mirror of
https://github.com/KhronosGroup/SPIRV-Tools
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2e93e806e4
* Handles simple cases only * Identifies phis in blocks with two predecessors and attempts to convert the phi to an select * does not perform code motion currently so the converted values must dominate the join point (e.g. can't be defined in the branches) * limited for now to two predecessors, but can be extended to handle more cases * Adding if conversion to -O and -Os
42 lines
1.1 KiB
C++
42 lines
1.1 KiB
C++
// Copyright (c) 2018 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "dominator_analysis.h"
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#include <unordered_set>
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namespace spvtools {
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namespace opt {
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ir::BasicBlock* DominatorAnalysisBase::CommonDominator(
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ir::BasicBlock* b1, ir::BasicBlock* b2) const {
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if (!b1 || !b2) return nullptr;
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std::unordered_set<ir::BasicBlock*> seen;
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ir::BasicBlock* block = b1;
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while (block && seen.insert(block).second) {
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block = ImmediateDominator(block);
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}
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block = b2;
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while (block && !seen.count(block)) {
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block = ImmediateDominator(block);
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}
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return block;
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}
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} // namespace opt
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} // namespace spvtools
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