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diff --git a/gfx/angle/checkout/src/compiler/translator/tree_ops/d3d/RewriteAtomicFunctionExpressions.h b/gfx/angle/checkout/src/compiler/translator/tree_ops/d3d/RewriteAtomicFunctionExpressions.h
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+//
+// Copyright 2018 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// RewriteAtomicFunctionExpressions rewrites the expressions that contain
+// atomic function calls and cannot be directly translated into HLSL into
+// several simple ones that can be easily handled in the HLSL translator.
+//
+// We need to rewite these expressions because:
+// 1. All GLSL atomic functions have return values, which all represent the
+//    original value of the shared or ssbo variable; while all HLSL atomic
+//    functions don't, and the original value can be stored in the last
+//    parameter of the function call.
+// 2. For HLSL atomic functions, the last parameter that stores the original
+//    value is optional except for InterlockedExchange and
+//    InterlockedCompareExchange. Missing original_value in the call of
+//    InterlockedExchange or InterlockedCompareExchange results in a compile
+//    error from HLSL compiler.
+//
+// RewriteAtomicFunctionExpressions is a function that can modify the AST
+// to ensure all the expressions that contain atomic function calls can be
+// directly translated into HLSL expressions.
+
+#ifndef COMPILER_TRANSLATOR_TREEOPS_D3D_REWRITE_ATOMIC_FUNCTION_EXPRESSIONS_H_
+#define COMPILER_TRANSLATOR_TREEOPS_D3D_REWRITE_ATOMIC_FUNCTION_EXPRESSIONS_H_
+
+#include "common/angleutils.h"
+
+namespace sh
+{
+class TCompiler;
+class TIntermNode;
+class TSymbolTable;
+
+[[nodiscard]] bool RewriteAtomicFunctionExpressions(TCompiler *compiler,
+                                                    TIntermNode *root,
+                                                    TSymbolTable *symbolTable,
+                                                    int shaderVersion);
+}  // namespace sh
+
+#endif  // COMPILER_TRANSLATOR_TREEOPS_D3D_REWRITE_ATOMIC_FUNCTION_EXPRESSIONS_H_