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https://github.com/KhronosGroup/SPIRV-Tools
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c20a718e00
The local-single-store-elim algorithm is not fundamentally bad. However, when there are a large number of variables, some of the maps that are used can become very large. These large data structures then take a very long time to be destroyed. I've seen cases around 40% if the time. I've rewritten that algorithm to not use as much memory. This give a significant improvement when running a large number of shader through DXC. I've also made a small change to local-single-block-elim to delete the loads that is has replaced. That way local-single-store-elim will not have to look at those. local-single-store-elim now does the same thing. The time for one set goes from 309s down to 126s. For another set, the time goes from 102s down to 88s.
70 lines
1.7 KiB
C++
70 lines
1.7 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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#include "ir_context.h"
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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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bool DominatorAnalysisBase::Dominates(ir::Instruction* a,
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ir::Instruction* b) const {
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if (!a || !b) {
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return false;
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}
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if (a == b) {
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return true;
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}
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ir::BasicBlock* bb_a = a->context()->get_instr_block(a);
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ir::BasicBlock* bb_b = b->context()->get_instr_block(b);
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if (bb_a != bb_b) {
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return tree_.Dominates(bb_a, bb_b);
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}
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ir::Instruction* current_inst = a;
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while ((current_inst = current_inst->NextNode())) {
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if (current_inst == b) {
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return true;
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}
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}
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return false;
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}
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} // namespace opt
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} // namespace spvtools
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