[llvm] [SLP] Fix crash on trying to reshuffle a scalar that was vectorized. (PR #72295)

[Alexey Bataev via llvm-commits]

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@@ -9164,7 +9164,8 @@ BoUpSLP::tryToGatherSingleRegisterExtractElements(
       continue;
     }
     auto *VecTy = dyn_cast<FixedVectorType>(EI->getVectorOperandType());
-    if (!VecTy || !isa<ConstantInt, UndefValue>(EI->getIndexOperand()))
+    if (!VecTy || !isa<ConstantInt, UndefValue>(EI->getIndexOperand()) ||
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alexey-bataev wrote:

I don't like this approach. Instead better to check if the vector operands depend on tree entires and delay the vectorization of this particular gather node. When "VectorizedValue" is ready, replace the vector operand with the vectorized value and perform shuffle.

https://github.com/llvm/llvm-project/pull/72295