'tcx> for StripDebugInfo {
                     if place.local.as_usize() <= body.arg_count && place.local != RETURN_PLACE,
             )
         });
+
+        let debuginfo_locals = debuginfo_locals(body);
+        for data in body.basic_blocks.as_mut_preserves_cfg() {
+            for stmt in data.statements.iter_mut() {
+                stmt.debuginfos.retain(|debuginfo| match debuginfo {
+                    StmtDebugInfo::AssignRef(local, _) | StmtDebugInfo::InvalidAssign(local) => {
+                        debuginfo_locals.contains(*local)
+                    }
+                });
+            }
+            data.after_last_stmt_debuginfos.retain(|debuginfo| match debuginfo {
+                StmtDebugInfo::AssignRef(local, _) | StmtDebugInfo::InvalidAssign(local) => {
+                    debuginfo_locals.contains(*local)
+                }
+            });
+        }
     }
 
     fn is_required(&self) -> bool {
diff --git a/tests/codegen-llvm/debug-fndef-size.rs b/tests/codegen-llvm/debug-fndef-size.rs
index 8f716c34e7b..02629bd748c 100644
--- a/tests/codegen-llvm/debug-fndef-size.rs
+++ b/tests/codegen-llvm/debug-fndef-size.rs
@@ -16,5 +16,5 @@ pub fn main() {
 
 // CHECK: %compare.dbg.spill = alloca [0 x i8], align 1
 // CHECK: dbg{{.}}declare({{(metadata )?}}ptr %compare.dbg.spill, {{(metadata )?}}![[VAR:.*]], {{(metadata )?}}!DIExpression()
-// CHECK: ![[TYPE:.*]] = !DIDerivedType(tag: DW_TAG_pointer_type, name: "fn(&i32, &i32) -> core::cmp::Ordering", baseType: !{{.*}}, align: 8, dwarfAddressSpace: {{.*}})
-// CHECK: ![[VAR]] = !DILocalVariable(name: "compare", scope: !{{.*}}, file: !{{.*}}, line: {{.*}}, type: ![[TYPE]], align: 8)
+// CHECK-DAG: ![[TYPE:.*]] = !DIDerivedType(tag: DW_TAG_pointer_type, name: "fn(&i32, &i32) -> core::cmp::Ordering", baseType: !{{.*}}, align: 8, dwarfAddressSpace: {{.*}})
+// CHECK-DAG: ![[VAR]] = !DILocalVariable(name: "compare", scope: !{{.*}}, file: !{{.*}}, line: {{.*}}, type: ![[TYPE]], align: 8)
diff --git a/tests/codegen-llvm/debuginfo-dse.rs b/tests/codegen-llvm/debuginfo-dse.rs
new file mode 100644
index 00000000000..fd0c9f1c676
--- /dev/null
+++ b/tests/codegen-llvm/debuginfo-dse.rs
@@ -0,0 +1,362 @@
+//@ compile-flags: -Copt-level=3 -g -Zverify-llvm-ir -Zmerge-functions=disabled
+//@ revisions: CODEGEN OPTIMIZED
+//@[CODEGEN] compile-flags: -Cno-prepopulate-passes
+//@ only-64bit
+// ignore-tidy-linelength
+
+#![crate_type = "lib"]
+#![feature(repr_simd, rustc_attrs)]
+
+// The pass mode is direct and the backend represent is scalar.
+type Scalar = i32; // scalar(i32)
+type Scalar_Ref = &'static i32; // scalar(ptr)
+
+// The pass modes are pair and the backend represents are scalar pair.
+type Tuple_Scalar_Scalar = (i32, i32);
+struct Tuple_Ref_Scalar(&'static i32, i32);
+struct Tuple_ArrayRef_Scalar(&'static [i32; 16], i32); // pair(ptr, i32)
+impl Default for Tuple_ArrayRef_Scalar {
+    fn default() -> Tuple_ArrayRef_Scalar {
+        Tuple_ArrayRef_Scalar(&[0; 16], 0)
+    }
+}
+struct Tuple_Scalar_ArrayRef(i32, &'static [i32; 16]); // pair(i32, ptr)
+impl Default for Tuple_Scalar_ArrayRef {
+    fn default() -> Tuple_Scalar_ArrayRef {
+        Tuple_Scalar_ArrayRef(0, &[0; 16])
+    }
+}
+// The pass mode is indirect and the backend represent is memory.
+type Tuple_SliceRef_Scalar = (&'static [i32], i32);
+
+// The pass mode is pair and the backend represent is scalar pair.
+type SliceRef = &'static [i32]; // pair(ptr, i32)
+// The pass mode is indirect and the backend represent is memory.
+type Array = [i32; 16];
+// The pass mode is direct and the backend represent is scalar.
+type ArrayRef = &'static [i32; 16];
+
+// The pass mode is indirect and the backend represent is memory.
+type Typle_i32_i64_i8 = (i32, i64, i8);
+// The pass mode is indirect and the backend represent is memory.
+#[repr(C)]
+struct Aggregate_i32_Array_i8(i32, &'static [i32; 16], i8);
+
+type ZST = ();
+
+impl Default for Aggregate_i32_Array_i8 {
+    fn default() -> Aggregate_i32_Array_i8 {
+        Aggregate_i32_Array_i8(0, &[0; 16], 0)
+    }
+}
+// The pass mode is cast and the backend represent is scalar.
+#[derive(Default)]
+struct Aggregate_4xi8(i8, i8, i8, i8); // scalar(i32)
+
+// The pass mode is indirect and the backend represent is simd vector.
+#[repr(simd)]
+struct Simd_i32x4([i32; 4]);
+
+unsafe extern "Rust" {
+    #[rustc_nounwind]
+    safe fn opaque_fn();
+    #[rustc_nounwind]
+    safe fn opaque_ptr(_: *const core::ffi::c_void);
+}
+
+#[inline(never)]
+#[rustc_nounwind]
+fn opaque_use<T>(p: &T) {
+    opaque_ptr(&raw const p as *const _);
+}
+
+#[inline(never)]
+#[rustc_nounwind]
+fn opaque_read<T: Default>() -> T {
+    core::hint::black_box(T::default())
+}
+
+#[unsafe(no_mangle)]
+fn local_var() {
+    // CHECK-LABEL: define{{( dso_local)?}} void @local_var
+    let local_var_scalar: Scalar = opaque_read();
+    opaque_use(&local_var_scalar);
+    let dead_local_var_scalar: Scalar = opaque_read();
+    let local_var_aggregate_4xi8: Aggregate_4xi8 = opaque_read();
+    opaque_use(&local_var_aggregate_4xi8);
+    let local_var_aggregate_i32_array_i8: Aggregate_i32_Array_i8 = opaque_read();
+    opaque_use(&local_var_aggregate_i32_array_i8);
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+    // CHECK-NEXT: #dbg_value(ptr %local_var_scalar, [[ref_local_var_scalar:![0-9]+]], !DIExpression()
+    let ref_local_var_scalar = &local_var_scalar;
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_dead_local_var_scalar:![0-9]+]], !DIExpression()
+    let ref_dead_local_var_scalar = &dead_local_var_scalar;
+    // CHECK-NEXT: #dbg_value(ptr %local_var_aggregate_4xi8, [[ref_local_var_aggregate_4xi8:![0-9]+]], !DIExpression()
+    let ref_local_var_aggregate_4xi8 = &local_var_aggregate_4xi8;
+    // CHECK-NEXT: #dbg_value(ptr %local_var_aggregate_4xi8, [[ref_0_local_var_aggregate_4xi8:![0-9]+]], !DIExpression()
+    let ref_0_local_var_aggregate_4xi8 = &local_var_aggregate_4xi8.0;
+    // CHECK-NEXT: #dbg_value(ptr %local_var_aggregate_4xi8, [[ref_2_local_var_aggregate_4xi8:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 2, DW_OP_stack_value)
+    let ref_2_local_var_aggregate_4xi8 = &local_var_aggregate_4xi8.2;
+    // This introduces an extra load instruction.
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_1_1_local_var_aggregate_i32_array_i8:![0-9]+]], !DIExpression()
+    let ref_1_1_local_var_aggregate_i32_array_i8 = &local_var_aggregate_i32_array_i8.1[1];
+    // CHECK-NEXT: #dbg_value(ptr %local_var_aggregate_i32_array_i8, [[ref_2_local_var_aggregate_i32_array_i8:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 16, DW_OP_stack_value)
+    let ref_2_local_var_aggregate_i32_array_i8 = &local_var_aggregate_i32_array_i8.2;
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+}
+
+#[unsafe(no_mangle)]
+fn zst(zst: ZST, zst_ref: &ZST) {
+    // CHECK-LABEL: define{{( dso_local)?}} void @zst
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_zst:![0-9]+]], !DIExpression()
+    let ref_zst = &zst;
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_zst_ref:![0-9]+]], !DIExpression()
+    let ref_zst_ref = &zst_ref;
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+}
+
+// It only makes sense if the argument is a reference and it refer to projections.
+#[unsafe(no_mangle)]
+fn direct(
+    scalar: Scalar,
+    scalar_ref: Scalar_Ref,
+    array_ref: ArrayRef,
+    aggregate_4xi8_ref: &Aggregate_4xi8,
+) {
+    // CHECK-LABEL: define{{( dso_local)?}} void @direct
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_scalar:![0-9]+]], !DIExpression()
+    let ref_scalar = &scalar;
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_scalar_ref:![0-9]+]], !DIExpression()
+    let ref_scalar_ref = &scalar_ref;
+    // CHECK-NEXT: #dbg_value(ptr %array_ref, [[ref_0_array_ref:![0-9]+]], !DIExpression()
+    let ref_0_array_ref = &array_ref[0];
+    // CHECK-NEXT: #dbg_value(ptr %array_ref, [[ref_1_array_ref:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 4, DW_OP_stack_value)
+    let ref_1_array_ref = &array_ref[1];
+    // CHECK-NEXT: #dbg_value(ptr %aggregate_4xi8_ref, [[ref_1_aggregate_4xi8_ref:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 1, DW_OP_stack_value)
+    let ref_1_aggregate_4xi8_ref = &aggregate_4xi8_ref.1;
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+}
+
+// Arguments are passed through registers, the final values are poison.
+#[unsafe(no_mangle)]
+fn cast(aggregate_4xi8: Aggregate_4xi8) {
+    // CHECK-LABEL: define{{( dso_local)?}} void @cast(i32 %0)
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+    // The temporary allocated variable is eliminated.
+    // CODEGEN-NEXT: #dbg_value(ptr %aggregate_4xi8, [[ref_aggregate_4xi8:![0-9]+]], !DIExpression()
+    // OPTIMIZED-NEXT: #dbg_value(ptr undef, [[ref_aggregate_4xi8:![0-9]+]], !DIExpression()
+    let ref_aggregate_4xi8 = &aggregate_4xi8;
+    // CODEGEN-NEXT: #dbg_value(ptr %aggregate_4xi8, [[ref_0_aggregate_4xi8:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 1, DW_OP_stack_value)
+    // OPTIMIZED-NEXT: #dbg_value(ptr undef, [[ref_0_aggregate_4xi8:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 1, DW_OP_stack_value)
+    let ref_0_aggregate_4xi8 = &aggregate_4xi8.1;
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+}
+
+// Arguments are passed indirectly via a pointer.
+// The reference of argument is the pointer itself.
+#[unsafe(no_mangle)]
+fn indirect(
+    tuple_sliceref_scalar: Tuple_SliceRef_Scalar,
+    array: Array,
+    typle_i32_i64_i8: Typle_i32_i64_i8,
+    simd_i32x4: Simd_i32x4,
+) {
+    // CHECK-LABEL: define{{( dso_local)?}} void @indirect
+    // CHECK-SAME: (ptr{{.*}} %tuple_sliceref_scalar, ptr{{.*}} %array, ptr{{.*}} %typle_i32_i64_i8, ptr{{.*}} %simd_i32x4)
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+    // CHECK-NEXT: #dbg_value(ptr %tuple_sliceref_scalar, [[ref_tuple_sliceref_scalar:![0-9]+]], !DIExpression()
+    let ref_tuple_sliceref_scalar = &tuple_sliceref_scalar;
+    // CHECK-NEXT: #dbg_value(ptr %tuple_sliceref_scalar, [[ref_1_tuple_sliceref_scalar:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 16, DW_OP_stack_value)
+    let ref_1_tuple_sliceref_scalar = &tuple_sliceref_scalar.1;
+    // CHECK-NEXT: #dbg_value(ptr %array, [[ref_1_array:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 4, DW_OP_stack_value)
+    let ref_1_array = &array[1];
+    // CHECK-NEXT: #dbg_value(ptr %typle_i32_i64_i8, [[ref_1_typle_i32_i64_i8:![0-9]+]], !DIExpression()
+    let ref_1_typle_i32_i64_i8 = &typle_i32_i64_i8.1;
+    // CHECK-NEXT: #dbg_value(ptr %simd_i32x4, [[ref_simd_i32x4:![0-9]+]], !DIExpression()
+    let ref_simd_i32x4 = &simd_i32x4;
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+}
+
+// They are different MIR statements, but they have the same LLVM IR statement due to the ABI of arguments.
+// Both `direct_ref` and `indirect_byval` are passed as a pointer here.
+#[unsafe(no_mangle)]
+fn direct_ref_and_indirect(
+    direct_ref: &Aggregate_i32_Array_i8,
+    indirect_byval: Aggregate_i32_Array_i8,
+) {
+    // CHECK-LABEL: define{{( dso_local)?}} void @direct_ref_and_indirect
+    // CHECK-SAME: (ptr{{.*}} %direct_ref, ptr{{.*}} %indirect_byval)
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_direct_ref:![0-9]+]], !DIExpression()
+    let ref_direct_ref: &&Aggregate_i32_Array_i8 = &direct_ref;
+    // CHECK-NEXT: #dbg_value(ptr %direct_ref, [[ref_1_direct_ref:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 8, DW_OP_stack_value)
+    let ref_1_direct_ref = &direct_ref.1;
+    // CHECK-NEXT: #dbg_value(ptr %indirect_byval, [[ref_indirect_byval:![0-9]+]], !DIExpression()
+    let ref_indirect_byval: &Aggregate_i32_Array_i8 = &indirect_byval;
+    // CHECK-NEXT: #dbg_value(ptr %indirect_byval, [[ref_1_indirect_byval:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 8, DW_OP_stack_value)
+    let ref_1_indirect_byval = &indirect_byval.1;
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+}
+
+#[unsafe(no_mangle)]
+fn pair(
+    tuple_scalar_scalar: Tuple_Scalar_Scalar,
+    tuple_ref_scalar: Tuple_Ref_Scalar,
+    tuple_arrayref_scalar: Tuple_ArrayRef_Scalar,
+    tuple_scalar_arrayref: Tuple_Scalar_ArrayRef,
+    sliceref: SliceRef,
+) {
+    // CHECK-LABEL: define{{( dso_local)?}} void @pair
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_0_tuple_scalar_scalar:![0-9]+]], !DIExpression()
+    let ref_0_tuple_scalar_scalar = &tuple_scalar_scalar.0;
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_0_tuple_ref_scalar:![0-9]+]], !DIExpression()
+    let ref_0_tuple_ref_scalar = &tuple_ref_scalar.0;
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_1_tuple_ref_scalar:![0-9]+]], !DIExpression()
+    let ref_1_tuple_ref_scalar = &tuple_ref_scalar.1;
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_0_tuple_arrayref_scalar:![0-9]+]], !DIExpression()
+    let ref_0_tuple_arrayref_scalar = &tuple_arrayref_scalar.0;
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_1_tuple_arrayref_scalar:![0-9]+]], !DIExpression()
+    let ref_1_tuple_arrayref_scalar = &tuple_arrayref_scalar.1;
+    // FIXME: This can be a valid value.
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_0_1_tuple_arrayref_scalar:![0-9]+]], !DIExpression()
+    let ref_0_1_tuple_arrayref_scalar = &tuple_arrayref_scalar.0[1];
+    // FIXME: This can be a valid value.
+    // CHECK-NEXT: #dbg_value(ptr poison, [[ref_1_1_tuple_scalar_arrayref:![0-9]+]], !DIExpression()
+    let ref_1_1_tuple_scalar_arrayref = &tuple_scalar_arrayref.1[1];
+    // CHECK: #dbg_value(ptr %sliceref.0, [[ref_1_sliceref:![0-9]+]], !DIExpression(DW_OP_plus_uconst, 4, DW_OP_stack_value)
+    let ref_1_sliceref = &sliceref[1];
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct Foo(i32, i64, i32);
+
+#[repr(C)]
+pub struct Bar<'a> {
+    a: i32,
+    b: i64,
+    foo: &'a Foo,
+}
+
+#[unsafe(no_mangle)]
+pub fn dead_first(dead_first_foo: &Foo) -> &i32 {
+    // CHECK-LABEL: def {{.*}} ptr @dead_first
+    // CHECK-SAME: (ptr {{.*}} [[ARG_dead_first_foo:%.*]])
+    // CODEGEN: #dbg_declare(ptr %dead_first_foo.dbg.spill, [[ARG_dead_first_foo:![0-9]+]], !DIExpression()
+    // OPTIMIZED: #dbg_value(ptr %dead_first_foo, [[ARG_dead_first_foo:![0-9]+]], !DIExpression()
+    // CHECK: #dbg_value(ptr %dead_first_foo, [[VAR_dead_first_v0:![0-9]+]], !DIExpression()
+    // CHECK: %dead_first_v0 = getelementptr{{.*}} i8, ptr %dead_first_foo, i64 16
+    // CODEGEN: #dbg_declare(ptr %dead_first_v0.dbg.spill, [[VAR_dead_first_v0]], !DIExpression()
+    // OPTIMIZED: #dbg_value(ptr %dead_first_v0, [[VAR_dead_first_v0]], !DIExpression()
+    let mut dead_first_v0 = &dead_first_foo.0;
+    dead_first_v0 = &dead_first_foo.2;
+    dead_first_v0
+}
+
+#[unsafe(no_mangle)]
+pub fn fragment(fragment_v1: Foo, mut fragment_v2: Foo) -> Foo {
+    // CHECK-LABEL: define{{( dso_local)?}} void @fragment
+    // CHECK-SAME: (ptr {{.*}}, ptr {{.*}} [[ARG_fragment_v1:%.*]], ptr {{.*}} [[ARG_fragment_v2:%.*]])
+    // CHECK: #dbg_declare(ptr [[ARG_fragment_v1]]
+    // CHECK-NEXT: #dbg_declare(ptr [[ARG_fragment_v2]]
+    // CHECK-NEXT: #dbg_value(ptr [[ARG_fragment_v2]], [[VAR_fragment_f:![0-9]+]], !DIExpression(DW_OP_LLVM_fragment, 0, 64)
+    // CHECK-NEXT: #dbg_value(ptr [[ARG_fragment_v1]], [[VAR_fragment_f:![0-9]+]], !DIExpression(DW_OP_LLVM_fragment, 64, 64)
+    let fragment_f = || {
+        fragment_v2 = fragment_v1;
+    };
+    fragment_v2 = fragment_v1;
+    fragment_v2
+}
+
+#[unsafe(no_mangle)]
+pub fn deref(bar: Bar) -> i32 {
+    // CHECK-LABEL: define{{.*}} i32 @deref
+    // We are unable to represent dereference within this expression.
+    // CHECK: #dbg_value(ptr poison, [[VAR_deref_dead:![0-9]+]], !DIExpression()
+    let deref_dead = &bar.foo.2;
+    bar.a
+}
+
+#[unsafe(no_mangle)]
+fn index(slice: &[i32; 4], idx: usize) -> i32 {
+    // CHECK-LABEL: define{{.*}} i32 @index
+    // CHECK: call void @opaque_fn()
+    opaque_fn();
+    // CHECK: #dbg_value(ptr poison, [[VAR_index_from_var:![0-9]+]], !DIExpression()
+    let index_from_var = &slice[idx];
+    // CHECK: #dbg_value(ptr %slice, [[VAR_const_index_from_start:![0-9]+]], !DIExpression()
+    // CHECK-NEXT: #dbg_value(ptr poison, [[VAR_const_index_from_end:![0-9]+]], !DIExpression()
+    let [ref const_index_from_start, .., ref const_index_from_end] = slice[..] else {
+        return 0;
+    };
+    slice[0]
+}
+
+// CHECK-DAG: [[ref_local_var_scalar]] = !DILocalVariable(name: "ref_local_var_scalar"
+// CHECK-DAG: [[ref_dead_local_var_scalar]] = !DILocalVariable(name: "ref_dead_local_var_scalar"
+// CHECK-DAG: [[ref_local_var_aggregate_4xi8]] = !DILocalVariable(name: "ref_local_var_aggregate_4xi8"
+// CHECK-DAG: [[ref_0_local_var_aggregate_4xi8]] = !DILocalVariable(name: "ref_0_local_var_aggregate_4xi8"
+// CHECK-DAG: [[ref_2_local_var_aggregate_4xi8]] = !DILocalVariable(name: "ref_2_local_var_aggregate_4xi8"
+// CHECK-DAG: [[ref_1_1_local_var_aggregate_i32_array_i8]] = !DILocalVariable(name: "ref_1_1_local_var_aggregate_i32_array_i8"
+// CHECK-DAG: [[ref_2_local_var_aggregate_i32_array_i8]] = !DILocalVariable(name: "ref_2_local_var_aggregate_i32_array_i8"
+
+// CHECK-DAG: [[ref_zst]] = !DILocalVariable(name: "ref_zst"
+// CHECK-DAG: [[ref_zst_ref]] = !DILocalVariable(name: "ref_zst_ref"
+
+// CHECK-DAG: [[ref_scalar]] = !DILocalVariable(name: "ref_scalar"
+// CHECK-DAG: [[ref_scalar_ref]] = !DILocalVariable(name: "ref_scalar_ref"
+// CHECK-DAG: [[ref_0_array_ref]] = !DILocalVariable(name: "ref_0_array_ref"
+// CHECK-DAG: [[ref_1_array_ref]] = !DILocalVariable(name: "ref_1_array_ref"
+// CHECK-DAG: [[ref_1_aggregate_4xi8_ref]] = !DILocalVariable(name: "ref_1_aggregate_4xi8_ref"
+
+// CHECK-DAG: [[ref_aggregate_4xi8]] = !DILocalVariable(name: "ref_aggregate_4xi8"
+// CHECK-DAG: [[ref_0_aggregate_4xi8]] = !DILocalVariable(name: "ref_0_aggregate_4xi8"
+
+// CHECK-DAG: [[ref_tuple_sliceref_scalar]] = !DILocalVariable(name: "ref_tuple_sliceref_scalar"
+// CHECK-DAG: [[ref_1_tuple_sliceref_scalar]] = !DILocalVariable(name: "ref_1_tuple_sliceref_scalar"
+// CHECK-DAG: [[ref_1_array]] = !DILocalVariable(name: "ref_1_array"
+// CHECK-DAG: [[ref_1_typle_i32_i64_i8]] = !DILocalVariable(name: "ref_1_typle_i32_i64_i8"
+// CHECK-DAG: [[ref_simd_i32x4]] = !DILocalVariable(name: "ref_simd_i32x4"
+
+// CHECK-DAG: [[ref_direct_ref]] = !DILocalVariable(name: "ref_direct_ref"
+// CHECK-DAG: [[ref_1_direct_ref]] = !DILocalVariable(name: "ref_1_direct_ref"
+// CHECK-DAG: [[ref_indirect_byval]] = !DILocalVariable(name: "ref_indirect_byval"
+// CHECK-DAG: [[ref_1_indirect_byval]] = !DILocalVariable(name: "ref_1_indirect_byval"
+
+// CHECK-DAG: [[ref_0_tuple_scalar_scalar]] = !DILocalVariable(name: "ref_0_tuple_scalar_scalar"
+// CHECK-DAG: [[ref_0_tuple_ref_scalar]] = !DILocalVariable(name: "ref_0_tuple_ref_scalar"
+// CHECK-DAG: [[ref_1_tuple_ref_scalar]] = !DILocalVariable(name: "ref_1_tuple_ref_scalar"
+// CHECK-DAG: [[ref_0_tuple_arrayref_scalar]] = !DILocalVariable(name: "ref_0_tuple_arrayref_scalar"
+// CHECK-DAG: [[ref_1_tuple_arrayref_scalar]] = !DILocalVariable(name: "ref_1_tuple_arrayref_scalar"
+// CHECK-DAG: [[ref_0_1_tuple_arrayref_scalar]] = !DILocalVariable(name: "ref_0_1_tuple_arrayref_scalar"
+// CHECK-DAG: [[ref_1_1_tuple_scalar_arrayref]] = !DILocalVariable(name: "ref_1_1_tuple_scalar_arrayref"
+// CHECK-DAG: [[ref_1_sliceref]] = !DILocalVariable(name: "ref_1_sliceref"
+
+// CHECK-DAG: [[ARG_dead_first_foo]] = !DILocalVariable(name: "dead_first_foo"
+// CHECK-DAG: [[VAR_dead_first_v0]] = !DILocalVariable(name: "dead_first_v0"
+
+// CHECK-DAG: [[VAR_fragment_f]] = !DILocalVariable(name: "fragment_f"
+
+// CHECK-DAG: [[VAR_deref_dead]] = !DILocalVariable(name: "deref_dead"
+
+// CHECK-DAG: [[VAR_index_from_var]] = !DILocalVariable(name: "index_from_var"
+// CHECK-DAG: [[VAR_const_index_from_start]] = !DILocalVariable(name: "const_index_from_start"
+// CHECK-DAG: [[VAR_const_index_from_end]] = !DILocalVariable(name: "const_index_from_end"
diff --git a/tests/debuginfo/opt/dead_refs.rs b/tests/debuginfo/opt/dead_refs.rs
new file mode 100644
index 00000000000..61e74157334
--- /dev/null
+++ b/tests/debuginfo/opt/dead_refs.rs
@@ -0,0 +1,50 @@
+//@ min-lldb-version: 1800
+//@ min-gdb-version: 13.0
+//@ compile-flags: -g -Copt-level=3
+//@ disable-gdb-pretty-printers
+
+// Checks that we still can access dead variables from debuginfos.
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+// gdb-command:print *ref_v0
+// gdb-check:$1 = 0
+
+// gdb-command:print *ref_v1
+// gdb-check:$2 = 1
+
+// gdb-command:print *ref_v2
+// gdb-check:$3 = 2
+
+// === LLDB TESTS ==================================================================================
+
+// lldb-command:run
+// lldb-command:v *ref_v0
+// lldb-check:[...] 0
+
+// lldb-command:v *ref_v1
+// lldb-check:[...] 1
+
+// lldb-command:v *ref_v2
+// lldb-check:[...] 2
+
+#![allow(unused_variables)]
+
+use std::hint::black_box;
+
+pub struct Foo(i32, i64, i32);
+
+#[inline(never)]
+#[no_mangle]
+fn test_ref(ref_foo: &Foo) -> i32 {
+    let ref_v0 = &ref_foo.0;
+    let ref_v1 = &ref_foo.1;
+    let ref_v2 = &ref_foo.2;
+    ref_foo.0 // #break
+}
+
+fn main() {
+    let foo = black_box(Foo(0, 1, 2));
+    black_box(test_ref(&foo));
+}
diff --git a/tests/mir-opt/dead-store-elimination/cycle.cycle.DeadStoreElimination-initial.diff b/tests/mir-opt/dead-store-elimination/cycle.cycle.DeadStoreElimination-initial.diff
index ff18df1efcf..d584de6861c 100644
--- a/tests/mir-opt/dead-store-elimination/cycle.cycle.DeadStoreElimination-initial.diff
+++ b/tests/mir-opt/dead-store-elimination/cycle.cycle.DeadStoreElimination-initial.diff
@@ -19,10 +19,6 @@
 -         _3 = copy _2;
 -         _2 = copy _1;
 -         _1 = copy _5;
-+         nop;
-+         nop;
-+         nop;
-+         nop;
           _4 = cond() -> [return: bb1, unwind continue];
       }
   
