| // Copyright (c) 2016 Google Inc. |
| // |
| // 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 LIBSPIRV_OPT_UNIFY_CONSTANT_PASS_H_ |
| #define LIBSPIRV_OPT_UNIFY_CONSTANT_PASS_H_ |
| |
| #include "module.h" |
| #include "pass.h" |
| |
| namespace spvtools { |
| namespace opt { |
| |
| // The optimization pass to de-duplicate the constants. Constants with exactly |
| // same values and identical form will be unified and only one constant will be |
| // kept for each unique pair of type and value. |
| // There are several cases not handled by this pass: |
| // 1) Constants defined by OpConstantNull instructions (null constants) and |
| // constants defined by OpConstantFalse, OpConstant or OpConstantComposite |
| // with value(s) 0 (zero-valued normal constants) are not considered |
| // equivalent. So null constants won't be used to replace zero-valued normal |
| // constants, and other constants won't replace the null constants either. |
| // 2) Whenever there are decorations to the constant's result id or its type |
| // id, the constants won't be handled, which means, it won't be used to |
| // replace any other constants, neither can other constants replace it. |
| // 3) NaN in float point format with different bit patterns are not unified. |
| class UnifyConstantPass : public Pass { |
| public: |
| const char* name() const override { return "unify-const"; } |
| bool Process(ir::Module*) override; |
| }; |
| |
| } // namespace opt |
| } // namespace spvtools |
| |
| #endif // LIBSPIRV_OPT_UNIFY_CONSTANT_PASS_H_ |