[llvm] [LoopVectorize] Enable vectorisation of early exit loops with live-outs (PR #120567)

[David Sherwood via llvm-commits]

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@@ -697,14 +697,21 @@ Value *VPInstruction::generate(VPTransformState &State) {
     Value *A = State.get(getOperand(0));
     return Builder.CreateOrReduce(A);
   }
-
+  case VPInstruction::ExtractFirstActive: {
+    Value *Vec = State.get(getOperand(0));
+    Value *Mask = State.get(getOperand(1));
+    Value *Ctz =
+        Builder.CreateCountTrailingZeroElems(Builder.getInt64Ty(), Mask);
+    return Builder.CreateExtractElement(Vec, Ctz);
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david-arm wrote:

Yep, good suggestion!

https://github.com/llvm/llvm-project/pull/120567