Auto merge of #106430 - tmiasko:rm-dead-unwinds, r=cjgillot

Remove dead unwinds before drop elaboration

As a part of drop elaboration, we identify dead unwinds, i.e., unwind
edges on a drop terminators which are known to be unreachable, because
there is no need to drop anything.

Previously, the data flow framework was informed about the dead unwinds,
and it assumed those edges are absent from MIR. Unfortunately, the data
flow framework wasn't consistent in maintaining this assumption.

In particular, if a block was reachable only through a dead unwind edge,
its state was propagated to other blocks still. This became an issue in
the context of change removes DropAndReplace terminator, since it
introduces initialization into cleanup blocks.

To avoid this issue, remove unreachable unwind edges before the drop
elaboration, and elaborate only blocks that remain reachable.

cc `@Zeegomo`

11 files changed, 389 insertions, 402 deletions

diff --git a/compiler/rustc_mir_dataflow/src/framework/direction.rs b/compiler/rustc_mir_dataflow/src/framework/direction.rs
index 077a21fc8af..2ae3ae02fcc 100644
--- a/compiler/rustc_mir_dataflow/src/framework/direction.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/direction.rs
@@ -1,4 +1,3 @@
-use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::{self, BasicBlock, Location, SwitchTargets};
 use rustc_middle::ty::TyCtxt;
 use std::ops::RangeInclusive;
@@ -54,7 +53,6 @@ pub trait Direction {
         analysis: &A,
         tcx: TyCtxt<'tcx>,
         body: &mir::Body<'tcx>,
-        dead_unwinds: Option<&BitSet<BasicBlock>>,
         exit_state: &mut A::Domain,
         block: (BasicBlock, &'_ mir::BasicBlockData<'tcx>),
         propagate: impl FnMut(BasicBlock, &A::Domain),
@@ -221,7 +219,6 @@ impl Direction for Backward {
         analysis: &A,
         _tcx: TyCtxt<'tcx>,
         body: &mir::Body<'tcx>,
-        dead_unwinds: Option<&BitSet<BasicBlock>>,
         exit_state: &mut A::Domain,
         (bb, _bb_data): (BasicBlock, &'_ mir::BasicBlockData<'tcx>),
         mut propagate: impl FnMut(BasicBlock, &A::Domain),
@@ -278,20 +275,6 @@ impl Direction for Backward {
                     }
                 }
 
-                // Ignore dead unwinds.
-                mir::TerminatorKind::Call { cleanup: Some(unwind), .. }
-                | mir::TerminatorKind::Assert { cleanup: Some(unwind), .. }
-                | mir::TerminatorKind::Drop { unwind: Some(unwind), .. }
-                | mir::TerminatorKind::DropAndReplace { unwind: Some(unwind), .. }
-                | mir::TerminatorKind::FalseUnwind { unwind: Some(unwind), .. }
-                | mir::TerminatorKind::InlineAsm { cleanup: Some(unwind), .. }
-                    if unwind == bb =>
-                {
-                    if dead_unwinds.map_or(true, |dead| !dead.contains(pred)) {
-                        propagate(pred, exit_state);
-                    }
-                }
-
                 _ => propagate(pred, exit_state),
             }
         }
@@ -304,7 +287,6 @@ struct BackwardSwitchIntEdgeEffectsApplier<'a, 'tcx, D, F> {
     exit_state: &'a mut D,
     bb: BasicBlock,
     propagate: &'a mut F,
-
     effects_applied: bool,
 }
 
@@ -484,7 +466,6 @@ impl Direction for Forward {
         analysis: &A,
         _tcx: TyCtxt<'tcx>,
         _body: &mir::Body<'tcx>,
-        dead_unwinds: Option<&BitSet<BasicBlock>>,
         exit_state: &mut A::Domain,
         (bb, bb_data): (BasicBlock, &'_ mir::BasicBlockData<'tcx>),
         mut propagate: impl FnMut(BasicBlock, &A::Domain),
@@ -502,9 +483,7 @@ impl Direction for Forward {
             | DropAndReplace { target, unwind, value: _, place: _ }
             | FalseUnwind { real_target: target, unwind } => {
                 if let Some(unwind) = unwind {
-                    if dead_unwinds.map_or(true, |dead| !dead.contains(bb)) {
-                        propagate(unwind, exit_state);
-                    }
+                    propagate(unwind, exit_state);
                 }
 
                 propagate(target, exit_state);
@@ -534,9 +513,7 @@ impl Direction for Forward {
                 fn_span: _,
             } => {
                 if let Some(unwind) = cleanup {
-                    if dead_unwinds.map_or(true, |dead| !dead.contains(bb)) {
-                        propagate(unwind, exit_state);
-                    }
+                    propagate(unwind, exit_state);
                 }
 
                 if let Some(target) = target {
@@ -560,9 +537,7 @@ impl Direction for Forward {
                 cleanup,
             } => {
                 if let Some(unwind) = cleanup {
-                    if dead_unwinds.map_or(true, |dead| !dead.contains(bb)) {
-                        propagate(unwind, exit_state);
-                    }
+                    propagate(unwind, exit_state);
                 }
 
                 if let Some(target) = destination {
diff --git a/compiler/rustc_mir_dataflow/src/framework/engine.rs b/compiler/rustc_mir_dataflow/src/framework/engine.rs
index 6ddbe69e17e..91c3bf0ad21 100644
--- a/compiler/rustc_mir_dataflow/src/framework/engine.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/engine.rs
@@ -12,7 +12,6 @@ use rustc_ast as ast;
 use rustc_data_structures::work_queue::WorkQueue;
 use rustc_graphviz as dot;
 use rustc_hir::def_id::DefId;
-use rustc_index::bit_set::BitSet;
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_middle::mir::{self, traversal, BasicBlock};
 use rustc_middle::mir::{create_dump_file, dump_enabled};
@@ -78,7 +77,6 @@ where
 {
     tcx: TyCtxt<'tcx>,
     body: &'a mir::Body<'tcx>,
-    dead_unwinds: Option<&'a BitSet<BasicBlock>>,
     entry_sets: IndexVec<BasicBlock, A::Domain>,
     pass_name: Option<&'static str>,
     analysis: A,
@@ -154,25 +152,7 @@ where
             bug!("`initialize_start_block` is not yet supported for backward dataflow analyses");
         }
 
