[llvm] [CodeExtractor] Terminate callsite blocks to new `noreturn` functions with `unreachable` (PR #84682)

[via llvm-commits]

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@@ -1895,16 +1911,6 @@ CodeExtractor::extractCodeRegion(const CodeExtractorAnalysisCache &CEAC,
 
   fixupDebugInfoPostExtraction(*oldFunction, *newFunction, *TheCall);
 
-  // Mark the new function `noreturn` if applicable. Terminators which resume
-  // exception propagation are treated as returning instructions. This is to
-  // avoid inserting traps after calls to outlined functions which unwind.
-  bool doesNotReturn = none_of(*newFunction, [](const BasicBlock &BB) {
-    const Instruction *Term = BB.getTerminator();
-    return isa<ReturnInst>(Term) || isa<ResumeInst>(Term);
-  });
-  if (doesNotReturn)
-    newFunction->setDoesNotReturn();
-
   LLVM_DEBUG(if (verifyFunction(*newFunction, &errs())) {
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goldsteinn wrote:

NB the comment around when `HotColdSplitting` is enabled:
```
  // Split out cold code. Splitting is done late to avoid hiding context from
  // other optimizations and inadvertently regressing performance. The tradeoff
  // is that this has a higher code size cost than splitting early.
```

https://github.com/llvm/llvm-project/pull/84682