diff --git a/tests/mir-opt/dead-store-elimination/ref.dead_first.DeadStoreElimination-initial.diff b/tests/mir-opt/dead-store-elimination/ref.dead_first.DeadStoreElimination-initial.diff
new file mode 100644
index 00000000000..2a793e24990
--- /dev/null
+++ b/tests/mir-opt/dead-store-elimination/ref.dead_first.DeadStoreElimination-initial.diff
@@ -0,0 +1,30 @@
+- // MIR for `dead_first` before DeadStoreElimination-initial
++ // MIR for `dead_first` after DeadStoreElimination-initial
+  
+  fn dead_first(_1: &Foo) -> &i32 {
+      debug v => _1;
+      let mut _0: &i32;
+      let mut _2: &i32;
+      let mut _3: &i32;
+      let _4: &i32;
+      scope 1 {
+          debug a => _2;
+      }
+  
+      bb0: {
+          StorageLive(_2);
+-         _2 = &((*_1).2: i32);
++         // DBG: _2 = &((*_1).2: i32);
+          StorageLive(_3);
+          StorageLive(_4);
+          _4 = &((*_1).0: i32);
+          _3 = &(*_4);
+          _2 = move _3;
+          StorageDead(_3);
+          StorageDead(_4);
+          _0 = &(*_2);
+          StorageDead(_2);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/dead-store-elimination/ref.rs b/tests/mir-opt/dead-store-elimination/ref.rs
new file mode 100644
index 00000000000..2d3200edab9
--- /dev/null
+++ b/tests/mir-opt/dead-store-elimination/ref.rs
@@ -0,0 +1,31 @@
+//@ test-mir-pass: DeadStoreElimination-initial
+
+pub struct Foo {
+    a: i32,
+    b: i64,
+    c: i32,
+}
+
+// EMIT_MIR ref.tuple.DeadStoreElimination-initial.diff
+pub fn tuple(v: (i32, &Foo)) -> i32 {
+    // CHECK-LABEL: fn tuple
+    // CHECK: debug _dead => [[dead:_[0-9]+]];
+    // CHECK: bb0:
+    // CHECK: DBG: [[dead]] = &((*_3).2: i32)
+    let _dead = &v.1.c;
+    v.1.a
+}
+
+// EMIT_MIR ref.dead_first.DeadStoreElimination-initial.diff
+pub fn dead_first(v: &Foo) -> &i32 {
+    // CHECK-LABEL: fn dead_first
+    // CHECK: debug a => [[var_a:_[0-9]+]];
+    // CHECK: bb0:
+    // CHECK: DBG: [[var_a]] = &((*_1).2: i32)
+    // CHECK: [[tmp_4:_[0-9]+]] = &((*_1).0: i32)
+    // CHECK: [[tmp_3:_[0-9]+]] = &(*[[tmp_4]])
+    // CHECK: [[var_a]] = move [[tmp_3]]
+    let mut a = &v.c;
+    a = &v.a;
+    a
+}
diff --git a/tests/mir-opt/dead-store-elimination/ref.tuple.DeadStoreElimination-initial.diff b/tests/mir-opt/dead-store-elimination/ref.tuple.DeadStoreElimination-initial.diff
new file mode 100644
index 00000000000..0b96569cbe4
--- /dev/null
+++ b/tests/mir-opt/dead-store-elimination/ref.tuple.DeadStoreElimination-initial.diff
@@ -0,0 +1,25 @@
+- // MIR for `tuple` before DeadStoreElimination-initial
++ // MIR for `tuple` after DeadStoreElimination-initial
+  
+  fn tuple(_1: (i32, &Foo)) -> i32 {
+      debug v => _1;
+      let mut _0: i32;
+      let _2: &i32;
+      let mut _3: &Foo;
+      let mut _4: &Foo;
+      scope 1 {
+          debug _dead => _2;
+      }
+  
+      bb0: {
+-         StorageLive(_2);
+-         _3 = deref_copy (_1.1: &Foo);
+-         _2 = &((*_3).2: i32);
++         // DBG: _2 = &((*_3).2: i32);
+          _4 = deref_copy (_1.1: &Foo);
+          _0 = copy ((*_4).0: i32);
+-         StorageDead(_2);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/debuginfo/simplifycfg.drop_debuginfo.SimplifyCfg-final.diff b/tests/mir-opt/debuginfo/simplifycfg.drop_debuginfo.SimplifyCfg-final.diff
new file mode 100644
index 00000000000..d4a73351ee4
--- /dev/null
+++ b/tests/mir-opt/debuginfo/simplifycfg.drop_debuginfo.SimplifyCfg-final.diff
@@ -0,0 +1,26 @@
+- // MIR for `drop_debuginfo` before SimplifyCfg-final
++ // MIR for `drop_debuginfo` after SimplifyCfg-final
+  
+  fn drop_debuginfo(_1: &Foo, _2: bool) -> i32 {
+      debug foo_a => _3;
+      debug foo_b => _4;
+      let mut _0: i32;
+      let mut _3: &i32;
+      let mut _4: &i64;
+  
+      bb0: {
+-         switchInt(copy _2) -> [1: bb1, otherwise: bb2];
+-     }
+- 
+-     bb1: {
+-         // DBG: _3 = &((*_1).0: i32);
+-         goto -> bb2;
+-     }
+- 
+-     bb2: {
+          // DBG: _4 = &((*_1).1: i64);
+          _0 = copy ((*_1).2: i32);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_1.SimplifyCfg-final.diff b/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_1.SimplifyCfg-final.diff
new file mode 100644
index 00000000000..1c12358ad89
--- /dev/null
+++ b/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_1.SimplifyCfg-final.diff
@@ -0,0 +1,30 @@
+- // MIR for `preserve_debuginfo_1` before SimplifyCfg-final
++ // MIR for `preserve_debuginfo_1` after SimplifyCfg-final
+  
+  fn preserve_debuginfo_1(_1: &Foo, _2: &mut bool) -> i32 {
+      debug foo_a => _3;
+      debug foo_b => _4;
+      debug foo_c => _5;
+      let mut _0: i32;
+      let mut _3: &i32;
+      let mut _4: &i64;
+      let mut _5: &i32;
+  
+      bb0: {
+-         goto -> bb1;
+-     }
+- 
+-     bb1: {
+          (*_2) = const true;
+          // DBG: _3 = &((*_1).0: i32);
+-         goto -> bb2;
+-     }
+- 
+-     bb2: {
+          // DBG: _4 = &((*_1).1: i64);
+          _0 = copy ((*_1).2: i32);
+          // DBG: _5 = &((*_1).2: i32);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_2.SimplifyCfg-final.diff b/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_2.SimplifyCfg-final.diff
new file mode 100644
index 00000000000..de8e5612c87
--- /dev/null
+++ b/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_2.SimplifyCfg-final.diff
@@ -0,0 +1,29 @@
+- // MIR for `preserve_debuginfo_2` before SimplifyCfg-final
++ // MIR for `preserve_debuginfo_2` after SimplifyCfg-final
+  
+  fn preserve_debuginfo_2(_1: &Foo) -> i32 {
+      debug foo_a => _2;
+      debug foo_b => _3;
+      debug foo_c => _4;
+      let mut _0: i32;
+      let mut _2: &i32;
+      let mut _3: &i64;
+      let mut _4: &i32;
+  
+      bb0: {
+-         goto -> bb1;
+-     }
+- 
+-     bb1: {
+          // DBG: _2 = &((*_1).0: i32);
+-         goto -> bb2;
+-     }
+- 
+-     bb2: {
+          // DBG: _3 = &((*_1).1: i64);
+          _0 = copy ((*_1).2: i32);
+          // DBG: _4 = &((*_1).2: i32);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_3.SimplifyCfg-final.diff b/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_3.SimplifyCfg-final.diff
new file mode 100644
index 00000000000..11372a262a7
--- /dev/null
+++ b/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_3.SimplifyCfg-final.diff
@@ -0,0 +1,37 @@
+- // MIR for `preserve_debuginfo_3` before SimplifyCfg-final
++ // MIR for `preserve_debuginfo_3` after SimplifyCfg-final
+  
+  fn preserve_debuginfo_3(_1: &Foo, _2: bool) -> i32 {
+      debug foo_a => _3;
+      debug foo_b => _4;
+      debug foo_c => _5;
+      let mut _0: i32;
+      let mut _3: &i32;
+      let mut _4: &i64;
+      let mut _5: &i32;
+  
+      bb0: {
+-         switchInt(copy _2) -> [1: bb1, otherwise: bb2];
++         switchInt(copy _2) -> [1: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+-         // DBG: _3 = &((*_1).0: i32);
+-         goto -> bb3;
+-     }
+- 
+-     bb2: {
+          // DBG: _4 = &((*_1).1: i64);
+          _0 = copy ((*_1).2: i32);
+          return;
+      }
+  
+-     bb3: {
++     bb2: {
++         // DBG: _3 = &((*_1).0: i32);
+          // DBG: _5 = &((*_1).2: i32);
+          _0 = copy ((*_1).0: i32);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_identical_succs.SimplifyCfg-final.diff b/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_identical_succs.SimplifyCfg-final.diff
new file mode 100644
index 00000000000..0c6a75237d8
--- /dev/null
+++ b/tests/mir-opt/debuginfo/simplifycfg.preserve_debuginfo_identical_succs.SimplifyCfg-final.diff
@@ -0,0 +1,29 @@
+- // MIR for `preserve_debuginfo_identical_succs` before SimplifyCfg-final
++ // MIR for `preserve_debuginfo_identical_succs` after SimplifyCfg-final
+  
+  fn preserve_debuginfo_identical_succs(_1: &Foo, _2: bool) -> i32 {
+      debug foo_a => _3;
+      debug foo_b => _4;
+      debug foo_c => _5;
+      let mut _0: i32;
+      let mut _3: &i32;
+      let mut _4: &i64;
+      let mut _5: &i32;
+  
+      bb0: {
+-         switchInt(copy _2) -> [1: bb1, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+          // DBG: _3 = &((*_1).0: i32);
+-         goto -> bb2;
+-     }
+- 
+-     bb2: {
+          // DBG: _4 = &((*_1).1: i64);
+          _0 = copy ((*_1).2: i32);
+          // DBG: _5 = &((*_1).2: i32);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/debuginfo/simplifycfg.rs b/tests/mir-opt/debuginfo/simplifycfg.rs
new file mode 100644
index 00000000000..2bd510fd3b9
--- /dev/null
+++ b/tests/mir-opt/debuginfo/simplifycfg.rs
@@ -0,0 +1,207 @@
+//@ test-mir-pass: SimplifyCfg-final
+//@ compile-flags: -Zmir-enable-passes=+DeadStoreElimination-initial
+
+#![feature(core_intrinsics, custom_mir)]
+#![crate_type = "lib"]
+
+use std::intrinsics::mir::*;
+
+pub struct Foo {
+    a: i32,
+    b: i64,
+    c: i32,
+}
+
+// EMIT_MIR simplifycfg.drop_debuginfo.SimplifyCfg-final.diff
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+pub fn drop_debuginfo(foo: &Foo, c: bool) -> i32 {
+    // CHECK-LABEL: fn drop_debuginfo
+    // CHECK: debug foo_b => [[foo_b:_[0-9]+]];
+    // CHECK: bb0: {
+    // CHECK-NEXT: DBG: [[foo_b]] = &((*_1).1: i64)
+    // CHECK-NEXT: _0 = copy ((*_1).2: i32);
+    // CHECK-NEXT: return;
+    mir! {
+        let _foo_a: &i32;
+        let _foo_b: &i64;
+        debug foo_a => _foo_a;
+        debug foo_b => _foo_b;
+        {
+            match c {
+                true => tmp,
+                _ => ret,
+            }
+        }
+        tmp = {
+            // Because we don't know if `c` is always true, we must drop this debuginfo.
+            _foo_a = &(*foo).a;
+            Goto(ret)
+        }
+        ret = {
+            _foo_b = &(*foo).b;
+            RET = (*foo).c;
+            Return()
+        }
+    }
+}
+
+// EMIT_MIR simplifycfg.preserve_debuginfo_1.SimplifyCfg-final.diff
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+pub fn preserve_debuginfo_1(foo: &Foo, v: &mut bool) -> i32 {
+    // CHECK-LABEL: fn preserve_debuginfo_1
+    // CHECK: debug foo_a => [[foo_a:_[0-9]+]];
+    // CHECK: debug foo_b => [[foo_b:_[0-9]+]];
+    // CHECK: debug foo_c => [[foo_c:_[0-9]+]];
+    // CHECK: bb0: {
+    // CHECK-NEXT: (*_2) = const true;
+    // CHECK-NEXT: DBG: [[foo_a]] = &((*_1).0: i32)
+    // CHECK-NEXT: DBG: [[foo_b]] = &((*_1).1: i64)
+    // CHECK-NEXT: _0 = copy ((*_1).2: i32);
+    // CHECK-NEXT: DBG: [[foo_c]] = &((*_1).2: i32)
+    // CHECK-NEXT: return;
+    mir! {
+        let _foo_a: &i32;
+        let _foo_b: &i64;
+        let _foo_c: &i32;
+        debug foo_a => _foo_a;
+        debug foo_b => _foo_b;
+        debug foo_c => _foo_c;
+        {
+            Goto(tmp)
+        }
+        tmp = {
+            *v = true;
+            _foo_a = &(*foo).a;
+            Goto(ret)
+        }
+        ret = {
+            _foo_b = &(*foo).b;
+            RET = (*foo).c;
+            _foo_c = &(*foo).c;
+            Return()
+        }
+    }
+}
+
+// EMIT_MIR simplifycfg.preserve_debuginfo_2.SimplifyCfg-final.diff
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+pub fn preserve_debuginfo_2(foo: &Foo) -> i32 {
+    // CHECK-LABEL: fn preserve_debuginfo_2
+    // CHECK: debug foo_a => [[foo_a:_[0-9]+]];
+    // CHECK: debug foo_b => [[foo_b:_[0-9]+]];
+    // CHECK: debug foo_c => [[foo_c:_[0-9]+]];
+    // CHECK: bb0: {
+    // CHECK-NEXT: DBG: [[foo_a]] = &((*_1).0: i32)
+    // CHECK-NEXT: DBG: [[foo_b]] = &((*_1).1: i64)
+    // CHECK-NEXT: _0 = copy ((*_1).2: i32);
+    // CHECK-NEXT: DBG: [[foo_c]] = &((*_1).2: i32)
+    // CHECK-NEXT: return;
+    mir! {
+        let _foo_a: &i32;
+        let _foo_b: &i64;
+        let _foo_c: &i32;
+        debug foo_a => _foo_a;
+        debug foo_b => _foo_b;
+        debug foo_c => _foo_c;
+        {
+            Goto(tmp)
+        }
+        tmp = {
+            _foo_a = &(*foo).a;
+            Goto(ret)
+        }
+        ret = {
+            _foo_b = &(*foo).b;
+            RET = (*foo).c;
+            _foo_c = &(*foo).c;
+            Return()
+        }
+    }
+}
+
+// EMIT_MIR simplifycfg.preserve_debuginfo_3.SimplifyCfg-final.diff
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+pub fn preserve_debuginfo_3(foo: &Foo, c: bool) -> i32 {
+    // CHECK-LABEL: fn preserve_debuginfo_3
+    // CHECK: debug foo_a => [[foo_a:_[0-9]+]];
+    // CHECK: debug foo_b => [[foo_b:_[0-9]+]];
+    // CHECK: debug foo_c => [[foo_c:_[0-9]+]];
+    // CHECK: bb0: {
+    // CHECK-NEXT: switchInt(copy _2) -> [1: bb2, otherwise: bb1];
+    // CHECK: bb1: {
+    // CHECK-NEXT: DBG: [[foo_b]] = &((*_1).1: i64)
+    // CHECK-NEXT: _0 = copy ((*_1).2: i32);
+    // CHECK-NEXT: return;
+    // CHECK: bb2: {
+    // CHECK-NEXT: DBG: [[foo_a]] = &((*_1).0: i32)
+    // CHECK-NEXT: DBG: [[foo_c]] = &((*_1).2: i32)
+    // CHECK-NEXT: _0 = copy ((*_1).0: i32);
+    // CHECK-NEXT: return;
+    mir! {
+        let _foo_a: &i32;
+        let _foo_b: &i64;
+        let _foo_c: &i32;
+        debug foo_a => _foo_a;
+        debug foo_b => _foo_b;
+        debug foo_c => _foo_c;
+        {
+            match c {
+                true => tmp,
+                _ => ret,
+            }
+        }
+        tmp = {
+            _foo_a = &(*foo).a;
+            Goto(ret_1)
+        }
+        ret = {
+            _foo_b = &(*foo).b;
+            RET = (*foo).c;
+            Return()
+        }
+        ret_1 = {
+            _foo_c = &(*foo).c;
+            RET = (*foo).a;
+            Return()
+        }
+    }
+}
+
+// EMIT_MIR simplifycfg.preserve_debuginfo_identical_succs.SimplifyCfg-final.diff
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+pub fn preserve_debuginfo_identical_succs(foo: &Foo, c: bool) -> i32 {
+    // CHECK-LABEL: fn preserve_debuginfo_identical_succs
+    // CHECK: debug foo_a => [[foo_a:_[0-9]+]];
+    // CHECK: debug foo_b => [[foo_b:_[0-9]+]];
+    // CHECK: debug foo_c => [[foo_c:_[0-9]+]];
+    // CHECK: bb0: {
+    // CHECK-NEXT: DBG: [[foo_a]] = &((*_1).0: i32)
+    // CHECK-NEXT: DBG: [[foo_b]] = &((*_1).1: i64)
+    // CHECK-NEXT: _0 = copy ((*_1).2: i32);
+    // CHECK-NEXT: DBG: [[foo_c]] = &((*_1).2: i32)
+    // CHECK-NEXT: return;
+    mir! {
+        let _foo_a: &i32;
+        let _foo_b: &i64;
+        let _foo_c: &i32;
+        debug foo_a => _foo_a;
+        debug foo_b => _foo_b;
+        debug foo_c => _foo_c;
+        {
+            match c {
+                true => tmp,
+                _ => tmp,
+            }
+        }
+        tmp = {
+            _foo_a = &(*foo).a;
+            Goto(ret)
+        }
+        ret = {
+            _foo_b = &(*foo).b;
+            RET = (*foo).c;
+            _foo_c = &(*foo).c;
+            Return()
+        }
+    }
+}
diff --git a/tests/mir-opt/inline/inline_shims.drop.Inline.panic-abort.diff b/tests/mir-opt/inline/inline_shims.drop.Inline.panic-abort.diff
index f6c111a2228..9509739413b 100644
--- a/tests/mir-opt/inline/inline_shims.drop.Inline.panic-abort.diff
+++ b/tests/mir-opt/inline/inline_shims.drop.Inline.panic-abort.diff
@@ -84,7 +84,6 @@
           _5 = copy _2;
 -         _0 = drop_in_place::<Option<B>>(move _5) -> [return: bb2, unwind unreachable];
 +         StorageLive(_15);
-+         StorageLive(_16);
 +         _15 = discriminant((*_5));
 +         switchInt(move _15) -> [0: bb5, otherwise: bb6];
       }
@@ -110,7 +109,6 @@
 +     }
 + 
 +     bb5: {
-+         StorageDead(_16);
 +         StorageDead(_15);
           StorageDead(_5);
           return;
diff --git a/tests/mir-opt/inline/inline_shims.drop.Inline.panic-unwind.diff b/tests/mir-opt/inline/inline_shims.drop.Inline.panic-unwind.diff
index 18324276425..34f89da19f5 100644
--- a/tests/mir-opt/inline/inline_shims.drop.Inline.panic-unwind.diff
+++ b/tests/mir-opt/inline/inline_shims.drop.Inline.panic-unwind.diff
@@ -27,13 +27,11 @@
           _5 = copy _2;
 -         _0 = drop_in_place::<Option<B>>(move _5) -> [return: bb2, unwind continue];
 +         StorageLive(_6);
-+         StorageLive(_7);
 +         _6 = discriminant((*_5));
 +         switchInt(move _6) -> [0: bb2, otherwise: bb3];
       }
   
