[llvm] [LoopVectorize] In LoopVectorize.cpp start using getSymbolicMaxBackedgeTakenCount (PR #108833)

[David Sherwood via llvm-commits]

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@@ -9584,7 +9584,7 @@ static bool processLoopInVPlanNativePath(
     ProfileSummaryInfo *PSI, LoopVectorizeHints &Hints,
     LoopVectorizationRequirements &Requirements) {
 
-  if (isa<SCEVCouldNotCompute>(PSE.getBackedgeTakenCount())) {
+  if (isa<SCEVCouldNotCompute>(PSE.getSymbolicMaxBackedgeTakenCount())) {
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david-arm wrote:

You're absolutely right. I was being too eager! I looked and there is no defence against loops with uncountable exits, since LoopVectorizationLegality doesn't filter those out in advance. I've reverted this change.

https://github.com/llvm/llvm-project/pull/108833