-        Engine {
-            analysis,
-            tcx,
-            body,
-            dead_unwinds: None,
-            pass_name: None,
-            entry_sets,
-            apply_trans_for_block,
-        }
-    }
-
-    /// Signals that we do not want dataflow state to propagate across unwind edges for these
-    /// `BasicBlock`s.
-    ///
-    /// You must take care that `dead_unwinds` does not contain a `BasicBlock` that *can* actually
-    /// unwind during execution. Otherwise, your dataflow results will not be correct.
-    pub fn dead_unwinds(mut self, dead_unwinds: &'a BitSet<BasicBlock>) -> Self {
-        self.dead_unwinds = Some(dead_unwinds);
-        self
+        Engine { analysis, tcx, body, pass_name: None, entry_sets, apply_trans_for_block }
     }
 
     /// Adds an identifier to the graphviz output for this particular run of a dataflow analysis.
@@ -190,14 +170,7 @@ where
         A::Domain: DebugWithContext<A>,
     {
         let Engine {
-            analysis,
-            body,
-            dead_unwinds,
-            mut entry_sets,
-            tcx,
-            apply_trans_for_block,
-            pass_name,
-            ..
+            analysis, body, mut entry_sets, tcx, apply_trans_for_block, pass_name, ..
         } = self;
 
         let mut dirty_queue: WorkQueue<BasicBlock> = WorkQueue::with_none(body.basic_blocks.len());
@@ -236,7 +209,6 @@ where
                 &analysis,
                 tcx,
                 body,
-                dead_unwinds,
                 &mut state,
                 (bb, bb_data),
                 |target: BasicBlock, state: &A::Domain| {
diff --git a/compiler/rustc_mir_transform/src/elaborate_drops.rs b/compiler/rustc_mir_transform/src/elaborate_drops.rs
index c2ff8645635..bdfd8dc6e99 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drops.rs
@@ -67,13 +67,11 @@ impl<'tcx> MirPass<'tcx> for ElaborateDrops {
         };
         let un_derefer = UnDerefer { tcx: tcx, derefer_sidetable: side_table };
         let elaborate_patch = {
-            let body = &*body;
             let env = MoveDataParamEnv { move_data, param_env };
-            let dead_unwinds = find_dead_unwinds(tcx, body, &env, &un_derefer);
+            remove_dead_unwinds(tcx, body, &env, &un_derefer);
 
             let inits = MaybeInitializedPlaces::new(tcx, body, &env)
                 .into_engine(tcx, body)
-                .dead_unwinds(&dead_unwinds)
                 .pass_name("elaborate_drops")
                 .iterate_to_fixpoint()
                 .into_results_cursor(body);
@@ -81,11 +79,12 @@ impl<'tcx> MirPass<'tcx> for ElaborateDrops {
             let uninits = MaybeUninitializedPlaces::new(tcx, body, &env)
                 .mark_inactive_variants_as_uninit()
                 .into_engine(tcx, body)
-                .dead_unwinds(&dead_unwinds)
                 .pass_name("elaborate_drops")
                 .iterate_to_fixpoint()
                 .into_results_cursor(body);
 
+            let reachable = traversal::reachable_as_bitset(body);
+
             ElaborateDropsCtxt {
                 tcx,
                 body,
@@ -94,6 +93,7 @@ impl<'tcx> MirPass<'tcx> for ElaborateDrops {
                 drop_flags: Default::default(),
                 patch: MirPatch::new(body),
                 un_derefer: un_derefer,
+                reachable,
             }
             .elaborate()
         };
@@ -102,22 +102,21 @@ impl<'tcx> MirPass<'tcx> for ElaborateDrops {
     }
 }
 
-/// Returns the set of basic blocks whose unwind edges are known
-/// to not be reachable, because they are `drop` terminators
+/// Removes unwind edges which are known to be unreachable, because they are in `drop` terminators
 /// that can't drop anything.
-fn find_dead_unwinds<'tcx>(
+fn remove_dead_unwinds<'tcx>(
     tcx: TyCtxt<'tcx>,
-    body: &Body<'tcx>,
+    body: &mut Body<'tcx>,
     env: &MoveDataParamEnv<'tcx>,
     und: &UnDerefer<'tcx>,
-) -> BitSet<BasicBlock> {
-    debug!("find_dead_unwinds({:?})", body.span);
+) {
+    debug!("remove_dead_unwinds({:?})", body.span);
     // We only need to do this pass once, because unwind edges can only
     // reach cleanup blocks, which can't have unwind edges themselves.
-    let mut dead_unwinds = BitSet::new_empty(body.basic_blocks.len());
+    let mut dead_unwinds = Vec::new();
     let mut flow_inits = MaybeInitializedPlaces::new(tcx, body, &env)
         .into_engine(tcx, body)
-        .pass_name("find_dead_unwinds")
+        .pass_name("remove_dead_unwinds")
         .iterate_to_fixpoint()
         .into_results_cursor(body);
     for (bb, bb_data) in body.basic_blocks.iter_enumerated() {
@@ -129,16 +128,16 @@ fn find_dead_unwinds<'tcx>(
             _ => continue,
         };
 
