mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-11-30 15:00:06 +00:00
126 lines
3.7 KiB
C++
126 lines
3.7 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 "opt/licm_pass.h"
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#include "opt/module.h"
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#include "opt/pass.h"
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#include <queue>
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#include <utility>
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namespace spvtools {
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namespace opt {
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Pass::Status LICMPass::Process(ir::IRContext* c) {
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InitializeProcessing(c);
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bool modified = false;
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if (c != nullptr) {
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modified = ProcessIRContext();
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}
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return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
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}
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bool LICMPass::ProcessIRContext() {
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bool modified = false;
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ir::Module* module = get_module();
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// Process each function in the module
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for (ir::Function& f : *module) {
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modified |= ProcessFunction(&f);
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}
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return modified;
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}
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bool LICMPass::ProcessFunction(ir::Function* f) {
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bool modified = false;
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ir::LoopDescriptor* loop_descriptor = context()->GetLoopDescriptor(f);
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// Process each loop in the function
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for (ir::Loop& loop : *loop_descriptor) {
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// Ignore nested loops, as we will process them in order in ProcessLoop
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if (loop.IsNested()) {
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continue;
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}
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modified |= ProcessLoop(&loop, f);
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}
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return modified;
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}
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bool LICMPass::ProcessLoop(ir::Loop* loop, ir::Function* f) {
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bool modified = false;
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// Process all nested loops first
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for (ir::Loop* nested_loop : *loop) {
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modified |= ProcessLoop(nested_loop, f);
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}
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std::vector<ir::BasicBlock*> loop_bbs{};
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modified |= AnalyseAndHoistFromBB(loop, f, loop->GetHeaderBlock(), &loop_bbs);
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for (size_t i = 0; i < loop_bbs.size(); ++i) {
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ir::BasicBlock* bb = loop_bbs[i];
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// do not delete the element
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modified |= AnalyseAndHoistFromBB(loop, f, bb, &loop_bbs);
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}
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return modified;
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}
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bool LICMPass::AnalyseAndHoistFromBB(ir::Loop* loop, ir::Function* f,
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ir::BasicBlock* bb,
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std::vector<ir::BasicBlock*>* loop_bbs) {
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bool modified = false;
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std::function<void(ir::Instruction*)> hoist_inst =
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[this, &loop, &modified](ir::Instruction* inst) {
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if (loop->ShouldHoistInstruction(this->context(), inst)) {
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HoistInstruction(loop, inst);
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modified = true;
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}
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};
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if (IsImmediatelyContainedInLoop(loop, f, bb)) {
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bb->ForEachInst(hoist_inst, false);
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}
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opt::DominatorAnalysis* dom_analysis =
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context()->GetDominatorAnalysis(f, *cfg());
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opt::DominatorTree& dom_tree = dom_analysis->GetDomTree();
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for (opt::DominatorTreeNode* child_dom_tree_node :
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*dom_tree.GetTreeNode(bb)) {
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if (loop->IsInsideLoop(child_dom_tree_node->bb_)) {
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loop_bbs->push_back(child_dom_tree_node->bb_);
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}
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}
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return modified;
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}
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bool LICMPass::IsImmediatelyContainedInLoop(ir::Loop* loop, ir::Function* f,
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ir::BasicBlock* bb) {
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ir::LoopDescriptor* loop_descriptor = context()->GetLoopDescriptor(f);
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return loop == (*loop_descriptor)[bb->id()];
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}
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void LICMPass::HoistInstruction(ir::Loop* loop, ir::Instruction* inst) {
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ir::BasicBlock* pre_header_bb = loop->GetOrCreatePreHeaderBlock();
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inst->InsertBefore(std::move(&(*pre_header_bb->tail())));
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context()->set_instr_block(inst, pre_header_bb);
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}
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} // namespace opt
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} // namespace spvtools
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