[llvm] [VPlan] Extract reverse operation for reverse accesses (PR #146525)

[Mel Chen via llvm-commits]

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@@ -917,6 +918,8 @@ Value *VPInstruction::generate(VPTransformState &State) {
 
     return Res;
   }
+  case VPInstruction::Reverse:
+    return Builder.CreateVectorReverse(State.get(getOperand(0)), "reverse");
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Mel-Chen wrote:

@fhahn What do you think? I’d like to hear your suggestion. If you feel that changing it to `res = reverse op, N` isn’t appropriate, that’s fine. We can still convert VPInstruction::Reverse into VPWidenIntrinsicRecipe along the def-use/use-def chain from VPWidenLoad/StoreEVLRecipe.

https://github.com/llvm/llvm-project/pull/146525