-        debug!("find_dead_unwinds @ {:?}: {:?}", bb, bb_data);
+        debug!("remove_dead_unwinds @ {:?}: {:?}", bb, bb_data);
 
         let LookupResult::Exact(path) = env.move_data.rev_lookup.find(place.as_ref()) else {
-            debug!("find_dead_unwinds: has parent; skipping");
+            debug!("remove_dead_unwinds: has parent; skipping");
             continue;
         };
 
         flow_inits.seek_before_primary_effect(body.terminator_loc(bb));
         debug!(
-            "find_dead_unwinds @ {:?}: path({:?})={:?}; init_data={:?}",
+            "remove_dead_unwinds @ {:?}: path({:?})={:?}; init_data={:?}",
             bb,
             place,
             path,
@@ -150,13 +149,22 @@ fn find_dead_unwinds<'tcx>(
             maybe_live |= flow_inits.contains(child);
         });
 
-        debug!("find_dead_unwinds @ {:?}: maybe_live={}", bb, maybe_live);
+        debug!("remove_dead_unwinds @ {:?}: maybe_live={}", bb, maybe_live);
         if !maybe_live {
-            dead_unwinds.insert(bb);
+            dead_unwinds.push(bb);
         }
     }
 
-    dead_unwinds
+    if dead_unwinds.is_empty() {
+        return;
+    }
+
+    let basic_blocks = body.basic_blocks.as_mut();
+    for &bb in dead_unwinds.iter() {
+        if let Some(unwind) = basic_blocks[bb].terminator_mut().unwind_mut() {
+            *unwind = None;
+        }
+    }
 }
 
 struct InitializationData<'mir, 'tcx> {
@@ -290,6 +298,7 @@ struct ElaborateDropsCtxt<'a, 'tcx> {
     drop_flags: FxHashMap<MovePathIndex, Local>,
     patch: MirPatch<'tcx>,
     un_derefer: UnDerefer<'tcx>,
+    reachable: BitSet<BasicBlock>,
 }
 
 impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
@@ -329,6 +338,9 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
 
     fn collect_drop_flags(&mut self) {
         for (bb, data) in self.body.basic_blocks.iter_enumerated() {
+            if !self.reachable.contains(bb) {
+                continue;
+            }
             let terminator = data.terminator();
             let place = match terminator.kind {
                 TerminatorKind::Drop { ref place, .. }
@@ -384,6 +396,9 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
 
     fn elaborate_drops(&mut self) {
         for (bb, data) in self.body.basic_blocks.iter_enumerated() {
+            if !self.reachable.contains(bb) {
+                continue;
+            }
             let loc = Location { block: bb, statement_index: data.statements.len() };
             let terminator = data.terminator();
 
@@ -541,6 +556,9 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
 
     fn drop_flags_for_fn_rets(&mut self) {
         for (bb, data) in self.body.basic_blocks.iter_enumerated() {
+            if !self.reachable.contains(bb) {
+                continue;
+            }
             if let TerminatorKind::Call {
                 destination, target: Some(tgt), cleanup: Some(_), ..
             } = data.terminator().kind
@@ -576,6 +594,9 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
         // clobbered before they are read.
 
