SPIRV-Tools/source/opt/loop_unswitch_pass.h
Victor Lomuller 3497a94460 Add loop unswitch pass.
It moves all conditional branching and switch whose conditions are loop
invariant and uniform. Before performing the loop unswitch we check that
the loop does not contain any instruction that would prevent it
(barriers, group instructions etc.).
2018-02-27 08:52:46 -05:00

44 lines
1.5 KiB
C++

// Copyright (c) 2018 Google LLC.
//
// 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_LOOP_UNSWITCH_PASS_H_
#define LIBSPIRV_OPT_LOOP_UNSWITCH_PASS_H_
#include "opt/loop_descriptor.h"
#include "opt/pass.h"
namespace spvtools {
namespace opt {
// Implements the loop unswitch optimization.
// The loop unswitch hoists invariant "if" statements if the conditions are
// constant within the loop and clones the loop for each branch.
class LoopUnswitchPass : public Pass {
public:
const char* name() const override { return "loop-unswitch"; }
// Processes the given |module|. Returns Status::Failure if errors occur when
// processing. Returns the corresponding Status::Success if processing is
// succesful to indicate whether changes have been made to the modue.
Pass::Status Process(ir::IRContext* context) override;
private:
bool ProcessFunction(ir::Function* f);
};
} // namespace opt
} // namespace spvtools
#endif // !LIBSPIRV_OPT_LOOP_UNSWITCH_PASS_H_