[llvm] [VPlan] Model FOR extract of exit value in VPlan. (PR #93395)

[via llvm-commits]

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@@ -137,6 +137,7 @@ bool VPRecipeBase::mayHaveSideEffects() const {
     case VPInstruction::Not:
     case VPInstruction::CalculateTripCountMinusVF:
     case VPInstruction::CanonicalIVIncrementForPart:
+    case VPInstruction::ExtractFromEnd:
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ayalz wrote:

Is this needed in this patch, given the LiveOut user, or only for the follow-up patch extracting the last element?
Worth a TODO? Temporarily to keep alive until VPUsers are introduced.

https://github.com/llvm/llvm-project/pull/93395