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

[Thurston Dang via cfe-commits]

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@@ -795,12 +795,30 @@ static void addSanitizers(const Triple &TargetTriple,
     PB.registerOptimizerLastEPCallback(SanitizersCallback);
   }
 
-  if (LowerAllowCheckPass::IsRequested()) {
+  // SanitizeSkipHotCutoffs: doubles with range [0, 1]
+  // Opts.cutoffs: ints with range [0, 1000000]
+  std::optional<std::vector<int>> scaledCutoffs =
+      CodeGenOpts.SanitizeSkipHotCutoffs.getAllScaled(1000000);
+
+  // TODO: remove IsRequested()
+  if (LowerAllowCheckPass::IsRequested() || scaledCutoffs.has_value()) {
     // We want to call it after inline, which is about OptimizerEarlyEPCallback.
     PB.registerOptimizerEarlyEPCallback([&](ModulePassManager &MPM,
                                             OptimizationLevel Level,
                                             ThinOrFullLTOPhase Phase) {
       LowerAllowCheckPass::Options Opts;
+
+      // TODO: after removing IsRequested(), the if case will be unconditional
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thurstond wrote:

unsigned makes sense for Opts.cutoffs. But it seems unnecessarily restrictive to force SanitizerMaskCutoffs::getAllScaled to return unsigned.

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