[llvm] [InstCombine] Look through freeze to find insert instruction (PR #86948)

[Yingwei Zheng via llvm-commits]

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@@ -173,6 +173,12 @@ Value *llvm::findScalarElement(Value *V, unsigned EltNo) {
   if (Constant *C = dyn_cast<Constant>(V))
     return C->getAggregateElement(EltNo);
 
+  if (auto *F = dyn_cast<FreezeInst>(V)) {
+    if (isGuaranteedNotToBeUndefOrPoison(F)) {
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dtcxzyw wrote:

`isGuaranteedNotToBeUndefOrPoison` always evaluates to true :(

https://github.com/llvm/llvm-project/blob/a3efc53f168b1451803a40075201c3490d6e3928/llvm/lib/Analysis/ValueTracking.cpp#L7038-L7041

https://github.com/llvm/llvm-project/pull/86948