[PATCH] D144319: [SimplifyCFG] Check if the return instruction causes undefined behavior

[Dávid Bolvanský via Phabricator via llvm-commits]

xbolva00 added a comment.

So maybe there is a real UB which is now exploited by stronger optimizations…



================
Comment at: llvm/lib/Transforms/Utils/SimplifyCFG.cpp:7135
+        return true;
+      // Return null to a nonnnull return value is undefined.
+      if (C->isNullValue() &&
----------------
if the result value is not used - is it?

check line 7172, it requires nonnnull+noundef for similar case.


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https://reviews.llvm.org/D144319