[llvm] [LV][NFC] Refactor code for extracting first active element (PR #131118)

[David Sherwood via llvm-commits]

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@@ -461,6 +461,11 @@ Value *VPInstruction::generate(VPTransformState &State) {
     Value *A = State.get(getOperand(0));
     return Builder.CreateNot(A, Name);
   }
+  case Instruction::ExtractElement: {
+    Value *Vec = State.get(getOperand(0));
+    Value *Idx = State.get(getOperand(1), true);
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david-arm wrote:

I'm not sure how to handle that though because ExtractElement doesn't necessarily extract the first lane of operand 0. Or does `onlyFirstLaneUsed` refer to the result?

https://github.com/llvm/llvm-project/pull/131118