       bb2: {
-+         StorageDead(_7);
 +         StorageDead(_6);
           StorageDead(_5);
           return;
diff --git a/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff b/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff
index 2ae86e2eb8b..0acb33febe5 100644
--- a/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff
+++ b/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff
@@ -129,11 +129,8 @@
           _10 = deref_copy (_1.1: &mut std::task::Context<'_>);
           _9 = &mut (*_10);
 -         _7 = <{async fn body of ActionPermit<'_, T>::perform()} as Future>::poll(move _8, move _9) -> [return: bb3, unwind unreachable];
-+         StorageLive(_11);
-+         StorageLive(_15);
 +         StorageLive(_16);
 +         StorageLive(_25);
-+         StorageLive(_27);
 +         StorageLive(_30);
 +         StorageLive(_31);
 +         StorageLive(_32);
@@ -166,11 +163,8 @@
 +         StorageDead(_32);
 +         StorageDead(_31);
 +         StorageDead(_30);
-+         StorageDead(_27);
 +         StorageDead(_25);
 +         StorageDead(_16);
-+         StorageDead(_15);
-+         StorageDead(_11);
           StorageDead(_9);
           StorageDead(_8);
           StorageDead(_7);
@@ -223,23 +217,15 @@
 +         _22 = &mut (*_23);
 +         StorageDead(_24);
 +         StorageLive(_44);
-+         StorageLive(_45);
 +         StorageLive(_49);
 +         StorageLive(_41);
 +         StorageLive(_42);
-+         StorageLive(_43);
-+         _45 = &mut _19;
-+         StorageLive(_46);
-+         _46 = &mut (_19.0: &mut std::future::Ready<()>);
 +         _44 = copy (_19.0: &mut std::future::Ready<()>);
-+         StorageDead(_46);
-+         _43 = &mut ((*_44).0: std::option::Option<()>);
 +         StorageLive(_47);
 +         _47 = Option::<()>::None;
 +         _42 = copy ((*_44).0: std::option::Option<()>);
 +         ((*_44).0: std::option::Option<()>) = copy _47;
 +         StorageDead(_47);
-+         StorageDead(_43);
 +         StorageLive(_48);
 +         _48 = discriminant(_42);
 +         switchInt(move _48) -> [0: bb11, 1: bb12, otherwise: bb5];
@@ -315,7 +301,6 @@
 +         _18 = Poll::<()>::Ready(move _41);
 +         StorageDead(_41);
 +         StorageDead(_49);
-+         StorageDead(_45);
 +         StorageDead(_44);
 +         StorageDead(_22);
 +         StorageDead(_19);
diff --git a/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff b/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff
index d7ae931aaae..98ee46c29b1 100644
--- a/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff
+++ b/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff
@@ -131,11 +131,8 @@
           _10 = deref_copy (_1.1: &mut std::task::Context<'_>);
           _9 = &mut (*_10);
 -         _7 = <{async fn body of ActionPermit<'_, T>::perform()} as Future>::poll(move _8, move _9) -> [return: bb3, unwind: bb5];
-+         StorageLive(_11);
-+         StorageLive(_15);
 +         StorageLive(_16);
 +         StorageLive(_25);
-+         StorageLive(_27);
 +         StorageLive(_30);
 +         StorageLive(_31);
 +         StorageLive(_32);
@@ -180,11 +177,8 @@
 +         StorageDead(_32);
 +         StorageDead(_31);
 +         StorageDead(_30);
-+         StorageDead(_27);
 +         StorageDead(_25);
 +         StorageDead(_16);
-+         StorageDead(_15);
-+         StorageDead(_11);
           StorageDead(_9);
           StorageDead(_8);
           StorageDead(_7);
@@ -240,23 +234,15 @@
 +         _22 = &mut (*_23);
 +         StorageDead(_24);
 +         StorageLive(_46);
-+         StorageLive(_47);
 +         StorageLive(_51);
 +         StorageLive(_43);
 +         StorageLive(_44);
-+         StorageLive(_45);
-+         _47 = &mut _19;
-+         StorageLive(_48);
-+         _48 = &mut (_19.0: &mut std::future::Ready<()>);
 +         _46 = copy (_19.0: &mut std::future::Ready<()>);
-+         StorageDead(_48);
-+         _45 = &mut ((*_46).0: std::option::Option<()>);
 +         StorageLive(_49);
 +         _49 = Option::<()>::None;
 +         _44 = copy ((*_46).0: std::option::Option<()>);
 +         ((*_46).0: std::option::Option<()>) = copy _49;
 +         StorageDead(_49);
-+         StorageDead(_45);
 +         StorageLive(_50);
 +         _50 = discriminant(_44);
 +         switchInt(move _50) -> [0: bb16, 1: bb17, otherwise: bb7];
@@ -356,7 +342,6 @@
 +         _18 = Poll::<()>::Ready(move _43);
 +         StorageDead(_43);
 +         StorageDead(_51);
-+         StorageDead(_47);
 +         StorageDead(_46);
 +         StorageDead(_22);
 +         StorageDead(_19);
diff --git a/tests/mir-opt/issue_101973.inner.GVN.panic-abort.diff b/tests/mir-opt/issue_101973.inner.GVN.panic-abort.diff
index ac88fe67bb8..3ea7387a48d 100644
--- a/tests/mir-opt/issue_101973.inner.GVN.panic-abort.diff
+++ b/tests/mir-opt/issue_101973.inner.GVN.panic-abort.diff
@@ -30,7 +30,6 @@
           StorageLive(_4);
           StorageLive(_5);
           _5 = copy _1;
-          nop;
 -         StorageLive(_14);
 -         _14 = BitAnd(copy _5, const 255_u32);
 -         _4 = BitOr(const 0_u32, move _14);
diff --git a/tests/mir-opt/issue_101973.inner.GVN.panic-unwind.diff b/tests/mir-opt/issue_101973.inner.GVN.panic-unwind.diff
index 96c3cae2d33..832db856b2c 100644
--- a/tests/mir-opt/issue_101973.inner.GVN.panic-unwind.diff
+++ b/tests/mir-opt/issue_101973.inner.GVN.panic-unwind.diff
@@ -30,7 +30,6 @@
           StorageLive(_4);
           StorageLive(_5);
           _5 = copy _1;
-          nop;
 -         StorageLive(_14);
 -         _14 = BitAnd(copy _5, const 255_u32);
 -         _4 = BitOr(const 0_u32, move _14);
diff --git a/tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-abort.diff b/tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-abort.diff
index 5cf36b9aebf..614d9ad440d 100644
--- a/tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-abort.diff
+++ b/tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-abort.diff
@@ -33,15 +33,9 @@
       }
   
