[PATCH] D65451: [DivRemPairs] Avoid RAUW pitfalls (PR42823)

[Sanjay Patel via Phabricator via llvm-commits]

spatel accepted this revision.
spatel added a comment.
This revision is now accepted and ready to land.

LGTM - should the test from https://bugs.llvm.org/show_bug.cgi?id=42823 be included with this patch even if does not fail yet without D65298 <https://reviews.llvm.org/D65298>?



================
Comment at: llvm/lib/Transforms/Scalar/DivRemPairs.cpp:210-214
       // Now kill the explicit remainder. We have replaced it with:
       // (sub X, (mul (div X, Y), Y)
-      RemInst->replaceAllUsesWith(Sub);
-      RemInst->eraseFromParent();
+      Sub->setName(RemInst->getName() + ".decomposed");
+      Instruction *OrigRemInst = RemInst;
+      RemInst = Sub;
----------------
Add to this code comment to explain why we need to preserve the Sub in RemInst?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D65451/new/

https://reviews.llvm.org/D65451