[llvm] [LoopVectorize] Compute BlockFrequencyInfo eagerly to fix assertion failure (PR #215237)

[Karthika Devi C via llvm-commits]

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@@ -8478,9 +8478,13 @@ PreservedAnalyses LoopVectorizePass::run(Function &F,
 
   auto &MAMProxy = AM.getResult<ModuleAnalysisManagerFunctionProxy>(F);
   PSI = MAMProxy.getCachedResult<ProfileSummaryAnalysis>(*F.getParent());
-  GetBFI = [&AM, &F]() -> BlockFrequencyInfo & {
-    return AM.getResult<BlockFrequencyAnalysis>(F);
-  };
+  // Compute BFI eagerly rather than lazily. LoopVectorize may modify the
+  // function (vectorizing earlier loops) before requesting BFI for later loops.
+  // If BFI is computed lazily after such modifications, its dependency
+  // CycleAnalysis may be stale (holding pointers to deleted blocks), causing
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kartcq wrote:

I have tried this approach in latest patchset 
Please let me know your thoughts on the patch
Pushed the same to my other perf branch for compile time tracking as well.

CC - @fhahn @aengelke 

https://github.com/llvm/llvm-project/pull/215237