[PATCH] D48040: Implement constexpr __builtin_*_overflow

[Eli Friedman via Phabricator via cfe-commits]

efriedma added inline comments.


================
Comment at: lib/Sema/SemaChecking.cpp:210
+    Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
+    TheCall->setArg(I, Arg.get());
   }
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Can you split this change into a separate patch?  Testcase:

```
int a() {
  const int x = 3;
  static int z;
  constexpr int * y = &z;
  return []() { return __builtin_sub_overflow(x,x,y); }();
}```


https://reviews.llvm.org/D48040