[clang] [CIR] Upstream __sync_<OP>_and_fetch builtins (PR #168347)

[Andy Kaylor via cfe-commits]

================
@@ -58,6 +59,107 @@ static RValue emitBuiltinBitOp(CIRGenFunction &cgf, const CallExpr *e,
   return RValue::get(result);
 }
 
+/// Emit the conversions required to turn the given value into an
+/// integer of the given size.
+static mlir::Value emitToInt(CIRGenFunction &cgf, mlir::Value v, QualType t,
+                             cir::IntType intType) {
+  v = cgf.emitToMemory(v, t);
+
+  if (isa<cir::PointerType>(v.getType()))
+    return cgf.getBuilder().createPtrToInt(v, intType);
+
+  assert(v.getType() == intType);
+  return v;
+}
+
+static mlir::Value emitFromInt(CIRGenFunction &cgf, mlir::Value v, QualType t,
+                               mlir::Type resultType) {
+  v = cgf.emitFromMemory(v, t);
+
+  if (isa<cir::PointerType>(resultType))
----------------
andykaylor wrote:

```suggestion
  if (mlir::isa<cir::PointerType>(resultType))
```

https://github.com/llvm/llvm-project/pull/168347