| // Copyright 2021 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_TRANSFORM_FOLD_TRIVIAL_SINGLE_USE_LETS_H_ |
| #define SRC_TINT_TRANSFORM_FOLD_TRIVIAL_SINGLE_USE_LETS_H_ |
| |
| #include <string> |
| #include <unordered_map> |
| |
| #include "src/tint/transform/transform.h" |
| |
| namespace tint::transform { |
| |
| /// FoldTrivialSingleUseLets is an optimizer for folding away trivial `let` |
| /// statements into their single place of use. This transform is intended to |
| /// clean up the SSA `let`s produced by the SPIR-V reader. |
| /// `let`s can only be folded if: |
| /// * There is a single usage of the `let` value. |
| /// * The `let` is constructed with a ScalarConstructorExpression, or with an |
| /// IdentifierExpression. |
| /// * There are only other foldable `let`s between the `let` declaration and its |
| /// single usage. |
| /// These rules prevent any hoisting of the let that may affect execution |
| /// behaviour. |
| class FoldTrivialSingleUseLets final |
| : public Castable<FoldTrivialSingleUseLets, Transform> { |
| public: |
| /// Constructor |
| FoldTrivialSingleUseLets(); |
| |
| /// Destructor |
| ~FoldTrivialSingleUseLets() override; |
| |
| protected: |
| /// Runs the transform using the CloneContext built for transforming a |
| /// program. Run() is responsible for calling Clone() on the CloneContext. |
| /// @param ctx the CloneContext primed with the input program and |
| /// ProgramBuilder |
| /// @param inputs optional extra transform-specific input data |
| /// @param outputs optional extra transform-specific output data |
| void Run(CloneContext& ctx, |
| const DataMap& inputs, |
| DataMap& outputs) const override; |
| }; |
| |
| } // namespace tint::transform |
| |
| #endif // SRC_TINT_TRANSFORM_FOLD_TRIVIAL_SINGLE_USE_LETS_H_ |