Perform JumpThreading in RPO order.

cjgillot · cjgillot · commit 976e3a3264e4 · 2025-06-21T10:32:53.000Z
diff --git a/compiler/rustc_mir_transform/src/jump_threading.rs b/compiler/rustc_mir_transform/src/jump_threading.rs
@@ -89,7 +89,7 @@ impl<'tcx> crate::MirPass<'tcx> for JumpThreading {
             opportunities: Vec::new(),
         };
 
-        for bb in body.basic_blocks.indices() {
+        for (bb, _) in traversal::reverse_postorder(body) {
             finder.start_from_switch(bb);
         }
 

Original file line number	Diff line number	Diff line change
`@@ -89,7 +89,7 @@ impl<'tcx> crate::MirPass<'tcx> for JumpThreading {`
`89`	`89`	`opportunities: Vec::new(),`
`90`	`90`	`};`
`91`	`91`
`92`		`- for bb in body.basic_blocks.indices() {`
	`92`	`+ for (bb, _) in traversal::reverse_postorder(body) {`
`93`	`93`	`finder.start_from_switch(bb);`
`94`	`94`	`}`
`95`	`95`