SPIRV-Tools/source/opt/block_merge_pass.h
Steven Perron a1f9e1342e Preserve inst-to-block and def-use in passes.
The following passes are updated to preserve the inst-to-block and
def-use analysies:

	private-to-local
	aggressive dead-code elimination
	dead branch elimination
	local-single-block elimination
	local-single-store elimination
	reduce load size
	compact ids (inst-to-block only)
	merge block
	dead-insert elimination
	ccp

The one execption is that compact ids still kills the def-use manager.
This is because it changes so many ids it is faster to kill and rebuild.

Does everything in
https://github.com/KhronosGroup/SPIRV-Tools/issues/1593 except for the
changes to merge return.
2018-06-04 13:48:30 -04:00

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2.3 KiB
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// Copyright (c) 2017 The Khronos Group Inc.
// Copyright (c) 2017 Valve Corporation
// Copyright (c) 2017 LunarG 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_BLOCK_MERGE_PASS_H_
#define LIBSPIRV_OPT_BLOCK_MERGE_PASS_H_
#include <algorithm>
#include <map>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include "basic_block.h"
#include "def_use_manager.h"
#include "ir_context.h"
#include "module.h"
#include "pass.h"
namespace spvtools {
namespace opt {
// See optimizer.hpp for documentation.
class BlockMergePass : public Pass {
public:
BlockMergePass();
const char* name() const override { return "merge-blocks"; }
Status Process(ir::IRContext*) override;
virtual ir::IRContext::Analysis GetPreservedAnalyses() override {
return ir::IRContext::kAnalysisDefUse |
ir::IRContext::kAnalysisInstrToBlockMapping |
ir::IRContext::kAnalysisDecorations |
ir::IRContext::kAnalysisCombinators |
ir::IRContext::kAnalysisNameMap;
}
private:
// Kill any OpName instruction referencing |inst|, then kill |inst|.
void KillInstAndName(ir::Instruction* inst);
// Search |func| for blocks which have a single Branch to a block
// with no other predecessors. Merge these blocks into a single block.
bool MergeBlocks(ir::Function* func);
// Returns true if |block| (or |id|) contains a merge instruction.
bool IsHeader(ir::BasicBlock* block);
bool IsHeader(uint32_t id);
// Returns true if |block| (or |id|) is the merge target of a merge
// instruction.
bool IsMerge(ir::BasicBlock* block);
bool IsMerge(uint32_t id);
void Initialize(ir::IRContext* c);
Pass::Status ProcessImpl();
};
} // namespace opt
} // namespace spvtools
#endif // LIBSPIRV_OPT_BLOCK_MERGE_PASS_H_