[llvm] [AA] Refine ModRefInfo taking into account `errnomem` location (PR #157495)

[Yingwei Zheng via llvm-commits]

================
@@ -997,6 +998,18 @@ ModRefInfo BasicAAResult::getModRefInfo(const CallBase *Call,
   }
 
   ModRefInfo Result = ArgMR | OtherMR;
+
+  // Refine writes to errno memory. We can safely exclude the errno location if
+  // the given memory location is an alloca, the size of the memory access is
+  // larger than the integer size, or if TBAA proves it does not alias errno.
+  if ((ErrnoMR | Result) != Result) {
+    if (ErrnoMR == ModRefInfo::Mod && !isa<AllocaInst>(Object) &&
----------------
dtcxzyw wrote:

```suggestion
    if (ErrnoMR == ModRefInfo::Mod && !isIdentifiedFunctionLocal(Object) &&
```

https://github.com/llvm/llvm-project/pull/157495