[clang] [llvm] [AArch64] Implement the atomic store with hint intrinsic (PR #198316)

[Kerry McLaughlin via cfe-commits]

================
@@ -320,6 +321,94 @@ bool SemaARM::BuiltinARMSpecialReg(unsigned BuiltinID, CallExpr *TheCall,
   return false;
 }
 
+bool SemaARM::BuiltinARMAtomicStoreHintCall(unsigned BuiltinID,
+                                            CallExpr *TheCall) {
+  if (SemaRef.checkArgCount(TheCall, 4))
+    return true;
+
+  // Arg 0 should be the pointer type. The pointee type must be a
+  // scalar integral or floating-point type of 8, 16, 32 or 64 bits.
+  ASTContext &Context = getASTContext();
+  Expr *PtrArg = TheCall->getArg(0);
+  auto PtrArgRes = SemaRef.DefaultFunctionArrayLvalueConversion(PtrArg);
+  if (PtrArgRes.isInvalid())
+    return true;
+  auto *PtrTy = PtrArg->getType()->getAs<PointerType>();
+  if (!PtrTy)
+    return Diag(TheCall->getBeginLoc(),
+                diag::err_atomic_builtin_must_be_pointer)
+           << PtrArg->getType() << 0 << PtrArg->getSourceRange();
+  QualType PtrQT = PtrTy->getPointeeType();
+
+  // TODO: Allow MFloat8 types when supported by atomic store
+  if (!PtrQT->isIntegralType(getASTContext()) && !PtrQT->isFloatingType())
+    return Diag(TheCall->getBeginLoc(),
+                diag::err_atomic_op_needs_atomic_int_or_fp)
+           << 0 << PtrQT << PtrArg->getSourceRange();
+
+  unsigned TySize =
+      Context.getTypeSize(Context.getCanonicalType(PtrQT).getUnqualifiedType());
----------------
kmclaughlin-arm wrote:

Changed to:
```
unsigned TySize = Context.getTypeSize(PtrQT);
```

https://github.com/llvm/llvm-project/pull/198316