Rollup merge of #97597 - tmiasko:simplify-locals-side-effects, r=RalfJung,JakobDegen

Preserve unused pointer to address casts

Fixes #97421.

cc `@RalfJung`

2 files changed, 7 insertions, 3 deletions

diff --git a/compiler/rustc_mir_transform/src/dead_store_elimination.rs b/compiler/rustc_mir_transform/src/dead_store_elimination.rs
index 8becac34ed7..779f3c77815 100644
--- a/compiler/rustc_mir_transform/src/dead_store_elimination.rs
+++ b/compiler/rustc_mir_transform/src/dead_store_elimination.rs
@@ -34,7 +34,7 @@ pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, borrowed: &BitS
         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_pointer_int_cast() {
+                if !assign.1.is_safe_to_remove() {
                     continue;
                 }
             }
diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs
index 72e08343925..8a78ea5c82b 100644
--- a/compiler/rustc_mir_transform/src/simplify.rs
+++ b/compiler/rustc_mir_transform/src/simplify.rs
@@ -494,8 +494,12 @@ impl<'tcx> Visitor<'tcx> for UsedLocals {
             StatementKind::StorageLive(_local) | StatementKind::StorageDead(_local) => {}
 
             StatementKind::Assign(box (ref place, ref rvalue)) => {
-                self.visit_lhs(place, location);
-                self.visit_rvalue(rvalue, location);
+                if rvalue.is_safe_to_remove() {
+                    self.visit_lhs(place, location);
+                    self.visit_rvalue(rvalue, location);
+                } else {
+                    self.super_statement(statement, location);
+                }
             }
 
             StatementKind::SetDiscriminant { ref place, variant_index: _ }