[llvm] [InstCombine] Treat identical operands as one in pushFreezeToPreventPoisonFromPropagating (PR #145348)

[Nikita Popov via llvm-commits]

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@@ -4774,7 +4774,9 @@ InstCombinerImpl::pushFreezeToPreventPoisonFromPropagating(FreezeInst &OrigFI) {
   Use *MaybePoisonOperand = nullptr;
   for (Use &U : OrigOpInst->operands()) {
     if (isa<MetadataAsValue>(U.get()) ||
-        isGuaranteedNotToBeUndefOrPoison(U.get()))
+        isGuaranteedNotToBeUndefOrPoison(U.get()) ||
+        // Treat identical operands as a single operand.
+        (MaybePoisonOperand && MaybePoisonOperand->get() == U.get()))
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nikic wrote:

You should probably switch this code from working on Use* to working on Value*.

https://github.com/llvm/llvm-project/pull/145348