       bb2: {
-          StorageLive(_5);
-          _5 = &(*_2)[0 of 3];
-          StorageLive(_6);
-          _6 = &(*_2)[1 of 3];
-          StorageLive(_7);
-          _7 = &(*_2)[2 of 3];
-          StorageDead(_7);
-          StorageDead(_6);
-          StorageDead(_5);
+          // DBG: _5 = &(*_2)[0 of 3];
+          // DBG: _6 = &(*_2)[1 of 3];
+          // DBG: _7 = &(*_2)[2 of 3];
           StorageDead(_4);
           return;
       }
diff --git a/tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-unwind.diff b/tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-unwind.diff
index 0598a3aa3f1..57a88cf8984 100644
--- a/tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-unwind.diff
+++ b/tests/mir-opt/issue_76432.test.SimplifyComparisonIntegral.panic-unwind.diff
@@ -33,15 +33,9 @@
       }
   
       bb2: {
-          StorageLive(_5);
-          _5 = &(*_2)[0 of 3];
-          StorageLive(_6);
-          _6 = &(*_2)[1 of 3];
-          StorageLive(_7);
-          _7 = &(*_2)[2 of 3];
-          StorageDead(_7);
-          StorageDead(_6);
-          StorageDead(_5);
+          // DBG: _5 = &(*_2)[0 of 3];
+          // DBG: _6 = &(*_2)[1 of 3];
+          // DBG: _7 = &(*_2)[2 of 3];
           StorageDead(_4);
           return;
       }
diff --git a/tests/mir-opt/pre-codegen/clone_as_copy.clone_as_copy.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/clone_as_copy.clone_as_copy.PreCodegen.after.mir
index 34747e5a928..1e6e2ee1b8b 100644
--- a/tests/mir-opt/pre-codegen/clone_as_copy.clone_as_copy.PreCodegen.after.mir
+++ b/tests/mir-opt/pre-codegen/clone_as_copy.clone_as_copy.PreCodegen.after.mir
@@ -12,10 +12,8 @@ fn clone_as_copy(_1: &NestCopy) -> NestCopy {
     }
 
     bb0: {
-        StorageLive(_2);
-        _2 = &((*_1).1: AllCopy);
+        // DBG: _2 = &((*_1).1: AllCopy);
         _0 = copy (*_1);
-        StorageDead(_2);
         return;
     }
 }
diff --git a/tests/mir-opt/pre-codegen/clone_as_copy.enum_clone_as_copy.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/clone_as_copy.enum_clone_as_copy.PreCodegen.after.mir
index e67f362ee04..76bb49bc9c1 100644
--- a/tests/mir-opt/pre-codegen/clone_as_copy.enum_clone_as_copy.PreCodegen.after.mir
+++ b/tests/mir-opt/pre-codegen/clone_as_copy.enum_clone_as_copy.PreCodegen.after.mir
@@ -5,58 +5,28 @@ fn enum_clone_as_copy(_1: &Enum1) -> Enum1 {
     let mut _0: Enum1;
     scope 1 (inlined <Enum1 as Clone>::clone) {
         debug self => _1;
-        let mut _2: isize;
-        let _3: &AllCopy;
-        let _4: &NestCopy;
+        let _2: &AllCopy;
+        let _3: &NestCopy;
         scope 2 {
-            debug __self_0 => _3;
+            debug __self_0 => _2;
             scope 6 (inlined <AllCopy as Clone>::clone) {
-                debug self => _3;
+                debug self => _2;
             }
         }
         scope 3 {
-            debug __self_0 => _4;
+            debug __self_0 => _3;
             scope 4 (inlined <NestCopy as Clone>::clone) {
-                debug self => _4;
-                let _5: &AllCopy;
+                debug self => _3;
+                let _4: &AllCopy;
                 scope 5 (inlined <AllCopy as Clone>::clone) {
-                    debug self => _5;
+                    debug self => _4;
                 }
             }
         }
     }
 
     bb0: {
-        StorageLive(_2);
-        StorageLive(_3);
-        StorageLive(_4);
-        _2 = discriminant((*_1));
-        switchInt(move _2) -> [0: bb1, 1: bb2, otherwise: bb4];
-    }
-
-    bb1: {
-        _3 = &(((*_1) as A).0: AllCopy);
         _0 = copy (*_1);
-        goto -> bb3;
-    }
-
-    bb2: {
-        _4 = &(((*_1) as B).0: NestCopy);
-        StorageLive(_5);
-        _5 = &((((*_1) as B).0: NestCopy).1: AllCopy);
-        StorageDead(_5);
-        _0 = copy (*_1);
-        goto -> bb3;
-    }
-
-    bb3: {
-        StorageDead(_4);
-        StorageDead(_3);
-        StorageDead(_2);
         return;
     }
-
-    bb4: {
-        unreachable;
-    }
 }
diff --git a/tests/mir-opt/pre-codegen/clone_as_copy.rs b/tests/mir-opt/pre-codegen/clone_as_copy.rs
index f5ff1854d38..00f24754d59 100644
--- a/tests/mir-opt/pre-codegen/clone_as_copy.rs
+++ b/tests/mir-opt/pre-codegen/clone_as_copy.rs
@@ -25,19 +25,19 @@ enum Enum1 {
 // EMIT_MIR clone_as_copy.clone_as_copy.PreCodegen.after.mir
 fn clone_as_copy(v: &NestCopy) -> NestCopy {
     // CHECK-LABEL: fn clone_as_copy(
-    // CHECK-NOT: = AllCopy { {{.*}} };
-    // CHECK-NOT: = NestCopy { {{.*}} };
-    // CHECK: _0 = copy (*_1);
-    // CHECK: return;
+    // CHECK: let [[DEAD_VAR:_.*]]: &AllCopy;
+    // CHECK: bb0: {
+    // CHECK-NEXT: DBG: [[DEAD_VAR]] = &((*_1).1: AllCopy)
+    // CHECK-NEXT: _0 = copy (*_1);
+    // CHECK-NEXT: return;
     v.clone()
 }
 
-// FIXME: We can merge into exactly one assignment statement.
 // EMIT_MIR clone_as_copy.enum_clone_as_copy.PreCodegen.after.mir
 fn enum_clone_as_copy(v: &Enum1) -> Enum1 {
     // CHECK-LABEL: fn enum_clone_as_copy(
-    // CHECK-NOT: = Enum1::
-    // CHECK: _0 = copy (*_1);
-    // CHECK: _0 = copy (*_1);
+    // CHECK: bb0: {
+    // CHECK-NEXT: _0 = copy (*_1);
+    // CHECK-NEXT: return;
     v.clone()
 }
diff --git a/tests/mir-opt/pre-codegen/dead_on_invalid_place.invalid_place.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/dead_on_invalid_place.invalid_place.PreCodegen.after.mir
new file mode 100644
index 00000000000..4a2127178fb
--- /dev/null
+++ b/tests/mir-opt/pre-codegen/dead_on_invalid_place.invalid_place.PreCodegen.after.mir
@@ -0,0 +1,13 @@
+// MIR for `invalid_place` after PreCodegen
+
+fn invalid_place(_1: bool) -> bool {
+    debug c1_ref => _2;
+    let mut _0: bool;
+    let mut _2: &bool;
+
+    bb0: {
+        // DBG: _2 = &?;
+        _0 = copy _1;
+        return;
+    }
+}
diff --git a/tests/mir-opt/pre-codegen/dead_on_invalid_place.rs b/tests/mir-opt/pre-codegen/dead_on_invalid_place.rs
new file mode 100644
index 00000000000..5abe9fa43a5
--- /dev/null
+++ b/tests/mir-opt/pre-codegen/dead_on_invalid_place.rs
@@ -0,0 +1,27 @@
+#![feature(core_intrinsics, custom_mir)]
+#![crate_type = "lib"]
+
+use std::intrinsics::mir::*;
+
+// EMIT_MIR dead_on_invalid_place.invalid_place.PreCodegen.after.mir
+#[custom_mir(dialect = "runtime")]
+pub fn invalid_place(c: bool) -> bool {
+    // CHECK-LABEL: fn invalid_place
+    // CHECK: debug c1_ref => [[c1_ref:_[0-9]+]];
+    // CHECK: bb0: {
+    // We cannot read the reference, since `c1` is dead.
+    // CHECK-NEXT: DBG: [[c1_ref]] = &?
+    // CHECK-NEXT: _0 = copy _1;
+    // CHECK-NEXT: return;
+    mir! {
+        let _c1_ref: &bool;
+        let c1: bool;
+        debug c1_ref => _c1_ref;
+        {
+            c1 = c;
+            _c1_ref = &c1;
+            RET = c;
+            Return()
+        }
+    }
+}
diff --git a/tests/mir-opt/pre-codegen/loops.filter_mapped.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/loops.filter_mapped.PreCodegen.after.mir
index 75e8cb1d861..8f30ad30fcc 100644
--- a/tests/mir-opt/pre-codegen/loops.filter_mapped.PreCodegen.after.mir
+++ b/tests/mir-opt/pre-codegen/loops.filter_mapped.PreCodegen.after.mir
@@ -6,20 +6,20 @@ fn filter_mapped(_1: impl Iterator<Item = T>, _2: impl Fn(T) -> Option<U>) -> ()
     let mut _0: ();
     let mut _3: std::iter::FilterMap<impl Iterator<Item = T>, impl Fn(T) -> Option<U>>;
     let mut _4: std::iter::FilterMap<impl Iterator<Item = T>, impl Fn(T) -> Option<U>>;
-    let mut _5: &mut std::iter::FilterMap<impl Iterator<Item = T>, impl Fn(T) -> Option<U>>;
-    let mut _8: std::option::Option<U>;
-    let mut _9: isize;
-    let _11: ();
+    let mut _7: std::option::Option<U>;
+    let mut _8: isize;
+    let _10: ();
+    let mut _11: &mut std::iter::FilterMap<impl Iterator<Item = T>, impl Fn(T) -> Option<U>>;
     scope 1 {
         debug iter => _4;
-        let _10: U;
+        let _9: U;
         scope 2 {
-            debug x => _10;
+            debug x => _9;
         }
         scope 4 (inlined <FilterMap<impl Iterator<Item = T>, impl Fn(T) -> Option<U>> as Iterator>::next) {
-            debug self => _5;
-            let mut _6: &mut impl Iterator<Item = T>;
-            let mut _7: &mut impl Fn(T) -> Option<U>;
+            debug self => _11;
+            let mut _5: &mut impl Iterator<Item = T>;
+            let mut _6: &mut impl Fn(T) -> Option<U>;
         }
     }
     scope 3 (inlined <FilterMap<impl Iterator<Item = T>, impl Fn(T) -> Option<U>> as IntoIterator>::into_iter) {
@@ -37,24 +37,24 @@ fn filter_mapped(_1: impl Iterator<Item = T>, _2: impl Fn(T) -> Option<U>) -> ()
     }
 
     bb2: {
-        StorageLive(_8);
-        _5 = &mut _4;
-        StorageLive(_6);
-        _6 = &mut (_4.0: impl Iterator<Item = T>);
         StorageLive(_7);
-        _7 = &mut (_4.1: impl Fn(T) -> Option<U>);
-        _8 = <impl Iterator<Item = T> as Iterator>::find_map::<U, &mut impl Fn(T) -> Option<U>>(move _6, move _7) -> [return: bb3, unwind: bb9];
+        // DBG: _11 = &_4;
+        StorageLive(_5);
+        _5 = &mut (_4.0: impl Iterator<Item = T>);
+        StorageLive(_6);
+        _6 = &mut (_4.1: impl Fn(T) -> Option<U>);
+        _7 = <impl Iterator<Item = T> as Iterator>::find_map::<U, &mut impl Fn(T) -> Option<U>>(move _5, move _6) -> [return: bb3, unwind: bb9];
     }
 
     bb3: {
-        StorageDead(_7);
         StorageDead(_6);
-        _9 = discriminant(_8);
-        switchInt(move _9) -> [0: bb4, 1: bb6, otherwise: bb8];
+        StorageDead(_5);
+        _8 = discriminant(_7);
+        switchInt(move _8) -> [0: bb4, 1: bb6, otherwise: bb8];
     }
 
     bb4: {
-        StorageDead(_8);
+        StorageDead(_7);
         drop(_4) -> [return: bb5, unwind continue];
     }
 