         for (bb, data) in self.body.basic_blocks.iter_enumerated() {
+            if !self.reachable.contains(bb) {
+                continue;
+            }
             debug!("drop_flags_for_locs({:?})", data);
             for i in 0..(data.statements.len() + 1) {
                 debug!("drop_flag_for_locs: stmt {}", i);
diff --git a/tests/mir-opt/issue_41110.main.ElaborateDrops.after.mir b/tests/mir-opt/issue_41110.main.ElaborateDrops.after.mir
deleted file mode 100644
index c2ea3ac502f..00000000000
--- a/tests/mir-opt/issue_41110.main.ElaborateDrops.after.mir
+++ /dev/null
@@ -1,70 +0,0 @@
-// MIR for `main` after ElaborateDrops
-
-fn main() -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/issue_41110.rs:+0:11: +0:11
-    let _1: ();                          // in scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
-    let mut _2: S;                       // in scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
-    let mut _3: S;                       // in scope 0 at $DIR/issue_41110.rs:+1:21: +1:27
-    let mut _4: S;                       // in scope 0 at $DIR/issue_41110.rs:+1:21: +1:22
-    let mut _5: bool;                    // in scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
-    scope 1 {
-        debug x => _1;                   // in scope 1 at $DIR/issue_41110.rs:+1:9: +1:10
-    }
-
-    bb0: {
-        _5 = const false;                // scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
-        StorageLive(_1);                 // scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
-        StorageLive(_2);                 // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
-        _5 = const true;                 // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
-        _2 = S;                          // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
-        StorageLive(_3);                 // scope 0 at $DIR/issue_41110.rs:+1:21: +1:27
-        StorageLive(_4);                 // scope 0 at $DIR/issue_41110.rs:+1:21: +1:22
-        _4 = S;                          // scope 0 at $DIR/issue_41110.rs:+1:21: +1:22
-        _3 = S::id(move _4) -> [return: bb1, unwind: bb4]; // scope 0 at $DIR/issue_41110.rs:+1:21: +1:27
-                                         // mir::Constant
-                                         // + span: $DIR/issue_41110.rs:8:23: 8:25
-                                         // + literal: Const { ty: fn(S) -> S {S::id}, val: Value(<ZST>) }
-    }
-
-    bb1: {
-        StorageDead(_4);                 // scope 0 at $DIR/issue_41110.rs:+1:26: +1:27
-        _5 = const false;                // scope 0 at $DIR/issue_41110.rs:+1:13: +1:28
-        _1 = S::other(move _2, move _3) -> [return: bb2, unwind: bb3]; // scope 0 at $DIR/issue_41110.rs:+1:13: +1:28
-                                         // mir::Constant
-                                         // + span: $DIR/issue_41110.rs:8:15: 8:20
-                                         // + literal: Const { ty: fn(S, S) {S::other}, val: Value(<ZST>) }
-    }
-
-    bb2: {
-        StorageDead(_3);                 // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
-        _5 = const false;                // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
-        StorageDead(_2);                 // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
-        _0 = const ();                   // scope 0 at $DIR/issue_41110.rs:+0:11: +2:2
-        StorageDead(_1);                 // scope 0 at $DIR/issue_41110.rs:+2:1: +2:2
-        return;                          // scope 0 at $DIR/issue_41110.rs:+2:2: +2:2
-    }
-
-    bb3 (cleanup): {
-        goto -> bb5;                     // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
-    }
-
-    bb4 (cleanup): {
-        goto -> bb5;                     // scope 0 at $DIR/issue_41110.rs:+1:26: +1:27
-    }
-
-    bb5 (cleanup): {
-        goto -> bb8;                     // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
-    }
-
-    bb6 (cleanup): {
-        resume;                          // scope 0 at $DIR/issue_41110.rs:+0:1: +2:2
-    }
-
-    bb7 (cleanup): {
-        drop(_2) -> bb6;                 // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
-    }
-
-    bb8 (cleanup): {
-        switchInt(_5) -> [0: bb6, otherwise: bb7]; // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
-    }
-}
diff --git a/tests/mir-opt/issue_41110.main.ElaborateDrops.diff b/tests/mir-opt/issue_41110.main.ElaborateDrops.diff
new file mode 100644
index 00000000000..7ac75b51a37
--- /dev/null
+++ b/tests/mir-opt/issue_41110.main.ElaborateDrops.diff
@@ -0,0 +1,75 @@
+- // MIR for `main` before ElaborateDrops
++ // MIR for `main` after ElaborateDrops
+  
+  fn main() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/issue_41110.rs:+0:11: +0:11
+      let _1: ();                          // in scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
+      let mut _2: S;                       // in scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
+      let mut _3: S;                       // in scope 0 at $DIR/issue_41110.rs:+1:21: +1:27
+      let mut _4: S;                       // in scope 0 at $DIR/issue_41110.rs:+1:21: +1:22
++     let mut _5: bool;                    // in scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
+      scope 1 {
+          debug x => _1;                   // in scope 1 at $DIR/issue_41110.rs:+1:9: +1:10
+      }
+  
+      bb0: {
++         _5 = const false;                // scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
+          StorageLive(_1);                 // scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
+          StorageLive(_2);                 // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
++         _5 = const true;                 // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
+          _2 = S;                          // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
+          StorageLive(_3);                 // scope 0 at $DIR/issue_41110.rs:+1:21: +1:27
+          StorageLive(_4);                 // scope 0 at $DIR/issue_41110.rs:+1:21: +1:22
+          _4 = S;                          // scope 0 at $DIR/issue_41110.rs:+1:21: +1:22
+          _3 = S::id(move _4) -> [return: bb1, unwind: bb4]; // scope 0 at $DIR/issue_41110.rs:+1:21: +1:27
+                                           // mir::Constant
+                                           // + span: $DIR/issue_41110.rs:8:23: 8:25
+                                           // + literal: Const { ty: fn(S) -> S {S::id}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
+          StorageDead(_4);                 // scope 0 at $DIR/issue_41110.rs:+1:26: +1:27
++         _5 = const false;                // scope 0 at $DIR/issue_41110.rs:+1:13: +1:28
+          _1 = S::other(move _2, move _3) -> [return: bb2, unwind: bb3]; // scope 0 at $DIR/issue_41110.rs:+1:13: +1:28
+                                           // mir::Constant
+                                           // + span: $DIR/issue_41110.rs:8:15: 8:20
+                                           // + literal: Const { ty: fn(S, S) {S::other}, val: Value(<ZST>) }
+      }
+  
+      bb2: {
+          StorageDead(_3);                 // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
++         _5 = const false;                // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
+          StorageDead(_2);                 // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
+          _0 = const ();                   // scope 0 at $DIR/issue_41110.rs:+0:11: +2:2
+          StorageDead(_1);                 // scope 0 at $DIR/issue_41110.rs:+2:1: +2:2
+          return;                          // scope 0 at $DIR/issue_41110.rs:+2:2: +2:2
+      }
+  
+      bb3 (cleanup): {
+-         drop(_3) -> bb5;                 // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
++         goto -> bb5;                     // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
+      }
+  
+      bb4 (cleanup): {
+-         drop(_4) -> bb5;                 // scope 0 at $DIR/issue_41110.rs:+1:26: +1:27
++         goto -> bb5;                     // scope 0 at $DIR/issue_41110.rs:+1:26: +1:27
+      }
+  
+      bb5 (cleanup): {
+-         drop(_2) -> bb6;                 // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
++         goto -> bb8;                     // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
+      }
+  
+      bb6 (cleanup): {
+          resume;                          // scope 0 at $DIR/issue_41110.rs:+0:1: +2:2
++     }
++ 
++     bb7 (cleanup): {
++         drop(_2) -> bb6;                 // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
++     }
++ 
++     bb8 (cleanup): {
++         switchInt(_5) -> [0: bb6, otherwise: bb7]; // scope 0 at $DIR/issue_41110.rs:+1:27: +1:28
+      }
+  }
+  
diff --git a/tests/mir-opt/issue_41110.rs b/tests/mir-opt/issue_41110.rs
index 638dc601ec8..e1067ce53e4 100644
--- a/tests/mir-opt/issue_41110.rs
+++ b/tests/mir-opt/issue_41110.rs
@@ -3,14 +3,14 @@
 // check that we don't emit multiple drop flags when they are not needed.
 
