[llvm] [LoopVectorize] Fix double-application of FindIV reduction expression in epilogue (PR #219362)

[Luke Lau via llvm-commits]

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@@ -879,18 +879,8 @@ static bool hasUnsupportedHeaderPhiRecipe(VPlan &Plan) {
               RecurrenceDescriptor::isFindLastRecurrenceKind(Kind) ||
               !RedPhi->getUnderlyingValue())
             return true;
-          // TODO: Add support for FindIV reductions with sunk expressions: the
-          // resume value from the main loop is in expression domain (e.g.,
-          // mul(ReducedIV, 3)), but the epilogue tracks raw IV values. A sunk
-          // expression is identified by a non-VPInstruction user of
-          // ComputeReductionResult.
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lukel97 wrote:

I think we still need to keep this TODO

https://github.com/llvm/llvm-project/pull/219362