[llvm-branch-commits] [llvm] DAG: Avoid forming shufflevector from a single extract_vector_elt (PR #122672)

[Simon Pilgrim via llvm-branch-commits]

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@@ -23855,6 +23863,13 @@ SDValue DAGCombiner::reduceBuildVecToShuffle(SDNode *N) {
   // VecIn accordingly.
   bool DidSplitVec = false;
   if (VecIn.size() == 2) {
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RKSimon wrote:

Doesn't this just check for 2 vector sources, not that there is a single extraction index?

https://github.com/llvm/llvm-project/pull/122672