[llvm] [VectorCombine] Prevent extract/ins rewrite to GEP (PR #150216)

[Simon Pilgrim via llvm-commits]

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@@ -3780,13 +3781,15 @@ bool VectorCombine::run() {
     // TODO: Identify and allow other scalable transforms
     if (IsVectorType) {
       MadeChange |= scalarizeOpOrCmp(I);
-      MadeChange |= scalarizeLoadExtract(I);
-      MadeChange |= scalarizeExtExtract(I);
+      if (!isSPIRV) {
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RKSimon wrote:

Avoid adding the logic here and add a TTI callback early-out inside scalarizeLoadExtract/scalarizeExtExtract/foldSingleElementStore directly.

https://github.com/llvm/llvm-project/pull/150216