[clang] [ubsan] Connect -fsanitize-skip-hot-cutoff to LowerAllowCheckPass<cutoffs> (PR #124857)

[Thurston Dang via cfe-commits]

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@@ -795,12 +795,29 @@ static void addSanitizers(const Triple &TargetTriple,
     PB.registerOptimizerLastEPCallback(SanitizersCallback);
   }
 
-  if (LowerAllowCheckPass::IsRequested()) {
+  bool lowerAllowCheck = LowerAllowCheckPass::IsRequested();
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thurstond wrote:

Even after removing the epsilon check, isn't it still more efficient to have check if any of the cutoffs are non-zero?

If all the cutoffs are zero, CodeGen would not have inserted any llvm.allow.ubsan.check, hence we don't need to call the lowering pass.


https://github.com/llvm/llvm-project/pull/124857