[clang] [clang][CodeGen] `sret` args should always point to the `alloca` AS, so use that (PR #114062)

[Matt Arsenault via cfe-commits]

================
@@ -5158,14 +5155,17 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
     } else if (!ReturnValue.isNull()) {
       SRetPtr = ReturnValue.getAddress();
     } else {
-      SRetPtr = CreateMemTemp(RetTy, "tmp", &SRetAlloca);
+      SRetPtr = CreateMemTempWithoutCast(RetTy, "tmp");
       if (HaveInsertPoint() && ReturnValue.isUnused()) {
         llvm::TypeSize size =
             CGM.getDataLayout().getTypeAllocSize(ConvertTypeForMem(RetTy));
-        UnusedReturnSizePtr = EmitLifetimeStart(size, SRetAlloca.getPointer());
+        UnusedReturnSizePtr = EmitLifetimeStart(size, SRetPtr.getBasePointer());
       }
     }
     if (IRFunctionArgs.hasSRetArg()) {
+      // If the caller allocated the return slot, it is possible that the
----------------
arsenm wrote:

Comment false now that this uses CreateMemTempWithoutCast?

https://github.com/llvm/llvm-project/pull/114062