 
-// EMIT_MIR issue_41110.main.ElaborateDrops.after.mir
+// EMIT_MIR issue_41110.main.ElaborateDrops.diff
 fn main() {
     let x = S.other(S.id());
 }
 
 // no_mangle to make sure this gets instantiated even in an executable.
 #[no_mangle]
-// EMIT_MIR issue_41110.test.ElaborateDrops.after.mir
+// EMIT_MIR issue_41110.test.ElaborateDrops.diff
 pub fn test() {
     let u = S;
     let mut v = S;
diff --git a/tests/mir-opt/issue_41110.test.ElaborateDrops.after.mir b/tests/mir-opt/issue_41110.test.ElaborateDrops.after.mir
deleted file mode 100644
index 82989c3f071..00000000000
--- a/tests/mir-opt/issue_41110.test.ElaborateDrops.after.mir
+++ /dev/null
@@ -1,101 +0,0 @@
-// MIR for `test` after ElaborateDrops
-
-fn test() -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/issue_41110.rs:+0:15: +0:15
-    let _1: S;                           // in scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
-    let _3: ();                          // in scope 0 at $DIR/issue_41110.rs:+3:5: +3:12
-    let mut _4: S;                       // in scope 0 at $DIR/issue_41110.rs:+3:10: +3:11
-    let mut _5: S;                       // in scope 0 at $DIR/issue_41110.rs:+4:9: +4:10
-    let mut _6: bool;                    // in scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
-    scope 1 {
-        debug u => _1;                   // in scope 1 at $DIR/issue_41110.rs:+1:9: +1:10
-        let mut _2: S;                   // in scope 1 at $DIR/issue_41110.rs:+2:9: +2:14
-        scope 2 {
-            debug v => _2;               // in scope 2 at $DIR/issue_41110.rs:+2:9: +2:14
-        }
-    }
-
-    bb0: {
-        _6 = const false;                // scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
-        StorageLive(_1);                 // scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
-        _6 = const true;                 // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
-        _1 = S;                          // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
-        StorageLive(_2);                 // scope 1 at $DIR/issue_41110.rs:+2:9: +2:14
-        _2 = S;                          // scope 1 at $DIR/issue_41110.rs:+2:17: +2:18
-        StorageLive(_3);                 // scope 2 at $DIR/issue_41110.rs:+3:5: +3:12
-        StorageLive(_4);                 // scope 2 at $DIR/issue_41110.rs:+3:10: +3:11
-        _4 = move _2;                    // scope 2 at $DIR/issue_41110.rs:+3:10: +3:11
-        _3 = std::mem::drop::<S>(move _4) -> [return: bb1, unwind: bb7]; // scope 2 at $DIR/issue_41110.rs:+3:5: +3:12
-                                         // mir::Constant
-                                         // + span: $DIR/issue_41110.rs:17:5: 17:9
-                                         // + literal: Const { ty: fn(S) {std::mem::drop::<S>}, val: Value(<ZST>) }
-    }
-
-    bb1: {
-        StorageDead(_4);                 // scope 2 at $DIR/issue_41110.rs:+3:11: +3:12
-        StorageDead(_3);                 // scope 2 at $DIR/issue_41110.rs:+3:12: +3:13
-        StorageLive(_5);                 // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
-        _6 = const false;                // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
-        _5 = move _1;                    // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
-        goto -> bb12;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-    }
-
-    bb2: {
-        goto -> bb3;                     // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
-    }
-
-    bb3: {
-        StorageDead(_5);                 // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
-        _0 = const ();                   // scope 0 at $DIR/issue_41110.rs:+0:15: +5:2
-        drop(_2) -> [return: bb4, unwind: bb9]; // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
-    }
-
-    bb4: {
-        StorageDead(_2);                 // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
-        goto -> bb5;                     // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
-    }
-
-    bb5: {
-        _6 = const false;                // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
-        StorageDead(_1);                 // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
-        return;                          // scope 0 at $DIR/issue_41110.rs:+5:2: +5:2
-    }
-
-    bb6 (cleanup): {
-        goto -> bb8;                     // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
-    }
-
-    bb7 (cleanup): {
-        goto -> bb8;                     // scope 2 at $DIR/issue_41110.rs:+3:11: +3:12
-    }
-
-    bb8 (cleanup): {
-        goto -> bb9;                     // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
-    }
-
-    bb9 (cleanup): {
-        goto -> bb14;                    // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
-    }
-
-    bb10 (cleanup): {
-        resume;                          // scope 0 at $DIR/issue_41110.rs:+0:1: +5:2
-    }
-
-    bb11 (cleanup): {
-        _2 = move _5;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-        goto -> bb6;                     // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-    }
-
-    bb12: {
-        _2 = move _5;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-        goto -> bb2;                     // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-    }
-
-    bb13 (cleanup): {
-        drop(_1) -> bb10;                // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
-    }
-
-    bb14 (cleanup): {
-        switchInt(_6) -> [0: bb10, otherwise: bb13]; // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
-    }
-}
diff --git a/tests/mir-opt/issue_41110.test.ElaborateDrops.diff b/tests/mir-opt/issue_41110.test.ElaborateDrops.diff
new file mode 100644
index 00000000000..79e3d073be5
--- /dev/null
+++ b/tests/mir-opt/issue_41110.test.ElaborateDrops.diff
@@ -0,0 +1,109 @@
+- // MIR for `test` before ElaborateDrops
++ // MIR for `test` after ElaborateDrops
+  
+  fn test() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/issue_41110.rs:+0:15: +0:15
+      let _1: S;                           // in scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
+      let _3: ();                          // in scope 0 at $DIR/issue_41110.rs:+3:5: +3:12
+      let mut _4: S;                       // in scope 0 at $DIR/issue_41110.rs:+3:10: +3:11
+      let mut _5: S;                       // in scope 0 at $DIR/issue_41110.rs:+4:9: +4:10
++     let mut _6: bool;                    // in scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
+      scope 1 {
+          debug u => _1;                   // in scope 1 at $DIR/issue_41110.rs:+1:9: +1:10
+          let mut _2: S;                   // in scope 1 at $DIR/issue_41110.rs:+2:9: +2:14
+          scope 2 {
+              debug v => _2;               // in scope 2 at $DIR/issue_41110.rs:+2:9: +2:14
+          }
+      }
+  
+      bb0: {
++         _6 = const false;                // scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
