[llvm] [VPlan] Move EVL-based transforms to VPlanEVLTransforms.cpp (NFC) (PR #209883)

[Ramkumar Ramachandra via llvm-commits]

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@@ -167,6 +167,29 @@ VPInstruction *findComputeReductionResult(VPReductionPHIRecipe *PhiR);
 /// Finds the incoming alias-mask within the vector preheader.
 VPValue *findIncomingAliasMask(const VPlan &Plan);
 
+/// Get any instruction opcode or intrinsic ID data embedded in recipe \p R.
+/// Returns an optional pair, where the first element indicates whether it is
+/// an intrinsic ID.
+std::optional<std::pair<bool, unsigned>>
+getOpcodeOrIntrinsicID(const VPSingleDefRecipe *R);
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artagnon wrote:

Would be good to keep this near vputils::getIntrinsicID, as in https://github.com/llvm/llvm-project/pull/208993?

https://github.com/llvm/llvm-project/pull/209883