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63 lines
2.0 KiB
C++
63 lines
2.0 KiB
C++
// Copyright (c) 2017 Google Inc.
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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 "source/opt/redundancy_elimination.h"
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#include "source/opt/value_number_table.h"
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namespace spvtools {
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namespace opt {
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Pass::Status RedundancyEliminationPass::Process() {
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bool modified = false;
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ValueNumberTable vnTable(context());
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for (auto& func : *get_module()) {
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if (func.IsDeclaration()) {
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continue;
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}
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// Build the dominator tree for this function. It is how the code is
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// traversed.
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DominatorTree& dom_tree =
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context()->GetDominatorAnalysis(&func)->GetDomTree();
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if (EliminateRedundanciesFrom(dom_tree.GetRoot(), vnTable)) {
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modified = true;
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}
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}
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return (modified ? Status::SuccessWithChange : Status::SuccessWithoutChange);
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}
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bool RedundancyEliminationPass::EliminateRedundanciesFrom(
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DominatorTreeNode* bb, const ValueNumberTable& vnTable) {
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struct State {
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DominatorTreeNode* node;
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std::map<uint32_t, uint32_t> value_to_id_map;
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};
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std::vector<State> todo;
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todo.push_back({bb, std::map<uint32_t, uint32_t>()});
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bool modified = false;
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for (size_t next_node = 0; next_node < todo.size(); next_node++) {
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modified |= EliminateRedundanciesInBB(todo[next_node].node->bb_, vnTable,
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&todo[next_node].value_to_id_map);
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for (DominatorTreeNode* child : todo[next_node].node->children_) {
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todo.push_back({child, todo[next_node].value_to_id_map});
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}
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}
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return modified;
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}
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} // namespace opt
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} // namespace spvtools
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