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https://github.com/KhronosGroup/SPIRV-Tools
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d42f65e7c1
The unordered_set in ADCE that holds all of the live instructions takes a very long time to be destroyed. In some shaders, it takes over 40% of the time. If we look at the unique ids of the live instructions, I believe they are dense enough make a simple bit vector a good choice for to hold that data. When I check the density of the bit vector for larger shaders, we are usually using less than 4 bytes per element in the vector, and almost always less than 16. So, in this commit, I introduce a simple bit vector class, and use it in ADCE. This help improve the compile time for some shaders on windows by the 40% mentioned above. Contributes to https://github.com/KhronosGroup/SPIRV-Tools/issues/1328.
41 lines
1.1 KiB
C++
41 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 "bit_vector.h"
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#include <iostream>
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namespace spvtools {
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namespace utils {
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void BitVector::ReportDensity(std::ostream& out) {
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uint32_t count = 0;
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for (BitContainer e : bits_) {
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while (e != 0) {
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if ((e & 1) != 0) {
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++count;
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}
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e = e >> 1;
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}
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}
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out << "count=" << count
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<< ", total size (bytes)=" << bits_.size() * sizeof(BitContainer)
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<< ", bytes per element="
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<< (double)(bits_.size() * sizeof(BitContainer)) / (double)(count);
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}
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} // namespace utils
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} // namespace spvtools
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