[llvm] [DSE] Handle provenance when eliminating tautological assignments (PR #184311)

[Antonio Frighetto via llvm-commits]

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@@ -2275,6 +2276,12 @@ bool DSEState::dominatingConditionImpliesValue(MemoryDef *Def) {
       !ICmpInst::isEquality(Pred))
     return false;
 
+  // Ensure the replacement is allowed when comparing pointers, as
+  // the equality compares addresses only, not pointers' provenance.
+  if (StoreVal->getType()->isPointerTy() &&
+      !canReplacePointersIfEqual(ICmpL, StoreVal, DL))
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antoniofrighetto wrote:

Right, thanks, was a bit perplexed that we should have introduced the ConstantPointerNull carveout here in DSE. Addressed separately.

https://github.com/llvm/llvm-project/pull/184311