[llvm] [LV] Update LoopVectorizationPlanner::emitInvalidCostRemarks to handle reduction plans (PR #165913)

[Florian Hahn via llvm-commits]

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@@ -0,0 +1,25 @@
+; RUN: opt < %s -passes=loop-vectorize -S -pass-remarks=loop-vectorize -debug-only=loop-vectorize &> %t
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fhahn wrote:

if the test is not checking the LLVM IR output, you can add `-disable-output`. Also, it is only checking the remarks, right? So `-debug-only=...` can also be dropped

https://github.com/llvm/llvm-project/pull/165913