+          StorageLive(_1);                 // scope 0 at $DIR/issue_41110.rs:+1:9: +1:10
++         _6 = const true;                 // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
+          _1 = S;                          // scope 0 at $DIR/issue_41110.rs:+1:13: +1:14
+          StorageLive(_2);                 // scope 1 at $DIR/issue_41110.rs:+2:9: +2:14
+          _2 = S;                          // scope 1 at $DIR/issue_41110.rs:+2:17: +2:18
+          StorageLive(_3);                 // scope 2 at $DIR/issue_41110.rs:+3:5: +3:12
+          StorageLive(_4);                 // scope 2 at $DIR/issue_41110.rs:+3:10: +3:11
+          _4 = move _2;                    // scope 2 at $DIR/issue_41110.rs:+3:10: +3:11
+          _3 = std::mem::drop::<S>(move _4) -> [return: bb1, unwind: bb7]; // scope 2 at $DIR/issue_41110.rs:+3:5: +3:12
+                                           // mir::Constant
+                                           // + span: $DIR/issue_41110.rs:17:5: 17:9
+                                           // + literal: Const { ty: fn(S) {std::mem::drop::<S>}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
+          StorageDead(_4);                 // scope 2 at $DIR/issue_41110.rs:+3:11: +3:12
+          StorageDead(_3);                 // scope 2 at $DIR/issue_41110.rs:+3:12: +3:13
+          StorageLive(_5);                 // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
++         _6 = const false;                // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
+          _5 = move _1;                    // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
+-         replace(_2 <- move _5) -> [return: bb2, unwind: bb6]; // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
++         goto -> bb12;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
+      }
+  
+      bb2: {
+-         drop(_5) -> [return: bb3, unwind: bb8]; // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
++         goto -> bb3;                     // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
+      }
+  
+      bb3: {
+          StorageDead(_5);                 // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
+          _0 = const ();                   // scope 0 at $DIR/issue_41110.rs:+0:15: +5:2
+          drop(_2) -> [return: bb4, unwind: bb9]; // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
+      }
+  
+      bb4: {
+          StorageDead(_2);                 // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
+-         drop(_1) -> bb5;                 // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
++         goto -> bb5;                     // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
+      }
+  
+      bb5: {
++         _6 = const false;                // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
+          StorageDead(_1);                 // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
+          return;                          // scope 0 at $DIR/issue_41110.rs:+5:2: +5:2
+      }
+  
+      bb6 (cleanup): {
+          drop(_5) -> bb8;                 // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
+      }
+  
+      bb7 (cleanup): {
+-         drop(_4) -> bb8;                 // scope 2 at $DIR/issue_41110.rs:+3:11: +3:12
++         goto -> bb8;                     // scope 2 at $DIR/issue_41110.rs:+3:11: +3:12
+      }
+  
+      bb8 (cleanup): {
+-         drop(_2) -> bb9;                 // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
++         goto -> bb9;                     // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
+      }
+  
+      bb9 (cleanup): {
+-         drop(_1) -> bb10;                // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
++         goto -> bb14;                    // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
+      }
+  
+      bb10 (cleanup): {
+          resume;                          // scope 0 at $DIR/issue_41110.rs:+0:1: +5:2
++     }
++ 
++     bb11 (cleanup): {
++         _2 = move _5;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
++         goto -> bb10;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
++     }
++ 
++     bb12: {
++         _2 = move _5;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
++         goto -> bb2;                     // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
++     }
++ 
++     bb13 (cleanup): {
++         drop(_1) -> bb10;                // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
++     }
++ 
++     bb14 (cleanup): {
++         switchInt(_6) -> [0: bb10, otherwise: bb13]; // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
+      }
+  }
+  
diff --git a/tests/mir-opt/issue_41888.main.ElaborateDrops.after.mir b/tests/mir-opt/issue_41888.main.ElaborateDrops.after.mir
deleted file mode 100644
index 00504273245..00000000000
--- a/tests/mir-opt/issue_41888.main.ElaborateDrops.after.mir
+++ /dev/null
@@ -1,152 +0,0 @@
-// MIR for `main` after ElaborateDrops
-
-fn main() -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/issue_41888.rs:+0:11: +0:11
-    let _1: E;                           // in scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
-    let mut _2: bool;                    // in scope 0 at $DIR/issue_41888.rs:+2:8: +2:14
-    let mut _3: E;                       // in scope 0 at $DIR/issue_41888.rs:+3:13: +3:20
-    let mut _4: K;                       // in scope 0 at $DIR/issue_41888.rs:+3:18: +3:19
-    let mut _5: isize;                   // in scope 0 at $DIR/issue_41888.rs:+4:16: +4:24
-    let mut _7: bool;                    // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    let mut _8: bool;                    // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    let mut _9: bool;                    // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    let mut _10: isize;                  // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    let mut _11: isize;                  // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    scope 1 {
-        debug e => _1;                   // in scope 1 at $DIR/issue_41888.rs:+1:9: +1:10
-        scope 2 {
-            debug _k => _6;              // in scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
-            let _6: K;                   // in scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
-        }
-    }
-
-    bb0: {
-        _9 = const false;                // scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
-        _7 = const false;                // scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
-        _8 = const false;                // scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
-        StorageLive(_1);                 // scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
-        StorageLive(_2);                 // scope 1 at $DIR/issue_41888.rs:+2:8: +2:14
-        _2 = cond() -> [return: bb1, unwind: bb11]; // scope 1 at $DIR/issue_41888.rs:+2:8: +2:14
