simplifycfg: Mark as changed when start is modified in collapse goto chain

dianqk · dianqk · commit 2909de557c6f · 2025-08-06T20:26:10.000+08:00
diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs
@@ -225,6 +225,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
             current = target;
         }
         let last = current;
+        *changed |= *start != last;
         *start = last;
         while let Some((current, mut terminator)) = terminators.pop() {
             let Terminator { kind: TerminatorKind::Goto { ref mut target }, .. } = terminator

Original file line number	Diff line number	Diff line change
`@@ -225,6 +225,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {`
`225`	`225`	`current = target;`
`226`	`226`	`}`
`227`	`227`	`let last = current;`
	`228`	`+ changed \|= start != last;`
`228`	`229`	`*start = last;`
`229`	`230`	`while let Some((current, mut terminator)) = terminators.pop() {`
`230`	`231`	`let Terminator { kind: TerminatorKind::Goto { ref mut target }, .. } = terminator`