RewriteMultielementSwizzleAssignment.h

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//

// Copyright 2025 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.

//

// RewriteMultielementSwizzleAssignment: WGSL does not support assignment to multielement swizzles.

// This splits them into mutliple assignments to single-element swizzles.

//

// For example:

//   vec3 v1 = ...;

//   vec3 v2 = ...;

//   v1.xy = v2.yz;

// is converted to:

//   vec3 v1 = ...;

//   vec3 v2 = ...;

//   vec2 sbbc = v2.yz;

//   v1.x = v2.x;

//   v1.y = v2.y;

//

// Note that temporaries are used in order to avoid duplicated side effects in the RHS.

//

// One special case is multiplication-by-a-matrix assignment:

//   vec.xy *= mat;

// is converted to something like

//   vec.x = (vec.xy * mat).x;

//   vec.y = (vec.xy * mat).y;

//

#ifndef COMPILER_TRANSLATOR_TREEOPS_WGSL_REWRITE_MULTIELEMENTSWIZZLEASSIGNMENT_H_

#define COMPILER_TRANSLATOR_TREEOPS_WGSL_REWRITE_MULTIELEMENTSWIZZLEASSIGNMENT_H_

#include "common/angleutils.h"

#include "compiler/translator/Compiler.h"

namespace sh

class TCompiler;

class TIntermBlock;

class TSymbolTable;

// Can only be called if CanRewriteMultiElementSwizzleAssignmentEasily() returns true for all

// multi-element swizzles assignments in the tree.

[[nodiscard]] bool RewriteMultielementSwizzleAssignment(TCompiler *compiler, TIntermBlock *root);

[[nodiscard]] bool IsMultielementSwizzleAssignment(TOperator op, TIntermTyped *assignedNode);

[[nodiscard]] bool CanRewriteMultiElementSwizzleAssignmentEasily(

    TIntermBinary *multielementSwizzleAssignment,

    TIntermNode *parent);

}  // namespace sh

#endif  // COMPILER_TRANSLATOR_TREEOPS_WGSL_REWRITE_MULTIELEMENTSWIZZLEASSIGNMENT_H_