[PATCH] D140751: Implement a FIXME for better poison handling in SimplifyCFG.

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

Test?



================
Comment at: llvm/lib/Transforms/Utils/SimplifyCFG.cpp:335
+      return true;
+    if (isa<UndefValue>(IV1) && isGuaranteedNotToBePoison(IV0))
+      return true;
----------------
You need to check PoisonValue first, because PoisonValue is also an UndefValue.


================
Comment at: llvm/lib/Transforms/Utils/SimplifyCFG.cpp:341
+      return true;
+    if (isa<PoisonValue>(IV1) && !isa<PoisonValue>(IV0))
+      return true;
----------------
The `!isa<PoisonValue>` checks shouldn't be necessary.


Repository:
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  https://reviews.llvm.org/D140751/new/

https://reviews.llvm.org/D140751