-                                         // mir::Constant
-                                         // + span: $DIR/issue_41888.rs:8:8: 8:12
-                                         // + literal: Const { ty: fn() -> bool {cond}, val: Value(<ZST>) }
-    }
-
-    bb1: {
-        switchInt(move _2) -> [0: bb7, otherwise: bb2]; // scope 1 at $DIR/issue_41888.rs:+2:8: +2:14
-    }
-
-    bb2: {
-        StorageLive(_3);                 // scope 1 at $DIR/issue_41888.rs:+3:13: +3:20
-        StorageLive(_4);                 // scope 1 at $DIR/issue_41888.rs:+3:18: +3:19
-        _4 = K;                          // scope 1 at $DIR/issue_41888.rs:+3:18: +3:19
-        _3 = E::F(move _4);              // scope 1 at $DIR/issue_41888.rs:+3:13: +3:20
-        StorageDead(_4);                 // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
-        goto -> bb14;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-    }
-
-    bb3: {
-        goto -> bb4;                     // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
-    }
-
-    bb4: {
-        StorageDead(_3);                 // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
-        _5 = discriminant(_1);           // scope 2 at $DIR/issue_41888.rs:+4:16: +4:24
-        switchInt(move _5) -> [0: bb5, otherwise: bb6]; // scope 2 at $DIR/issue_41888.rs:+4:16: +4:24
-    }
-
-    bb5: {
-        StorageLive(_6);                 // scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
-        _9 = const false;                // scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
-        _6 = move ((_1 as F).0: K);      // scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
-        _0 = const ();                   // scope 2 at $DIR/issue_41888.rs:+4:29: +7:10
-        StorageDead(_6);                 // scope 1 at $DIR/issue_41888.rs:+7:9: +7:10
-        goto -> bb8;                     // scope 1 at $DIR/issue_41888.rs:+4:9: +7:10
-    }
-
-    bb6: {
-        _0 = const ();                   // scope 1 at $DIR/issue_41888.rs:+7:10: +7:10
-        goto -> bb8;                     // scope 1 at $DIR/issue_41888.rs:+4:9: +7:10
-    }
-
-    bb7: {
-        _0 = const ();                   // scope 1 at $DIR/issue_41888.rs:+8:6: +8:6
-        goto -> bb8;                     // scope 1 at $DIR/issue_41888.rs:+2:5: +8:6
-    }
-
-    bb8: {
-        StorageDead(_2);                 // scope 1 at $DIR/issue_41888.rs:+8:5: +8:6
-        goto -> bb20;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-
-    bb9: {
-        _7 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-        _8 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-        _9 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-        StorageDead(_1);                 // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-        return;                          // scope 0 at $DIR/issue_41888.rs:+9:2: +9:2
-    }
-
-    bb10 (cleanup): {
-        goto -> bb11;                    // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
-    }
-
-    bb11 (cleanup): {
-        goto -> bb12;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-
-    bb12 (cleanup): {
-        resume;                          // scope 0 at $DIR/issue_41888.rs:+0:1: +9:2
-    }
-
-    bb13 (cleanup): {
-        _7 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-        _8 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-        _9 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-        _1 = move _3;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-        goto -> bb10;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-    }
-
-    bb14: {
-        _7 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-        _8 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-        _9 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-        _1 = move _3;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-        goto -> bb3;                     // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-    }
-
-    bb15: {
-        _7 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-        goto -> bb9;                     // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-
-    bb16 (cleanup): {
-        goto -> bb12;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-
-    bb17: {
-        drop(_1) -> [return: bb15, unwind: bb12]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-
-    bb18 (cleanup): {
-        drop(_1) -> bb12;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-
-    bb19: {
-        _10 = discriminant(_1);          // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-        switchInt(move _10) -> [0: bb15, otherwise: bb17]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-
-    bb20: {
-        switchInt(_7) -> [0: bb15, otherwise: bb19]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-
-    bb21 (cleanup): {
-        _11 = discriminant(_1);          // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-        switchInt(move _11) -> [0: bb16, otherwise: bb18]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-
-    bb22 (cleanup): {
-        switchInt(_7) -> [0: bb12, otherwise: bb21]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-    }
-}
diff --git a/tests/mir-opt/issue_41888.main.ElaborateDrops.diff b/tests/mir-opt/issue_41888.main.ElaborateDrops.diff
new file mode 100644
index 00000000000..257f0b1e6e8
--- /dev/null
+++ b/tests/mir-opt/issue_41888.main.ElaborateDrops.diff
@@ -0,0 +1,158 @@
+- // MIR for `main` before ElaborateDrops
++ // MIR for `main` after ElaborateDrops
+  
+  fn main() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/issue_41888.rs:+0:11: +0:11
+      let _1: E;                           // in scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
+      let mut _2: bool;                    // in scope 0 at $DIR/issue_41888.rs:+2:8: +2:14
+      let mut _3: E;                       // in scope 0 at $DIR/issue_41888.rs:+3:13: +3:20
+      let mut _4: K;                       // in scope 0 at $DIR/issue_41888.rs:+3:18: +3:19
+      let mut _5: isize;                   // in scope 0 at $DIR/issue_41888.rs:+4:16: +4:24
++     let mut _7: bool;                    // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     let mut _8: bool;                    // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     let mut _9: bool;                    // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     let mut _10: isize;                  // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     let mut _11: isize;                  // in scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
+      scope 1 {
+          debug e => _1;                   // in scope 1 at $DIR/issue_41888.rs:+1:9: +1:10
+          scope 2 {
+              debug _k => _6;              // in scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
+              let _6: K;                   // in scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