@@ -64,12 +64,12 @@ fn filter_mapped(_1: impl Iterator<Item = T>, _2: impl Fn(T) -> Option<U>) -> ()
     }
 
     bb6: {
-        _10 = move ((_8 as Some).0: U);
-        _11 = opaque::<U>(move _10) -> [return: bb7, unwind: bb9];
+        _9 = move ((_7 as Some).0: U);
+        _10 = opaque::<U>(move _9) -> [return: bb7, unwind: bb9];
     }
 
     bb7: {
-        StorageDead(_8);
+        StorageDead(_7);
         goto -> bb2;
     }
 
diff --git a/tests/mir-opt/pre-codegen/loops.int_range.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/loops.int_range.PreCodegen.after.mir
index 154cbd3791c..beb7b936ccf 100644
--- a/tests/mir-opt/pre-codegen/loops.int_range.PreCodegen.after.mir
+++ b/tests/mir-opt/pre-codegen/loops.int_range.PreCodegen.after.mir
@@ -5,32 +5,31 @@ fn int_range(_1: usize, _2: usize) -> () {
     debug end => _2;
     let mut _0: ();
     let mut _3: std::ops::Range<usize>;
-    let mut _4: std::ops::Range<usize>;
-    let mut _5: &mut std::ops::Range<usize>;
-    let mut _13: std::option::Option<usize>;
-    let _15: ();
+    let mut _9: std::option::Option<usize>;
+    let _11: ();
+    let mut _12: &mut std::ops::Range<usize>;
     scope 1 {
-        debug iter => _4;
-        let _14: usize;
+        debug iter => _3;
+        let _10: usize;
         scope 2 {
-            debug i => _14;
+            debug i => _10;
         }
         scope 4 (inlined iter::range::<impl Iterator for std::ops::Range<usize>>::next) {
-            debug self => _5;
+            debug self => _12;
             scope 5 (inlined <std::ops::Range<usize> as iter::range::RangeIteratorImpl>::spec_next) {
-                debug self => _5;
-                let mut _6: &usize;
-                let mut _7: &usize;
-                let mut _10: bool;
-                let _11: usize;
-                let mut _12: usize;
+                debug self => _12;
+                let mut _6: bool;
+                let _7: usize;
+                let mut _8: usize;
+                let mut _13: &usize;
+                let mut _14: &usize;
                 scope 6 {
-                    debug old => _11;
+                    debug old => _7;
                     scope 8 (inlined <usize as Step>::forward_unchecked) {
-                        debug start => _11;
+                        debug start => _7;
                         debug n => const 1_usize;
                         scope 9 (inlined #[track_caller] core::num::<impl usize>::unchecked_add) {
-                            debug self => _11;
+                            debug self => _7;
                             debug rhs => const 1_usize;
                             scope 10 (inlined core::ub_checks::check_language_ub) {
                                 scope 11 (inlined core::ub_checks::check_language_ub::runtime) {
@@ -40,10 +39,10 @@ fn int_range(_1: usize, _2: usize) -> () {
                     }
                 }
                 scope 7 (inlined std::cmp::impls::<impl PartialOrd for usize>::lt) {
-                    debug self => _6;
-                    debug other => _7;
-                    let mut _8: usize;
-                    let mut _9: usize;
+                    debug self => _13;
+                    debug other => _14;
+                    let mut _4: usize;
+                    let mut _5: usize;
                 }
             }
         }
@@ -54,54 +53,45 @@ fn int_range(_1: usize, _2: usize) -> () {
 
     bb0: {
         _3 = std::ops::Range::<usize> { start: copy _1, end: copy _2 };
-        StorageLive(_4);
-        _4 = copy _3;
         goto -> bb1;
     }
 
     bb1: {
-        StorageLive(_13);
-        _5 = &mut _4;
-        StorageLive(_10);
-        StorageLive(_6);
-        _6 = &(_4.0: usize);
-        StorageLive(_7);
-        _7 = &(_4.1: usize);
-        StorageLive(_8);
-        _8 = copy (_4.0: usize);
         StorageLive(_9);
-        _9 = copy (_4.1: usize);
-        _10 = Lt(move _8, move _9);
-        StorageDead(_9);
-        StorageDead(_8);
-        switchInt(move _10) -> [0: bb2, otherwise: bb3];
+        // DBG: _12 = &_3;
+        StorageLive(_6);
+        // DBG: _13 = &(_3.0: usize);
+        // DBG: _14 = &(_3.1: usize);
+        StorageLive(_4);
+        _4 = copy (_3.0: usize);
+        StorageLive(_5);
+        _5 = copy (_3.1: usize);
+        _6 = Lt(move _4, move _5);
+        StorageDead(_5);
+        StorageDead(_4);
+        switchInt(move _6) -> [0: bb2, otherwise: bb3];
     }
 
     bb2: {
-        StorageDead(_7);
         StorageDead(_6);
-        StorageDead(_10);
-        StorageDead(_13);
-        StorageDead(_4);
+        StorageDead(_9);
         return;
     }
 
     bb3: {
-        StorageDead(_7);
+        _7 = copy (_3.0: usize);
+        StorageLive(_8);
+        _8 = AddUnchecked(copy _7, const 1_usize);
+        (_3.0: usize) = move _8;
+        StorageDead(_8);
+        _9 = Option::<usize>::Some(copy _7);
         StorageDead(_6);
-        _11 = copy (_4.0: usize);
-        StorageLive(_12);
-        _12 = AddUnchecked(copy _11, const 1_usize);
-        (_4.0: usize) = move _12;
-        StorageDead(_12);
-        _13 = Option::<usize>::Some(copy _11);
-        StorageDead(_10);
-        _14 = copy ((_13 as Some).0: usize);
-        _15 = opaque::<usize>(move _14) -> [return: bb4, unwind continue];
+        _10 = copy ((_9 as Some).0: usize);
+        _11 = opaque::<usize>(move _10) -> [return: bb4, unwind continue];
     }
 
     bb4: {
-        StorageDead(_13);
+        StorageDead(_9);
         goto -> bb1;
     }
 }
diff --git a/tests/mir-opt/pre-codegen/loops.mapped.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/loops.mapped.PreCodegen.after.mir
index d22ea54004c..406c96fc32f 100644
--- a/tests/mir-opt/pre-codegen/loops.mapped.PreCodegen.after.mir
+++ b/tests/mir-opt/pre-codegen/loops.mapped.PreCodegen.after.mir
@@ -6,32 +6,32 @@ fn mapped(_1: impl Iterator<Item = T>, _2: impl Fn(T) -> U) -> () {
     let mut _0: ();
     let mut _3: std::iter::Map<impl Iterator<Item = T>, impl Fn(T) -> U>;
     let mut _4: std::iter::Map<impl Iterator<Item = T>, impl Fn(T) -> U>;
-    let mut _5: &mut std::iter::Map<impl Iterator<Item = T>, impl Fn(T) -> U>;
-    let mut _13: std::option::Option<U>;
-    let _15: ();
+    let mut _12: std::option::Option<U>;
+    let _14: ();
+    let mut _15: &mut std::iter::Map<impl Iterator<Item = T>, impl Fn(T) -> U>;
     scope 1 {
         debug iter => _4;
-        let _14: U;
+        let _13: U;
         scope 2 {
-            debug x => _14;
+            debug x => _13;
         }
         scope 4 (inlined <Map<impl Iterator<Item = T>, impl Fn(T) -> U> as Iterator>::next) {
-            debug self => _5;
-            let mut _6: &mut impl Iterator<Item = T>;
-            let mut _7: std::option::Option<T>;
-            let mut _8: &mut impl Fn(T) -> U;
+            debug self => _15;
+            let mut _5: &mut impl Iterator<Item = T>;
+            let mut _6: std::option::Option<T>;
+            let mut _7: &mut impl Fn(T) -> U;
             scope 5 (inlined Option::<T>::map::<U, &mut impl Fn(T) -> U>) {
-                debug self => _7;
-                debug f => _8;
-                let mut _9: isize;
-                let _10: T;
-                let mut _11: (T,);
-                let mut _12: U;
+                debug self => _6;
+                debug f => _7;
+                let mut _8: isize;
+                let _9: T;
+                let mut _10: (T,);
+                let mut _11: U;
                 scope 6 {
-                    debug x => _10;
+                    debug x => _9;
                     scope 7 (inlined ops::function::impls::<impl FnOnce<(T,)> for &mut impl Fn(T) -> U>::call_once) {
-                        debug self => _8;
-                        debug args => _11;
+                        debug self => _7;
+                        debug args => _10;
                     }
                 }
             }
@@ -52,30 +52,30 @@ fn mapped(_1: impl Iterator<Item = T>, _2: impl Fn(T) -> U) -> () {
     }
 
     bb2: {
-        StorageLive(_13);
-        _5 = &mut _4;
-        StorageLive(_8);
+        StorageLive(_12);
+        // DBG: _15 = &_4;
         StorageLive(_7);
         StorageLive(_6);
-        _6 = &mut (_4.0: impl Iterator<Item = T>);
-        _7 = <impl Iterator<Item = T> as Iterator>::next(move _6) -> [return: bb3, unwind: bb10];
+        StorageLive(_5);
+        _5 = &mut (_4.0: impl Iterator<Item = T>);
+        _6 = <impl Iterator<Item = T> as Iterator>::next(move _5) -> [return: bb3, unwind: bb10];
     }
 
     bb3: {
-        StorageDead(_6);
-        _8 = &mut (_4.1: impl Fn(T) -> U);
+        StorageDead(_5);
+        _7 = &mut (_4.1: impl Fn(T) -> U);
+        StorageLive(_8);
         StorageLive(_9);
-        StorageLive(_10);
-        _9 = discriminant(_7);
-        switchInt(move _9) -> [0: bb4, 1: bb6, otherwise: bb9];
+        _8 = discriminant(_6);
+        switchInt(move _8) -> [0: bb4, 1: bb6, otherwise: bb9];
     }
 
     bb4: {
-        StorageDead(_10);
         StorageDead(_9);
-        StorageDead(_7);
         StorageDead(_8);
-        StorageDead(_13);
+        StorageDead(_6);
+        StorageDead(_7);
+        StorageDead(_12);
         drop(_4) -> [return: bb5, unwind continue];
     }
 
@@ -85,27 +85,27 @@ fn mapped(_1: impl Iterator<Item = T>, _2: impl Fn(T) -> U) -> () {
     }
 
     bb6: {
-        _10 = move ((_7 as Some).0: T);
-        StorageLive(_12);
+        _9 = move ((_6 as Some).0: T);
         StorageLive(_11);
-        _11 = (copy _10,);
-        _12 = <impl Fn(T) -> U as FnMut<(T,)>>::call_mut(move _8, move _11) -> [return: bb7, unwind: bb10];
+        StorageLive(_10);
+        _10 = (copy _9,);
+        _11 = <impl Fn(T) -> U as FnMut<(T,)>>::call_mut(move _7, move _10) -> [return: bb7, unwind: bb10];
     }
 
     bb7: {
-        StorageDead(_11);
-        _13 = Option::<U>::Some(move _12);
-        StorageDead(_12);
         StorageDead(_10);
+        _12 = Option::<U>::Some(move _11);
+        StorageDead(_11);
         StorageDead(_9);
-        StorageDead(_7);
         StorageDead(_8);
-        _14 = move ((_13 as Some).0: U);
-        _15 = opaque::<U>(move _14) -> [return: bb8, unwind: bb10];
+        StorageDead(_6);
+        StorageDead(_7);
+        _13 = move ((_12 as Some).0: U);
+        _14 = opaque::<U>(move _13) -> [return: bb8, unwind: bb10];
     }
 
     bb8: {
-        StorageDead(_13);
+        StorageDead(_12);
         goto -> bb2;
     }
 
diff --git a/tests/mir-opt/pre-codegen/loops.rs b/tests/mir-opt/pre-codegen/loops.rs
index d0b8cc8db7a..952dd8cac60 100644
--- a/tests/mir-opt/pre-codegen/loops.rs
+++ b/tests/mir-opt/pre-codegen/loops.rs
@@ -1,5 +1,6 @@
 // skip-filecheck
 //@ compile-flags: -O -Zmir-opt-level=2 -g
+//@ ignore-std-debug-assertions (debug assertions result in different inlines)
 //@ needs-unwind
 
 #![crate_type = "lib"]
diff --git a/tests/mir-opt/pre-codegen/loops.vec_move.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/loops.vec_move.PreCodegen.after.mir
index e537dd6a28e..66eb1bcfaa6 100644
--- a/tests/mir-opt/pre-codegen/loops.vec_move.PreCodegen.after.mir
+++ b/tests/mir-opt/pre-codegen/loops.vec_move.PreCodegen.after.mir
@@ -3,72 +3,320 @@
 fn vec_move(_1: Vec<impl Sized>) -> () {
     debug v => _1;
     let mut _0: ();
-    let mut _2: std::vec::IntoIter<impl Sized>;
-    let mut _3: std::vec::IntoIter<impl Sized>;
-    let mut _4: &mut std::vec::IntoIter<impl Sized>;
-    let mut _5: std::option::Option<impl Sized>;
-    let mut _6: isize;
-    let _8: ();
+    let mut _22: std::vec::IntoIter<impl Sized>;
+    let mut _23: std::vec::IntoIter<impl Sized>;
+    let mut _24: &mut std::vec::IntoIter<impl Sized>;
+    let mut _25: std::option::Option<impl Sized>;
+    let mut _26: isize;
+    let _28: ();
     scope 1 {
-        debug iter => _3;
-        let _7: impl Sized;
+        debug iter => _23;
+        let _27: impl Sized;
         scope 2 {
-            debug x => _7;
+            debug x => _27;
+        }
+    }
+    scope 3 (inlined <Vec<impl Sized> as IntoIterator>::into_iter) {
+        debug self => _1;
+        let _2: std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
+        let mut _3: *const std::alloc::Global;
+        let mut _8: usize;
+        let mut _10: *mut impl Sized;
+        let mut _11: *const impl Sized;
+        let mut _12: usize;
+        let _29: &std::vec::Vec<impl Sized>;
+        let mut _30: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
+        let mut _31: &alloc::raw_vec::RawVec<impl Sized>;
+        let mut _32: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
+        let _33: &std::vec::Vec<impl Sized>;
+        let mut _34: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
+        let _35: &std::vec::Vec<impl Sized>;
+        let mut _36: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
+        let mut _37: &alloc::raw_vec::RawVec<impl Sized>;
+        let mut _38: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
+        scope 4 {
+            debug me => _2;
+            scope 5 {
+                debug alloc => const ManuallyDrop::<std::alloc::Global> {{ value: std::alloc::Global }};
+                let _6: std::ptr::NonNull<impl Sized>;
+                scope 6 {
+                    debug buf => _6;
+                    let _7: *mut impl Sized;
+                    scope 7 {
+                        debug begin => _7;
+                        scope 8 {
+                            debug end => _11;
+                            let _20: usize;
+                            scope 9 {
+                                debug cap => _20;
+                            }
+                            scope 39 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
+                                debug self => _38;
+                            }
+                            scope 40 (inlined alloc::raw_vec::RawVec::<impl Sized>::capacity) {
+                                debug self => _37;
+                                let mut _19: usize;
+                                let mut _39: &alloc::raw_vec::RawVecInner;
+                                scope 41 (inlined std::mem::size_of::<impl Sized>) {
+                                }
+                                scope 42 (inlined alloc::raw_vec::RawVecInner::capacity) {
+                                    debug self => _39;
+                                    debug elem_size => _19;
+                                    let mut _21: core::num::niche_types::UsizeNoHighBit;
+                                    scope 43 (inlined core::num::niche_types::UsizeNoHighBit::as_inner) {
+                                        debug self => _21;
+                                    }
+                                }
+                            }
+                        }
+                        scope 25 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
+                            debug self => _34;
+                        }
+                        scope 26 (inlined Vec::<impl Sized>::len) {
+                            debug self => _33;
+                            let mut _13: bool;
+                            scope 27 {
+                            }
+                        }
+                        scope 28 (inlined std::ptr::mut_ptr::<impl *mut impl Sized>::wrapping_byte_add) {
+                            debug self => _7;
+                            debug count => _12;
+                            let mut _14: *mut u8;
+                            let mut _18: *mut u8;
+                            scope 29 (inlined std::ptr::mut_ptr::<impl *mut impl Sized>::cast::<u8>) {
+                                debug self => _7;
+                            }
+                            scope 30 (inlined std::ptr::mut_ptr::<impl *mut u8>::wrapping_add) {
+                                debug self => _14;
+                                debug count => _12;
+                                let mut _15: isize;
+                                scope 31 (inlined std::ptr::mut_ptr::<impl *mut u8>::wrapping_offset) {
+                                    debug self => _14;
+                                    debug count => _15;
+                                    let mut _16: *const u8;
+                                    let mut _17: *const u8;
+                                }
+                            }
+                            scope 32 (inlined std::ptr::mut_ptr::<impl *mut u8>::with_metadata_of::<impl Sized>) {
+                                debug self => _18;
+                                debug meta => _5;
+                                scope 33 (inlined std::ptr::metadata::<impl Sized>) {
+                                    debug ptr => _5;
+                                }
+                                scope 34 (inlined std::ptr::from_raw_parts_mut::<impl Sized, ()>) {
+                                }
+                            }
+                        }
+                        scope 35 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
+                            debug self => _36;
+                        }
+                        scope 36 (inlined Vec::<impl Sized>::len) {
+                            debug self => _35;
+                            let mut _9: bool;
+                            scope 37 {
+                            }
+                        }
+                        scope 38 (inlined #[track_caller] std::ptr::mut_ptr::<impl *mut impl Sized>::add) {
+                            debug self => _7;
+                            debug count => _8;
+                        }
+                    }
+                    scope 24 (inlined NonNull::<impl Sized>::as_ptr) {
+                        debug self => _6;
+                    }
+                }
+                scope 17 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
+                    debug self => _32;
+                }
+                scope 18 (inlined alloc::raw_vec::RawVec::<impl Sized>::non_null) {
+                    debug self => _31;
+                    scope 19 (inlined alloc::raw_vec::RawVecInner::non_null::<impl Sized>) {
+                        let mut _4: std::ptr::NonNull<u8>;
+                        scope 20 (inlined Unique::<u8>::cast::<impl Sized>) {
+                            scope 21 (inlined NonNull::<u8>::cast::<impl Sized>) {
+                                let mut _5: *const impl Sized;
+                                scope 22 (inlined NonNull::<u8>::as_ptr) {
+                                }
+                            }
+                        }
+                        scope 23 (inlined Unique::<impl Sized>::as_non_null_ptr) {
+                        }
+                    }
+                }
+            }
+            scope 11 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
+                debug self => _30;
+            }
+            scope 12 (inlined Vec::<impl Sized>::allocator) {
+                debug self => _29;
+                scope 13 (inlined alloc::raw_vec::RawVec::<impl Sized>::allocator) {
+                    scope 14 (inlined alloc::raw_vec::RawVecInner::allocator) {
+                    }
+                }
+            }
+            scope 15 (inlined #[track_caller] std::ptr::read::<std::alloc::Global>) {
+                debug src => _3;
+            }
+            scope 16 (inlined ManuallyDrop::<std::alloc::Global>::new) {
+                debug value => const std::alloc::Global;
+            }
+        }
+        scope 10 (inlined ManuallyDrop::<Vec<impl Sized>>::new) {
+            debug value => _1;
         }
     }
 
