[clang] [llvm] [WebAssembly] Support acquire-release atomics in CodeGen (PR #184900)

[Matt Arsenault via cfe-commits]

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@@ -0,0 +1,97 @@
+//===-- WebAssemblyFixupAtomics.cpp - Fixup Atomics -----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief Fixes memory ordering operands for atomic instructions.
+///
+/// This is used because ISel selects atomics with a default value for the
+/// memory ordering immediate operand. Even though we run this pass early in
+/// the MI pass pipeline, MI passes should still use getMergedOrdering() on
+/// the MachineMemOperand to get the ordering rther than the immediate.
----------------
arsenm wrote:

```suggestion
/// the MachineMemOperand to get the ordering rather than the immediate.
```

https://github.com/llvm/llvm-project/pull/184900