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// Copyright 2022 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef SRC_TINT_AST_TRANSFORM_DEMOTE_TO_HELPER_H_
#define SRC_TINT_AST_TRANSFORM_DEMOTE_TO_HELPER_H_
#include "src/tint/ast/transform/transform.h"
namespace tint::ast::transform {
/// Implement demote-to-helper semantics for discard statements.
///
/// For backend targets that implement discard by terminating the invocation, we need to change the
/// program to ensure that discarding the fragment does not affect uniformity with respect to
/// derivative operations. We do this by setting a global flag and masking all writes to storage
/// buffers and textures.
///
/// @note Depends on the following transforms to have been run first:
/// * PromoteSideEffectsToDecl
/// * ExpandCompoundAssignment
class DemoteToHelper final : public utils::Castable<DemoteToHelper, Transform> {
public:
/// Constructor
DemoteToHelper();
/// Destructor
~DemoteToHelper() override;
/// @copydoc Transform::Apply
ApplyResult Apply(const Program* program,
const DataMap& inputs,
DataMap& outputs) const override;
};
} // namespace tint::ast::transform
#endif // SRC_TINT_AST_TRANSFORM_DEMOTE_TO_HELPER_H_