     bb0: {
+        StorageLive(_22);
+        StorageLive(_6);
+        StorageLive(_7);
+        StorageLive(_11);
+        StorageLive(_20);
+        StorageLive(_5);
+        StorageLive(_4);
+        StorageLive(_17);
         StorageLive(_2);
-        _2 = <Vec<impl Sized> as IntoIterator>::into_iter(move _1) -> [return: bb1, unwind continue];
+        _2 = ManuallyDrop::<Vec<impl Sized>> { value: copy _1 };
+        StorageLive(_3);
+        // DBG: _30 = &_2;
+        // DBG: _29 = &(_2.0: std::vec::Vec<impl Sized>);
+        _3 = &raw const ((((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner).2: std::alloc::Global);
+        StorageDead(_3);
+        // DBG: _32 = &_2;
+        // DBG: _31 = &((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>);
+        _4 = copy (((((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner).0: std::ptr::Unique<u8>).0: std::ptr::NonNull<u8>);
+        _5 = copy _4 as *const impl Sized (Transmute);
+        _6 = NonNull::<impl Sized> { pointer: copy _5 };
+        _7 = copy _4 as *mut impl Sized (Transmute);
+        switchInt(const <impl Sized as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb1, otherwise: bb2];
     }
 
     bb1: {
-        StorageLive(_3);
-        _3 = move _2;
-        goto -> bb2;
+        StorageLive(_10);
+        StorageLive(_8);
+        // DBG: _36 = &_2;
+        // DBG: _35 = &(_2.0: std::vec::Vec<impl Sized>);
+        _8 = copy ((_2.0: std::vec::Vec<impl Sized>).1: usize);
+        StorageLive(_9);
+        _9 = Le(copy _8, const <impl Sized as std::mem::SizedTypeProperties>::MAX_SLICE_LEN);
+        assume(move _9);
+        StorageDead(_9);
+        _10 = Offset(copy _7, copy _8);
+        _11 = copy _10 as *const impl Sized (PtrToPtr);
+        StorageDead(_8);
+        StorageDead(_10);
+        goto -> bb4;
     }
 
     bb2: {
-        StorageLive(_5);
-        _4 = &mut _3;
-        _5 = <std::vec::IntoIter<impl Sized> as Iterator>::next(move _4) -> [return: bb3, unwind: bb9];
+        StorageLive(_12);
+        // DBG: _34 = &_2;
+        // DBG: _33 = &(_2.0: std::vec::Vec<impl Sized>);
+        _12 = copy ((_2.0: std::vec::Vec<impl Sized>).1: usize);
+        StorageLive(_13);
+        _13 = Le(copy _12, const <impl Sized as std::mem::SizedTypeProperties>::MAX_SLICE_LEN);
+        assume(move _13);
+        StorageDead(_13);
+        StorageLive(_18);
+        StorageLive(_14);
+        _14 = copy _4 as *mut u8 (Transmute);
+        StorageLive(_15);
+        _15 = copy _12 as isize (IntToInt);
+        StorageLive(_16);
+        _16 = copy _4 as *const u8 (Transmute);
+        _17 = arith_offset::<u8>(move _16, move _15) -> [return: bb3, unwind unreachable];
     }
 
     bb3: {
-        _6 = discriminant(_5);
-        switchInt(move _6) -> [0: bb4, 1: bb6, otherwise: bb8];
+        StorageDead(_16);
+        _18 = copy _17 as *mut u8 (PtrToPtr);
+        StorageDead(_15);
+        StorageDead(_14);
+        StorageDead(_18);
+        StorageDead(_12);
+        _11 = copy _17 as *const impl Sized (PtrToPtr);
+        goto -> bb4;
     }
 
     bb4: {
-        StorageDead(_5);
-        drop(_3) -> [return: bb5, unwind continue];
+        // DBG: _38 = &_2;
+        // DBG: _37 = &((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>);
+        // DBG: _39 = &(((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner);
+        StorageLive(_19);
+        _19 = SizeOf(impl Sized);
+        switchInt(move _19) -> [0: bb5, otherwise: bb6];
     }
 
     bb5: {
-        StorageDead(_3);
-        StorageDead(_2);
-        return;
+        _20 = const usize::MAX;
+        goto -> bb7;
     }
 
     bb6: {
-        _7 = move ((_5 as Some).0: impl Sized);
-        _8 = opaque::<impl Sized>(move _7) -> [return: bb7, unwind: bb9];
+        StorageLive(_21);
+        _21 = copy ((((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner).1: core::num::niche_types::UsizeNoHighBit);
+        _20 = copy _21 as usize (Transmute);
+        StorageDead(_21);
+        goto -> bb7;
     }
 
     bb7: {
+        StorageDead(_19);
+        _22 = std::vec::IntoIter::<impl Sized> { buf: copy _6, phantom: const ZeroSized: PhantomData<impl Sized>, cap: move _20, alloc: const ManuallyDrop::<std::alloc::Global> {{ value: std::alloc::Global }}, ptr: copy _6, end: copy _11 };
+        StorageDead(_2);
+        StorageDead(_17);
+        StorageDead(_4);
         StorageDead(_5);
-        goto -> bb2;
+        StorageDead(_20);
+        StorageDead(_11);
+        StorageDead(_7);
+        StorageDead(_6);
+        StorageLive(_23);
+        _23 = move _22;
+        goto -> bb8;
     }
 
     bb8: {
+        StorageLive(_25);
+        _24 = &mut _23;
+        _25 = <std::vec::IntoIter<impl Sized> as Iterator>::next(move _24) -> [return: bb9, unwind: bb15];
+    }
+
+    bb9: {
+        _26 = discriminant(_25);
+        switchInt(move _26) -> [0: bb10, 1: bb12, otherwise: bb14];
+    }
+
+    bb10: {
+        StorageDead(_25);
+        drop(_23) -> [return: bb11, unwind continue];
+    }
+
+    bb11: {
+        StorageDead(_23);
+        StorageDead(_22);
+        return;
+    }
+
+    bb12: {
+        _27 = move ((_25 as Some).0: impl Sized);
+        _28 = opaque::<impl Sized>(move _27) -> [return: bb13, unwind: bb15];
+    }
+
+    bb13: {
+        StorageDead(_25);
+        goto -> bb8;
+    }
+
+    bb14: {
         unreachable;
     }
 
-    bb9 (cleanup): {
-        drop(_3) -> [return: bb10, unwind terminate(cleanup)];
+    bb15 (cleanup): {
+        drop(_23) -> [return: bb16, unwind terminate(cleanup)];
     }
 
-    bb10 (cleanup): {
+    bb16 (cleanup): {
         resume;
     }
 }
diff --git a/tests/mir-opt/pre-codegen/slice_filter.variant_a-{closure#0}.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/slice_filter.variant_a-{closure#0}.PreCodegen.after.mir
index cbdd194afd3..2cab8818296 100644
--- a/tests/mir-opt/pre-codegen/slice_filter.variant_a-{closure#0}.PreCodegen.after.mir
+++ b/tests/mir-opt/pre-codegen/slice_filter.variant_a-{closure#0}.PreCodegen.after.mir
@@ -3,183 +3,134 @@
 fn variant_a::{closure#0}(_1: &mut {closure@$DIR/slice_filter.rs:7:25: 7:39}, _2: &&(usize, usize, usize, usize)) -> bool {
     let mut _0: bool;
     let mut _3: &(usize, usize, usize, usize);
-    let _4: &usize;
-    let _5: &usize;
-    let _6: &usize;
-    let _7: &usize;
-    let mut _8: &&usize;
-    let _9: &usize;
-    let mut _10: &&usize;
-    let mut _13: bool;
-    let mut _14: &&usize;
+    let mut _6: bool;
+    let mut _9: bool;
+    let mut _10: bool;
+    let _13: &usize;
+    let _14: &usize;
     let _15: &usize;
-    let mut _16: &&usize;
-    let mut _19: bool;
+    let _16: &usize;
+    let mut _17: &&usize;
+    let mut _18: &&usize;
+    let mut _19: &&usize;
     let mut _20: &&usize;
-    let _21: &usize;
+    let mut _21: &&usize;
     let mut _22: &&usize;
-    let mut _23: bool;
+    let mut _23: &&usize;
     let mut _24: &&usize;
-    let _25: &usize;
-    let mut _26: &&usize;
     scope 1 {
-        debug a => _4;
-        debug b => _5;
-        debug c => _6;
-        debug d => _7;
+        debug a => _13;
+        debug b => _14;
+        debug c => _15;
+        debug d => _16;
         scope 2 (inlined std::cmp::impls::<impl PartialOrd for &usize>::le) {
-            debug self => _8;
-            debug other => _10;
+            debug self => _17;
+            debug other => _18;
             scope 3 (inlined std::cmp::impls::<impl PartialOrd for usize>::le) {
-                debug self => _4;
-                debug other => _6;
-                let mut _11: usize;
-                let mut _12: usize;
+                debug self => _13;
+                debug other => _15;
+                let mut _4: usize;
+                let mut _5: usize;
             }
         }
         scope 4 (inlined std::cmp::impls::<impl PartialOrd for &usize>::le) {
-            debug self => _14;
-            debug other => _16;
+            debug self => _19;
+            debug other => _20;
             scope 5 (inlined std::cmp::impls::<impl PartialOrd for usize>::le) {
-                debug self => _7;
-                debug other => _5;
-                let mut _17: usize;
-                let mut _18: usize;
+                debug self => _16;
+                debug other => _14;
+                let mut _7: usize;
+                let mut _8: usize;
             }
         }
         scope 6 (inlined std::cmp::impls::<impl PartialOrd for &usize>::le) {
-            debug self => _20;
+            debug self => _21;
             debug other => _22;
             scope 7 (inlined std::cmp::impls::<impl PartialOrd for usize>::le) {
-                debug self => _6;
-                debug other => _4;
+                debug self => _15;
+                debug other => _13;
             }
         }
         scope 8 (inlined std::cmp::impls::<impl PartialOrd for &usize>::le) {
-            debug self => _24;
-            debug other => _26;
+            debug self => _23;
+            debug other => _24;
             scope 9 (inlined std::cmp::impls::<impl PartialOrd for usize>::le) {
-                debug self => _5;
-                debug other => _7;
-                let mut _27: usize;
-                let mut _28: usize;
+                debug self => _14;
+                debug other => _16;
+                let mut _11: usize;
+                let mut _12: usize;
             }
         }
     }
 
     bb0: {
         _3 = copy (*_2);
-        _4 = &((*_3).0: usize);
-        _5 = &((*_3).1: usize);
-        _6 = &((*_3).2: usize);
-        _7 = &((*_3).3: usize);
-        StorageLive(_13);
-        StorageLive(_8);
-        _8 = &_4;
-        StorageLive(_10);
-        StorageLive(_9);
-        _9 = copy _6;
-        _10 = &_9;
-        _11 = copy ((*_3).0: usize);
-        _12 = copy ((*_3).2: usize);
-        _13 = Le(copy _11, copy _12);
-        switchInt(move _13) -> [0: bb1, otherwise: bb2];
+        // DBG: _13 = &((*_3).0: usize);
+        // DBG: _14 = &((*_3).1: usize);
+        // DBG: _15 = &((*_3).2: usize);
+        // DBG: _16 = &((*_3).3: usize);
+        StorageLive(_6);
+        // DBG: _17 = &_13;
+        // DBG: _18 = &?;
+        _4 = copy ((*_3).0: usize);
+        _5 = copy ((*_3).2: usize);
+        _6 = Le(copy _4, copy _5);
+        switchInt(move _6) -> [0: bb2, otherwise: bb1];
     }
 
     bb1: {
-        StorageDead(_9);
-        StorageDead(_10);
+        StorageLive(_9);
+        // DBG: _19 = &_16;
+        // DBG: _20 = &?;
+        StorageLive(_7);
+        _7 = copy ((*_3).3: usize);
+        StorageLive(_8);
+        _8 = copy ((*_3).1: usize);
+        _9 = Le(move _7, move _8);
         StorageDead(_8);
-        goto -> bb4;
+        StorageDead(_7);
+        switchInt(move _9) -> [0: bb2, otherwise: bb6];
     }
 
     bb2: {
-        StorageDead(_9);
-        StorageDead(_10);
-        StorageDead(_8);
-        StorageLive(_19);
-        StorageLive(_14);
-        _14 = &_7;
-        StorageLive(_16);
-        StorageLive(_15);
-        _15 = copy _5;
-        _16 = &_15;
-        StorageLive(_17);
-        _17 = copy ((*_3).3: usize);
-        StorageLive(_18);
-        _18 = copy ((*_3).1: usize);
-        _19 = Le(move _17, move _18);
-        StorageDead(_18);
-        StorageDead(_17);
-        switchInt(move _19) -> [0: bb3, otherwise: bb8];
+        StorageLive(_10);
+        // DBG: _21 = &_15;
+        // DBG: _22 = &?;
+        _10 = Le(copy _5, copy _4);
+        switchInt(move _10) -> [0: bb3, otherwise: bb4];
     }
 
     bb3: {
-        StorageDead(_15);
-        StorageDead(_16);
-        StorageDead(_14);
-        goto -> bb4;
+        _0 = const false;
+        goto -> bb5;
     }
 
     bb4: {
-        StorageLive(_23);
-        StorageLive(_20);
-        _20 = &_6;
-        StorageLive(_22);
-        StorageLive(_21);
-        _21 = copy _4;
-        _22 = &_21;
-        _23 = Le(copy _12, copy _11);
-        switchInt(move _23) -> [0: bb5, otherwise: bb6];
+        // DBG: _23 = &_14;
+        // DBG: _24 = &?;
+        StorageLive(_11);
+        _11 = copy ((*_3).1: usize);
+        StorageLive(_12);
+        _12 = copy ((*_3).3: usize);
+        _0 = Le(move _11, move _12);
+        StorageDead(_12);
+        StorageDead(_11);
+        goto -> bb5;
     }
 
     bb5: {
-        StorageDead(_21);
-        StorageDead(_22);
-        StorageDead(_20);
-        _0 = const false;
+        StorageDead(_10);
         goto -> bb7;
     }
 
     bb6: {
-        StorageDead(_21);
-        StorageDead(_22);
-        StorageDead(_20);
-        StorageLive(_24);
-        _24 = &_5;
-        StorageLive(_26);
-        StorageLive(_25);
-        _25 = copy _7;
-        _26 = &_25;
-        StorageLive(_27);
-        _27 = copy ((*_3).1: usize);
-        StorageLive(_28);
-        _28 = copy ((*_3).3: usize);
-        _0 = Le(move _27, move _28);
-        StorageDead(_28);
-        StorageDead(_27);
-        StorageDead(_25);
-        StorageDead(_26);
-        StorageDead(_24);
+        _0 = const true;
         goto -> bb7;
     }
 