+          }
+      }
+  
+      bb0: {
++         _9 = const false;                // scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
++         _7 = const false;                // scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
++         _8 = const false;                // scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
+          StorageLive(_1);                 // scope 0 at $DIR/issue_41888.rs:+1:9: +1:10
+          StorageLive(_2);                 // scope 1 at $DIR/issue_41888.rs:+2:8: +2:14
+          _2 = cond() -> [return: bb1, unwind: bb11]; // scope 1 at $DIR/issue_41888.rs:+2:8: +2:14
+                                           // mir::Constant
+                                           // + span: $DIR/issue_41888.rs:8:8: 8:12
+                                           // + literal: Const { ty: fn() -> bool {cond}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
+          switchInt(move _2) -> [0: bb7, otherwise: bb2]; // scope 1 at $DIR/issue_41888.rs:+2:8: +2:14
+      }
+  
+      bb2: {
+          StorageLive(_3);                 // scope 1 at $DIR/issue_41888.rs:+3:13: +3:20
+          StorageLive(_4);                 // scope 1 at $DIR/issue_41888.rs:+3:18: +3:19
+          _4 = K;                          // scope 1 at $DIR/issue_41888.rs:+3:18: +3:19
+          _3 = E::F(move _4);              // scope 1 at $DIR/issue_41888.rs:+3:13: +3:20
+          StorageDead(_4);                 // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
+-         replace(_1 <- move _3) -> [return: bb3, unwind: bb10]; // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         goto -> bb14;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
+      }
+  
+      bb3: {
+-         drop(_3) -> [return: bb4, unwind: bb11]; // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
++         goto -> bb4;                     // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
+      }
+  
+      bb4: {
+          StorageDead(_3);                 // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
+          _5 = discriminant(_1);           // scope 2 at $DIR/issue_41888.rs:+4:16: +4:24
+          switchInt(move _5) -> [0: bb5, otherwise: bb6]; // scope 2 at $DIR/issue_41888.rs:+4:16: +4:24
+      }
+  
+      bb5: {
+          StorageLive(_6);                 // scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
++         _9 = const false;                // scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
+          _6 = move ((_1 as F).0: K);      // scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
+          _0 = const ();                   // scope 2 at $DIR/issue_41888.rs:+4:29: +7:10
+          StorageDead(_6);                 // scope 1 at $DIR/issue_41888.rs:+7:9: +7:10
+          goto -> bb8;                     // scope 1 at $DIR/issue_41888.rs:+4:9: +7:10
+      }
+  
+      bb6: {
+          _0 = const ();                   // scope 1 at $DIR/issue_41888.rs:+7:10: +7:10
+          goto -> bb8;                     // scope 1 at $DIR/issue_41888.rs:+4:9: +7:10
+      }
+  
+      bb7: {
+          _0 = const ();                   // scope 1 at $DIR/issue_41888.rs:+8:6: +8:6
+          goto -> bb8;                     // scope 1 at $DIR/issue_41888.rs:+2:5: +8:6
+      }
+  
+      bb8: {
+          StorageDead(_2);                 // scope 1 at $DIR/issue_41888.rs:+8:5: +8:6
+-         drop(_1) -> bb9;                 // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         goto -> bb20;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
+      }
+  
+      bb9: {
++         _7 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         _8 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         _9 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
+          StorageDead(_1);                 // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
+          return;                          // scope 0 at $DIR/issue_41888.rs:+9:2: +9:2
+      }
+  
+      bb10 (cleanup): {
+          drop(_3) -> bb11;                // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
+      }
+  
+      bb11 (cleanup): {
+-         drop(_1) -> bb12;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         goto -> bb12;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
+      }
+  
+      bb12 (cleanup): {
+          resume;                          // scope 0 at $DIR/issue_41888.rs:+0:1: +9:2
++     }
++ 
++     bb13 (cleanup): {
++         _7 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         _8 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         _9 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         _1 = move _3;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         goto -> bb12;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++     }
++ 
++     bb14: {
++         _7 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         _8 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         _9 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         _1 = move _3;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         goto -> bb3;                     // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++     }
++ 
++     bb15: {
++         _7 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         goto -> bb9;                     // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     }
++ 
++     bb16 (cleanup): {
++         goto -> bb12;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     }
++ 
++     bb17: {
++         drop(_1) -> [return: bb15, unwind: bb12]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     }
++ 
++     bb18 (cleanup): {
++         drop(_1) -> bb12;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     }
++ 
++     bb19: {
++         _10 = discriminant(_1);          // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         switchInt(move _10) -> [0: bb15, otherwise: bb17]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     }
++ 
++     bb20: {
++         switchInt(_7) -> [0: bb15, otherwise: bb19]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     }
++ 
++     bb21 (cleanup): {
++         _11 = discriminant(_1);          // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         switchInt(move _11) -> [0: bb16, otherwise: bb18]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     }
++ 
++     bb22 (cleanup): {
++         switchInt(_7) -> [0: bb12, otherwise: bb21]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
+      }
+  }
+  
diff --git a/tests/mir-opt/issue_41888.rs b/tests/mir-opt/issue_41888.rs
index c1046c14dbf..0f10c0a1d09 100644
--- a/tests/mir-opt/issue_41888.rs
+++ b/tests/mir-opt/issue_41888.rs
@@ -2,7 +2,7 @@
 // check that we clear the "ADT master drop flag" even when there are
 // no fields to be dropped.
 
-// EMIT_MIR issue_41888.main.ElaborateDrops.after.mir
+// EMIT_MIR issue_41888.main.ElaborateDrops.diff
 fn main() {
     let e;
     if cond() {