[llvm] [SelectionDAG] Freeze dynamic vector indices lowered through the stack (PR #225031)

[Mahmoud Naderi via llvm-commits]

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@@ -25436,6 +25358,9 @@ SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) {
           if (!IsByteSized && Elmnt.getValueType().bitsLT(EltVT))
             Elmnt = DAG.getNode(ISD::ANY_EXTEND, DL, EltVT, Elmnt);
 
+          // Freeze the index, as clamping a poison index would be meaningless.
+          Index = DAG.getFreeze(Index);
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slant14 wrote:

yes, `freeze-vector.ll: freeze_dynamic_insertelement_chain_wide_vector`is intended for this

https://github.com/llvm/llvm-project/pull/225031