     bb7: {
-        StorageDead(_23);
-        goto -> bb9;
-    }
-
-    bb8: {
-        StorageDead(_15);
-        StorageDead(_16);
-        StorageDead(_14);
-        _0 = const true;
-        goto -> bb9;
-    }
-
-    bb9: {
-        StorageDead(_19);
-        StorageDead(_13);
+        StorageDead(_9);
+        StorageDead(_6);
         return;
     }
 }
diff --git a/tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-abort.mir b/tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-abort.mir
index 0adf268d766..3009be3f9dc 100644
--- a/tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-abort.mir
+++ b/tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-abort.mir
@@ -7,19 +7,87 @@ fn reverse_loop(_1: &[T], _2: impl Fn(&T)) -> () {
     let mut _10: std::slice::Iter<'_, T>;
     let mut _11: std::iter::Rev<std::slice::Iter<'_, T>>;
     let mut _12: std::iter::Rev<std::slice::Iter<'_, T>>;
-    let mut _14: std::option::Option<&T>;
-    let mut _15: isize;
-    let mut _17: &impl Fn(&T);
-    let mut _18: (&T,);
-    let _19: ();
+    let mut _33: std::option::Option<&T>;
+    let mut _35: &impl Fn(&T);
+    let mut _36: (&T,);
+    let _37: ();
     scope 1 {
         debug iter => _12;
-        let _16: &T;
+        let _34: &T;
         scope 2 {
-            debug x => _16;
+            debug x => _34;
         }
         scope 18 (inlined <Rev<std::slice::Iter<'_, T>> as Iterator>::next) {
-            let mut _13: &mut std::slice::Iter<'_, T>;
+            scope 19 (inlined <std::slice::Iter<'_, T> as DoubleEndedIterator>::next_back) {
+                let mut _13: *const T;
+                let mut _18: bool;
+                let mut _19: *const T;
+                let _32: &T;
+                scope 20 {
+                    let _14: std::ptr::NonNull<T>;
+                    let _20: usize;
+                    scope 21 {
+                    }
+                    scope 22 {
+                        scope 25 (inlined <NonNull<T> as PartialEq>::eq) {
+                            let mut _15: std::ptr::NonNull<T>;
+                            let mut _16: *mut T;
+                            let mut _17: *mut T;
+                            scope 26 (inlined NonNull::<T>::as_ptr) {
+                            }
+                            scope 27 (inlined NonNull::<T>::as_ptr) {
+                            }
+                        }
+                    }
+                    scope 23 (inlined std::ptr::const_ptr::<impl *const T>::addr) {
+                        scope 24 (inlined std::ptr::const_ptr::<impl *const T>::cast::<()>) {
+                        }
+                    }
+                }
+                scope 28 (inlined std::slice::Iter::<'_, T>::next_back_unchecked) {
+                    let _26: std::ptr::NonNull<T>;
+                    scope 29 (inlined std::slice::Iter::<'_, T>::pre_dec_end) {
+                        let mut _21: *mut *const T;
+                        let mut _22: *mut std::ptr::NonNull<T>;
+                        let mut _23: std::ptr::NonNull<T>;
+                        let mut _27: *mut *const T;
+                        let mut _28: *mut usize;
+                        let mut _29: usize;
+                        let mut _30: usize;
+                        scope 30 {
+                            scope 31 {
+                            }
+                            scope 32 {
+                                scope 35 (inlined NonNull::<T>::sub) {
+                                    scope 36 (inlined #[track_caller] core::num::<impl isize>::unchecked_neg) {
+                                        scope 37 (inlined core::ub_checks::check_language_ub) {
+                                            scope 38 (inlined core::ub_checks::check_language_ub::runtime) {
+                                            }
+                                        }
+                                    }
+                                    scope 39 (inlined NonNull::<T>::offset) {
+                                        let mut _24: *const T;
+                                        let mut _25: *const T;
+                                        scope 40 (inlined NonNull::<T>::as_ptr) {
+                                        }
+                                    }
+                                }
+                            }
+                            scope 33 (inlined std::ptr::mut_ptr::<impl *mut *const T>::cast::<usize>) {
+                            }
+                            scope 34 (inlined std::ptr::mut_ptr::<impl *mut *const T>::cast::<NonNull<T>>) {
+                            }
+                        }
+                    }
+                    scope 41 (inlined NonNull::<T>::as_ref::<'_>) {
+                        let _31: *const T;
+                        scope 42 (inlined NonNull::<T>::as_ptr) {
+                        }
+                        scope 43 (inlined std::ptr::mut_ptr::<impl *mut T>::cast_const) {
+                        }
+                    }
+                }
+            }
         }
     }
     scope 3 (inlined core::slice::<impl [T]>::iter) {
@@ -105,45 +173,136 @@ fn reverse_loop(_1: &[T], _2: impl Fn(&T)) -> () {
     }
 
     bb4: {
+        StorageLive(_33);
+        StorageLive(_20);
+        StorageLive(_19);
         StorageLive(_14);
-        StorageLive(_13);
-        _13 = &mut (_12.0: std::slice::Iter<'_, T>);
-        _14 = <std::slice::Iter<'_, T> as DoubleEndedIterator>::next_back(move _13) -> [return: bb5, unwind unreachable];
+        StorageLive(_32);
+        StorageLive(_18);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb5, otherwise: bb6];
     }
 
     bb5: {
+        StorageLive(_13);
+        _13 = copy ((_12.0: std::slice::Iter<'_, T>).1: *const T);
+        _14 = copy _13 as std::ptr::NonNull<T> (Transmute);
         StorageDead(_13);
-        _15 = discriminant(_14);
-        switchInt(move _15) -> [0: bb6, 1: bb8, otherwise: bb10];
+        StorageLive(_16);
+        StorageLive(_15);
+        _15 = copy ((_12.0: std::slice::Iter<'_, T>).0: std::ptr::NonNull<T>);
+        _16 = copy _15 as *mut T (Transmute);
+        StorageDead(_15);
+        StorageLive(_17);
+        _17 = copy _14 as *mut T (Transmute);
+        _18 = Eq(copy _16, copy _17);
+        StorageDead(_17);
+        StorageDead(_16);
+        goto -> bb7;
     }
 
     bb6: {
-        StorageDead(_14);
-        StorageDead(_12);
-        drop(_2) -> [return: bb7, unwind unreachable];
+        _19 = copy ((_12.0: std::slice::Iter<'_, T>).1: *const T);
+        _20 = copy _19 as usize (Transmute);
+        _18 = Eq(copy _20, const 0_usize);
+        goto -> bb7;
     }
 
     bb7: {
-        return;
+        switchInt(move _18) -> [0: bb8, otherwise: bb15];
     }
 
     bb8: {
-        _16 = copy ((_14 as Some).0: &T);
-        StorageLive(_17);
-        _17 = &_2;
-        StorageLive(_18);
-        _18 = (copy _16,);
-        _19 = <impl Fn(&T) as Fn<(&T,)>>::call(move _17, move _18) -> [return: bb9, unwind unreachable];
+        StorageLive(_26);
+        StorageLive(_28);
+        StorageLive(_22);
+        StorageLive(_23);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb9, otherwise: bb12];
     }
 
     bb9: {
+        StorageLive(_21);
+        _21 = &raw mut ((_12.0: std::slice::Iter<'_, T>).1: *const T);
+        _22 = copy _21 as *mut std::ptr::NonNull<T> (PtrToPtr);
+        StorageDead(_21);
+        _23 = copy (*_22);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb10, otherwise: bb11];
+    }
+
+    bb10: {
+        StorageLive(_25);
+        StorageLive(_24);
+        _24 = copy _23 as *const T (Transmute);
+        _25 = Offset(copy _24, const -1_isize);
+        StorageDead(_24);
+        _23 = NonNull::<T> { pointer: copy _25 };
+        StorageDead(_25);
+        goto -> bb11;
+    }
+
+    bb11: {
+        (*_22) = move _23;
+        _26 = copy (*_22);
+        goto -> bb13;
+    }
+
+    bb12: {
+        StorageLive(_27);
+        _27 = &raw mut ((_12.0: std::slice::Iter<'_, T>).1: *const T);
+        _28 = copy _27 as *mut usize (PtrToPtr);
+        StorageDead(_27);
+        StorageLive(_30);
+        StorageLive(_29);
+        _29 = copy (*_28);
+        _30 = SubUnchecked(move _29, const 1_usize);
+        StorageDead(_29);
+        (*_28) = move _30;
+        StorageDead(_30);
+        _26 = copy ((_12.0: std::slice::Iter<'_, T>).0: std::ptr::NonNull<T>);
+        goto -> bb13;
+    }
+
+    bb13: {
+        StorageDead(_23);
+        StorageDead(_22);
+        StorageDead(_28);
+        StorageLive(_31);
+        _31 = copy _26 as *const T (Transmute);
+        _32 = &(*_31);
+        StorageDead(_31);
+        StorageDead(_26);
+        _33 = Option::<&T>::Some(copy _32);
         StorageDead(_18);
-        StorageDead(_17);
+        StorageDead(_32);
         StorageDead(_14);
+        StorageDead(_19);
+        StorageDead(_20);
+        _34 = copy ((_33 as Some).0: &T);
+        StorageLive(_35);
+        _35 = &_2;
+        StorageLive(_36);
+        _36 = (copy _34,);
+        _37 = <impl Fn(&T) as Fn<(&T,)>>::call(move _35, move _36) -> [return: bb14, unwind unreachable];
+    }
+
+    bb14: {
+        StorageDead(_36);
+        StorageDead(_35);
+        StorageDead(_33);
         goto -> bb4;
     }
 
-    bb10: {
-        unreachable;
+    bb15: {
+        StorageDead(_18);
+        StorageDead(_32);
+        StorageDead(_14);
+        StorageDead(_19);
+        StorageDead(_20);
+        StorageDead(_33);
+        StorageDead(_12);
+        drop(_2) -> [return: bb16, unwind unreachable];
+    }
+
+    bb16: {
+        return;
     }
 }
diff --git a/tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-unwind.mir b/tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-unwind.mir
index cb0d640d445..e40bff5ea35 100644
--- a/tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-unwind.mir
+++ b/tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-unwind.mir
@@ -7,19 +7,87 @@ fn reverse_loop(_1: &[T], _2: impl Fn(&T)) -> () {
     let mut _10: std::slice::Iter<'_, T>;
     let mut _11: std::iter::Rev<std::slice::Iter<'_, T>>;
     let mut _12: std::iter::Rev<std::slice::Iter<'_, T>>;
-    let mut _14: std::option::Option<&T>;
-    let mut _15: isize;
-    let mut _17: &impl Fn(&T);
-    let mut _18: (&T,);
-    let _19: ();
+    let mut _33: std::option::Option<&T>;
+    let mut _35: &impl Fn(&T);
+    let mut _36: (&T,);
+    let _37: ();
     scope 1 {
         debug iter => _12;
-        let _16: &T;
+        let _34: &T;
         scope 2 {
-            debug x => _16;
+            debug x => _34;
         }
         scope 18 (inlined <Rev<std::slice::Iter<'_, T>> as Iterator>::next) {
-            let mut _13: &mut std::slice::Iter<'_, T>;
+            scope 19 (inlined <std::slice::Iter<'_, T> as DoubleEndedIterator>::next_back) {
+                let mut _13: *const T;
+                let mut _18: bool;
+                let mut _19: *const T;
+                let _32: &T;
+                scope 20 {
+                    let _14: std::ptr::NonNull<T>;
+                    let _20: usize;
+                    scope 21 {
+                    }
+                    scope 22 {
+                        scope 25 (inlined <NonNull<T> as PartialEq>::eq) {
+                            let mut _15: std::ptr::NonNull<T>;
+                            let mut _16: *mut T;
+                            let mut _17: *mut T;
+                            scope 26 (inlined NonNull::<T>::as_ptr) {
+                            }
+                            scope 27 (inlined NonNull::<T>::as_ptr) {
+                            }
+                        }
+                    }
+                    scope 23 (inlined std::ptr::const_ptr::<impl *const T>::addr) {
+                        scope 24 (inlined std::ptr::const_ptr::<impl *const T>::cast::<()>) {
+                        }
+                    }
+                }
+                scope 28 (inlined std::slice::Iter::<'_, T>::next_back_unchecked) {
+                    let _26: std::ptr::NonNull<T>;
+                    scope 29 (inlined std::slice::Iter::<'_, T>::pre_dec_end) {
+                        let mut _21: *mut *const T;
+                        let mut _22: *mut std::ptr::NonNull<T>;
+                        let mut _23: std::ptr::NonNull<T>;
+                        let mut _27: *mut *const T;
+                        let mut _28: *mut usize;
+                        let mut _29: usize;
+                        let mut _30: usize;
+                        scope 30 {
+                            scope 31 {
+                            }
+                            scope 32 {
+                                scope 35 (inlined NonNull::<T>::sub) {
+                                    scope 36 (inlined #[track_caller] core::num::<impl isize>::unchecked_neg) {
+                                        scope 37 (inlined core::ub_checks::check_language_ub) {
+                                            scope 38 (inlined core::ub_checks::check_language_ub::runtime) {
+                                            }
+                                        }
+                                    }
+                                    scope 39 (inlined NonNull::<T>::offset) {
+                                        let mut _24: *const T;
+                                        let mut _25: *const T;
+                                        scope 40 (inlined NonNull::<T>::as_ptr) {
+                                        }
+                                    }
+                                }
+                            }
+                            scope 33 (inlined std::ptr::mut_ptr::<impl *mut *const T>::cast::<usize>) {
+                            }
+                            scope 34 (inlined std::ptr::mut_ptr::<impl *mut *const T>::cast::<NonNull<T>>) {
+                            }
+                        }
+                    }
+                    scope 41 (inlined NonNull::<T>::as_ref::<'_>) {
+                        let _31: *const T;
+                        scope 42 (inlined NonNull::<T>::as_ptr) {
+                        }
+                        scope 43 (inlined std::ptr::mut_ptr::<impl *mut T>::cast_const) {
+                        }
+                    }
+                }
+            }
         }
     }
     scope 3 (inlined core::slice::<impl [T]>::iter) {
@@ -105,53 +173,144 @@ fn reverse_loop(_1: &[T], _2: impl Fn(&T)) -> () {
     }
 
     bb4: {
+        StorageLive(_33);
+        StorageLive(_20);
+        StorageLive(_19);
         StorageLive(_14);
-        StorageLive(_13);
-        _13 = &mut (_12.0: std::slice::Iter<'_, T>);
-        _14 = <std::slice::Iter<'_, T> as DoubleEndedIterator>::next_back(move _13) -> [return: bb5, unwind: bb11];
+        StorageLive(_32);
+        StorageLive(_18);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb5, otherwise: bb6];
     }
 
     bb5: {
+        StorageLive(_13);
+        _13 = copy ((_12.0: std::slice::Iter<'_, T>).1: *const T);
+        _14 = copy _13 as std::ptr::NonNull<T> (Transmute);
         StorageDead(_13);
-        _15 = discriminant(_14);
-        switchInt(move _15) -> [0: bb6, 1: bb8, otherwise: bb10];
+        StorageLive(_16);
+        StorageLive(_15);
+        _15 = copy ((_12.0: std::slice::Iter<'_, T>).0: std::ptr::NonNull<T>);
+        _16 = copy _15 as *mut T (Transmute);
+        StorageDead(_15);
+        StorageLive(_17);
+        _17 = copy _14 as *mut T (Transmute);
+        _18 = Eq(copy _16, copy _17);
+        StorageDead(_17);
+        StorageDead(_16);
+        goto -> bb7;
     }
 
     bb6: {
-        StorageDead(_14);
-        StorageDead(_12);
-        drop(_2) -> [return: bb7, unwind continue];
+        _19 = copy ((_12.0: std::slice::Iter<'_, T>).1: *const T);
+        _20 = copy _19 as usize (Transmute);
+        _18 = Eq(copy _20, const 0_usize);
+        goto -> bb7;
     }
 
     bb7: {
-        return;
+        switchInt(move _18) -> [0: bb8, otherwise: bb17];
     }
 
     bb8: {
-        _16 = copy ((_14 as Some).0: &T);
-        StorageLive(_17);
-        _17 = &_2;
-        StorageLive(_18);
-        _18 = (copy _16,);
-        _19 = <impl Fn(&T) as Fn<(&T,)>>::call(move _17, move _18) -> [return: bb9, unwind: bb11];
+        StorageLive(_26);
+        StorageLive(_28);
+        StorageLive(_22);
+        StorageLive(_23);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb9, otherwise: bb12];
     }
 
     bb9: {
+        StorageLive(_21);
+        _21 = &raw mut ((_12.0: std::slice::Iter<'_, T>).1: *const T);
+        _22 = copy _21 as *mut std::ptr::NonNull<T> (PtrToPtr);
+        StorageDead(_21);
+        _23 = copy (*_22);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb10, otherwise: bb11];
+    }
+
+    bb10: {
+        StorageLive(_25);
+        StorageLive(_24);
+        _24 = copy _23 as *const T (Transmute);
+        _25 = Offset(copy _24, const -1_isize);
+        StorageDead(_24);
+        _23 = NonNull::<T> { pointer: copy _25 };
+        StorageDead(_25);
+        goto -> bb11;
+    }
+
+    bb11: {
+        (*_22) = move _23;
+        _26 = copy (*_22);
+        goto -> bb13;
+    }
+
+    bb12: {
+        StorageLive(_27);
+        _27 = &raw mut ((_12.0: std::slice::Iter<'_, T>).1: *const T);
+        _28 = copy _27 as *mut usize (PtrToPtr);
+        StorageDead(_27);
+        StorageLive(_30);
+        StorageLive(_29);
+        _29 = copy (*_28);
+        _30 = SubUnchecked(move _29, const 1_usize);
+        StorageDead(_29);
+        (*_28) = move _30;
+        StorageDead(_30);
+        _26 = copy ((_12.0: std::slice::Iter<'_, T>).0: std::ptr::NonNull<T>);
+        goto -> bb13;
+    }
+
+    bb13: {
+        StorageDead(_23);
+        StorageDead(_22);
+        StorageDead(_28);
+        StorageLive(_31);
+        _31 = copy _26 as *const T (Transmute);
+        _32 = &(*_31);
+        StorageDead(_31);
+        StorageDead(_26);
+        _33 = Option::<&T>::Some(copy _32);
         StorageDead(_18);
-        StorageDead(_17);
+        StorageDead(_32);
         StorageDead(_14);
-        goto -> bb4;
+        StorageDead(_19);
+        StorageDead(_20);
+        _34 = copy ((_33 as Some).0: &T);
+        StorageLive(_35);
+        _35 = &_2;
+        StorageLive(_36);
+        _36 = (copy _34,);
+        _37 = <impl Fn(&T) as Fn<(&T,)>>::call(move _35, move _36) -> [return: bb14, unwind: bb15];
     }
 
-    bb10: {
-        unreachable;
+    bb14: {
+        StorageDead(_36);
+        StorageDead(_35);
+        StorageDead(_33);
+        goto -> bb4;
     }
 
-    bb11 (cleanup): {
-        drop(_2) -> [return: bb12, unwind terminate(cleanup)];
+    bb15 (cleanup): {
+        drop(_2) -> [return: bb16, unwind terminate(cleanup)];
     }
 
-    bb12 (cleanup): {
+    bb16 (cleanup): {
         resume;
     }
+
+    bb17: {
+        StorageDead(_18);
+        StorageDead(_32);
+        StorageDead(_14);
+        StorageDead(_19);
+        StorageDead(_20);
+        StorageDead(_33);
+        StorageDead(_12);
+        drop(_2) -> [return: bb18, unwind continue];
+    }
+
+    bb18: {
+        return;
+    }
 }
diff --git a/tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-abort.mir b/tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-abort.mir
index 78f96bf4195..62b738c36bf 100644
--- a/tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-abort.mir
+++ b/tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-abort.mir
@@ -3,12 +3,187 @@
 fn slice_iter_mut_next_back(_1: &mut std::slice::IterMut<'_, T>) -> Option<&mut T> {
     debug it => _1;
     let mut _0: std::option::Option<&mut T>;
+    scope 1 (inlined <std::slice::IterMut<'_, T> as DoubleEndedIterator>::next_back) {
+        let mut _2: *mut T;
+        let mut _7: bool;
+        let mut _8: *mut T;
+        let mut _21: &mut T;
+        scope 2 {
+            let _3: std::ptr::NonNull<T>;
+            let _9: usize;
+            scope 3 {
+            }
+            scope 4 {
+                scope 7 (inlined <NonNull<T> as PartialEq>::eq) {
+                    let mut _4: std::ptr::NonNull<T>;
+                    let mut _5: *mut T;
+                    let mut _6: *mut T;
+                    scope 8 (inlined NonNull::<T>::as_ptr) {
+                    }
+                    scope 9 (inlined NonNull::<T>::as_ptr) {
+                    }
+                }
+            }
+            scope 5 (inlined std::ptr::mut_ptr::<impl *mut T>::addr) {
+                scope 6 (inlined std::ptr::mut_ptr::<impl *mut T>::cast::<()>) {
+                }
+            }
+        }
+        scope 10 (inlined std::slice::IterMut::<'_, T>::next_back_unchecked) {
+            let mut _15: std::ptr::NonNull<T>;
+            scope 11 (inlined std::slice::IterMut::<'_, T>::pre_dec_end) {
+                let mut _10: *mut *mut T;
+                let mut _11: *mut std::ptr::NonNull<T>;
+                let mut _12: std::ptr::NonNull<T>;
+                let mut _16: *mut *mut T;
+                let mut _17: *mut usize;
+                let mut _18: usize;
+                let mut _19: usize;
+                scope 12 {
+                    scope 13 {
+                    }
+                    scope 14 {
+                        scope 17 (inlined NonNull::<T>::sub) {
+                            scope 18 (inlined #[track_caller] core::num::<impl isize>::unchecked_neg) {
+                                scope 19 (inlined core::ub_checks::check_language_ub) {
+                                    scope 20 (inlined core::ub_checks::check_language_ub::runtime) {
+                                    }
+                                }
+                            }
+                            scope 21 (inlined NonNull::<T>::offset) {
+                                let mut _13: *const T;
+                                let mut _14: *const T;
+                                scope 22 (inlined NonNull::<T>::as_ptr) {
+                                }
+                            }
+                        }
+                    }
+                    scope 15 (inlined std::ptr::mut_ptr::<impl *mut *mut T>::cast::<usize>) {
+                    }
+                    scope 16 (inlined std::ptr::mut_ptr::<impl *mut *mut T>::cast::<NonNull<T>>) {
+                    }
+                }
+            }
+            scope 23 (inlined NonNull::<T>::as_mut::<'_>) {
+                let mut _20: *mut T;
+                scope 24 (inlined NonNull::<T>::as_ptr) {
+                }
+            }
+        }
+    }
 
     bb0: {
-        _0 = <std::slice::IterMut<'_, T> as DoubleEndedIterator>::next_back(move _1) -> [return: bb1, unwind unreachable];
+        StorageLive(_9);
+        StorageLive(_8);
+        StorageLive(_3);
+        StorageLive(_2);
+        StorageLive(_21);
+        StorageLive(_7);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb1, otherwise: bb2];
     }
 
     bb1: {
+        _2 = copy ((*_1).1: *mut T);
+        _3 = copy _2 as std::ptr::NonNull<T> (Transmute);
+        StorageLive(_5);
+        StorageLive(_4);
+        _4 = copy ((*_1).0: std::ptr::NonNull<T>);
+        _5 = copy _4 as *mut T (Transmute);
+        StorageDead(_4);
+        StorageLive(_6);
+        _6 = copy _3 as *mut T (Transmute);
+        _7 = Eq(copy _5, copy _6);
+        StorageDead(_6);
+        StorageDead(_5);
+        goto -> bb3;
+    }
+
+    bb2: {
+        _8 = copy ((*_1).1: *mut T);
+        _9 = copy _8 as usize (Transmute);
+        _7 = Eq(copy _9, const 0_usize);
+        goto -> bb3;
+    }
+
+    bb3: {
+        switchInt(move _7) -> [0: bb4, otherwise: bb10];
+    }
+
+    bb4: {
+        StorageLive(_15);
+        StorageLive(_17);
+        StorageLive(_11);
+        StorageLive(_12);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb5, otherwise: bb8];
+    }
+
+    bb5: {
+        StorageLive(_10);
+        _10 = &raw mut ((*_1).1: *mut T);
+        _11 = copy _10 as *mut std::ptr::NonNull<T> (PtrToPtr);
+        StorageDead(_10);
+        _12 = copy (*_11);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb6, otherwise: bb7];
+    }
+
+    bb6: {
+        StorageLive(_14);
+        StorageLive(_13);
+        _13 = copy _12 as *const T (Transmute);
+        _14 = Offset(copy _13, const -1_isize);
+        StorageDead(_13);
+        _12 = NonNull::<T> { pointer: copy _14 };
+        StorageDead(_14);
+        goto -> bb7;
+    }
+
+    bb7: {
+        (*_11) = move _12;
+        _15 = copy (*_11);
+        goto -> bb9;
+    }
+
+    bb8: {
+        StorageLive(_16);
+        _16 = &raw mut ((*_1).1: *mut T);
+        _17 = copy _16 as *mut usize (PtrToPtr);
+        StorageDead(_16);
+        StorageLive(_19);
+        StorageLive(_18);
+        _18 = copy (*_17);
+        _19 = SubUnchecked(move _18, const 1_usize);
+        StorageDead(_18);
+        (*_17) = move _19;
+        StorageDead(_19);
+        _15 = copy ((*_1).0: std::ptr::NonNull<T>);
+        goto -> bb9;
+    }
+
+    bb9: {
+        StorageDead(_12);
+        StorageDead(_11);
+        StorageDead(_17);
+        StorageLive(_20);
+        _20 = copy _15 as *mut T (Transmute);
+        _21 = &mut (*_20);
+        StorageDead(_20);
+        StorageDead(_15);
+        _0 = Option::<&mut T>::Some(copy _21);
+        goto -> bb11;
+    }
+
+    bb10: {
+        _0 = const {transmute(0x0000000000000000): Option<&mut T>};
+        goto -> bb11;
+    }
+
+    bb11: {
+        StorageDead(_7);
+        StorageDead(_21);
+        StorageDead(_2);
+        StorageDead(_3);
+        StorageDead(_8);
+        StorageDead(_9);
         return;
     }
 }
diff --git a/tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-unwind.mir b/tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-unwind.mir
index dfe5e206fad..62b738c36bf 100644
--- a/tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-unwind.mir
+++ b/tests/mir-opt/pre-codegen/slice_iter.slice_iter_mut_next_back.PreCodegen.after.panic-unwind.mir
@@ -3,12 +3,187 @@
 fn slice_iter_mut_next_back(_1: &mut std::slice::IterMut<'_, T>) -> Option<&mut T> {
     debug it => _1;
     let mut _0: std::option::Option<&mut T>;
+    scope 1 (inlined <std::slice::IterMut<'_, T> as DoubleEndedIterator>::next_back) {
+        let mut _2: *mut T;
+        let mut _7: bool;
+        let mut _8: *mut T;
+        let mut _21: &mut T;
+        scope 2 {
+            let _3: std::ptr::NonNull<T>;
+            let _9: usize;
+            scope 3 {
+            }
+            scope 4 {
+                scope 7 (inlined <NonNull<T> as PartialEq>::eq) {
+                    let mut _4: std::ptr::NonNull<T>;
+                    let mut _5: *mut T;
+                    let mut _6: *mut T;
+                    scope 8 (inlined NonNull::<T>::as_ptr) {
+                    }
+                    scope 9 (inlined NonNull::<T>::as_ptr) {
+                    }
+                }
+            }
+            scope 5 (inlined std::ptr::mut_ptr::<impl *mut T>::addr) {
+                scope 6 (inlined std::ptr::mut_ptr::<impl *mut T>::cast::<()>) {
+                }
+            }
+        }
+        scope 10 (inlined std::slice::IterMut::<'_, T>::next_back_unchecked) {
+            let mut _15: std::ptr::NonNull<T>;
+            scope 11 (inlined std::slice::IterMut::<'_, T>::pre_dec_end) {
+                let mut _10: *mut *mut T;
+                let mut _11: *mut std::ptr::NonNull<T>;
+                let mut _12: std::ptr::NonNull<T>;
+                let mut _16: *mut *mut T;
+                let mut _17: *mut usize;
+                let mut _18: usize;
+                let mut _19: usize;
+                scope 12 {
+                    scope 13 {
+                    }
+                    scope 14 {
+                        scope 17 (inlined NonNull::<T>::sub) {
+                            scope 18 (inlined #[track_caller] core::num::<impl isize>::unchecked_neg) {
+                                scope 19 (inlined core::ub_checks::check_language_ub) {
+                                    scope 20 (inlined core::ub_checks::check_language_ub::runtime) {
+                                    }
+                                }
+                            }
+                            scope 21 (inlined NonNull::<T>::offset) {
+                                let mut _13: *const T;
+                                let mut _14: *const T;
+                                scope 22 (inlined NonNull::<T>::as_ptr) {
+                                }
+                            }
+                        }
+                    }
+                    scope 15 (inlined std::ptr::mut_ptr::<impl *mut *mut T>::cast::<usize>) {
+                    }
+                    scope 16 (inlined std::ptr::mut_ptr::<impl *mut *mut T>::cast::<NonNull<T>>) {
+                    }
+                }
+            }
+            scope 23 (inlined NonNull::<T>::as_mut::<'_>) {
+                let mut _20: *mut T;
+                scope 24 (inlined NonNull::<T>::as_ptr) {
+                }
+            }
+        }
+    }
 
     bb0: {
-        _0 = <std::slice::IterMut<'_, T> as DoubleEndedIterator>::next_back(move _1) -> [return: bb1, unwind continue];
+        StorageLive(_9);
+        StorageLive(_8);
+        StorageLive(_3);
+        StorageLive(_2);
+        StorageLive(_21);
+        StorageLive(_7);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb1, otherwise: bb2];
     }
 
     bb1: {
+        _2 = copy ((*_1).1: *mut T);
+        _3 = copy _2 as std::ptr::NonNull<T> (Transmute);
+        StorageLive(_5);
+        StorageLive(_4);
+        _4 = copy ((*_1).0: std::ptr::NonNull<T>);
+        _5 = copy _4 as *mut T (Transmute);
+        StorageDead(_4);
+        StorageLive(_6);
+        _6 = copy _3 as *mut T (Transmute);
+        _7 = Eq(copy _5, copy _6);
+        StorageDead(_6);
+        StorageDead(_5);
+        goto -> bb3;
+    }
+
+    bb2: {
+        _8 = copy ((*_1).1: *mut T);
+        _9 = copy _8 as usize (Transmute);
+        _7 = Eq(copy _9, const 0_usize);
+        goto -> bb3;
+    }
+
+    bb3: {
+        switchInt(move _7) -> [0: bb4, otherwise: bb10];
+    }
+
+    bb4: {
+        StorageLive(_15);
+        StorageLive(_17);
+        StorageLive(_11);
+        StorageLive(_12);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb5, otherwise: bb8];
+    }
+
+    bb5: {
+        StorageLive(_10);
+        _10 = &raw mut ((*_1).1: *mut T);
+        _11 = copy _10 as *mut std::ptr::NonNull<T> (PtrToPtr);
+        StorageDead(_10);
+        _12 = copy (*_11);
+        switchInt(const <T as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb6, otherwise: bb7];
+    }
+
+    bb6: {
+        StorageLive(_14);
+        StorageLive(_13);
+        _13 = copy _12 as *const T (Transmute);
+        _14 = Offset(copy _13, const -1_isize);
+        StorageDead(_13);
+        _12 = NonNull::<T> { pointer: copy _14 };
+        StorageDead(_14);
+        goto -> bb7;
+    }
+
+    bb7: {
+        (*_11) = move _12;
+        _15 = copy (*_11);
+        goto -> bb9;
+    }
+
+    bb8: {
+        StorageLive(_16);
+        _16 = &raw mut ((*_1).1: *mut T);
+        _17 = copy _16 as *mut usize (PtrToPtr);
+        StorageDead(_16);
+        StorageLive(_19);
+        StorageLive(_18);
+        _18 = copy (*_17);
+        _19 = SubUnchecked(move _18, const 1_usize);
+        StorageDead(_18);
+        (*_17) = move _19;
+        StorageDead(_19);
+        _15 = copy ((*_1).0: std::ptr::NonNull<T>);
+        goto -> bb9;
+    }
+
+    bb9: {
+        StorageDead(_12);
+        StorageDead(_11);
+        StorageDead(_17);
+        StorageLive(_20);
+        _20 = copy _15 as *mut T (Transmute);
+        _21 = &mut (*_20);
+        StorageDead(_20);
+        StorageDead(_15);
+        _0 = Option::<&mut T>::Some(copy _21);
+        goto -> bb11;
+    }
+
+    bb10: {
+        _0 = const {transmute(0x0000000000000000): Option<&mut T>};
+        goto -> bb11;
+    }
+
+    bb11: {
+        StorageDead(_7);
+        StorageDead(_21);
+        StorageDead(_2);
+        StorageDead(_3);
+        StorageDead(_8);
+        StorageDead(_9);
         return;
     }
 }
diff --git a/tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-abort.mir b/tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-abort.mir
index fe4e2deab87..79aa9c5ae1e 100644
--- a/tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-abort.mir
+++ b/tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-abort.mir
@@ -9,7 +9,7 @@ fn outer(_1: u8) -> u8 {
     }
 
     bb0: {
-        _2 = &_1;                        // scope 0 at $DIR/spans.rs:11:11: 11:13
+        // DBG: _2 = &_1;
         _0 = copy _1;                    // scope 1 at $DIR/spans.rs:15:5: 15:7
         return;                          // scope 0 at $DIR/spans.rs:12:2: 12:2
     }
diff --git a/tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-unwind.mir b/tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-unwind.mir
index fe4e2deab87..79aa9c5ae1e 100644
--- a/tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-unwind.mir
+++ b/tests/mir-opt/pre-codegen/spans.outer.PreCodegen.after.panic-unwind.mir
@@ -9,7 +9,7 @@ fn outer(_1: u8) -> u8 {
     }
 
     bb0: {
-        _2 = &_1;                        // scope 0 at $DIR/spans.rs:11:11: 11:13
+        // DBG: _2 = &_1;
         _0 = copy _1;                    // scope 1 at $DIR/spans.rs:15:5: 15:7
         return;                          // scope 0 at $DIR/spans.rs:12:2: 12:2
     }
diff --git a/tests/ui/extern/extern-types-field-offset.rs b/tests/ui/extern/extern-types-field-offset.rs
index 7a5f36da209..470ae07a0b5 100644
--- a/tests/ui/extern/extern-types-field-offset.rs
+++ b/tests/ui/extern/extern-types-field-offset.rs
@@ -23,12 +23,17 @@ fn main() {
     let x: &Newtype = unsafe { &*(&buf as *const _ as *const Newtype) };
     // Projecting to the newtype works, because it is always at offset 0.
     let field = &x.0;
+    // Avoid being eliminated by DSE.
+    std::hint::black_box(field);
 
     let x: &S = unsafe { &*(&buf as *const _ as *const S) };
     // Accessing sized fields is perfectly fine, even at non-zero offsets.
     let field = &x.i;
+    std::hint::black_box(field);
     let field = &x.j;
+    std::hint::black_box(field);
     // This needs to compute the field offset, but we don't know the type's alignment,
     // so this panics.
     let field = &x.a;
+    std::hint::black_box(field);
 }