mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2025-01-07 07:20:05 +00:00
470 lines
15 KiB
C++
470 lines
15 KiB
C++
// Copyright (c) 2017 The Khronos Group Inc.
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// Copyright (c) 2017 Valve Corporation
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// Copyright (c) 2017 LunarG 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 "local_single_store_elim_pass.h"
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#include "cfa.h"
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#include "iterator.h"
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#include "spirv/1.0/GLSL.std.450.h"
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static const int kSpvEntryPointFunctionId = 1;
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static const int kSpvStorePtrId = 0;
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static const int kSpvStoreValId = 1;
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static const int kSpvLoadPtrId = 0;
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static const int kSpvAccessChainPtrId = 0;
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static const int kSpvTypePointerStorageClass = 0;
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static const int kSpvTypePointerTypeId = 1;
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// Universal Limit of ResultID + 1
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static const int kInvalidId = 0x400000;
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namespace spvtools {
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namespace opt {
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bool LocalSingleStoreElimPass::IsNonPtrAccessChain(const SpvOp opcode) const {
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return opcode == SpvOpAccessChain || opcode == SpvOpInBoundsAccessChain;
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}
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bool LocalSingleStoreElimPass::IsMathType(
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const ir::Instruction* typeInst) const {
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switch (typeInst->opcode()) {
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case SpvOpTypeInt:
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case SpvOpTypeFloat:
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case SpvOpTypeBool:
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case SpvOpTypeVector:
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case SpvOpTypeMatrix:
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return true;
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default:
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break;
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}
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return false;
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}
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bool LocalSingleStoreElimPass::IsTargetType(
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const ir::Instruction* typeInst) const {
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if (IsMathType(typeInst))
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return true;
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if (typeInst->opcode() == SpvOpTypeArray)
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return IsMathType(def_use_mgr_->GetDef(typeInst->GetSingleWordOperand(1)));
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if (typeInst->opcode() != SpvOpTypeStruct)
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return false;
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// All struct members must be math type
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int nonMathComp = 0;
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typeInst->ForEachInId([&nonMathComp,this](const uint32_t* tid) {
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ir::Instruction* compTypeInst = def_use_mgr_->GetDef(*tid);
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if (!IsMathType(compTypeInst)) ++nonMathComp;
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});
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return nonMathComp == 0;
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}
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ir::Instruction* LocalSingleStoreElimPass::GetPtr(
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ir::Instruction* ip, uint32_t* varId) {
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*varId = ip->GetSingleWordInOperand(
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ip->opcode() == SpvOpStore ? kSpvStorePtrId : kSpvLoadPtrId);
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ir::Instruction* ptrInst = def_use_mgr_->GetDef(*varId);
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ir::Instruction* varInst = ptrInst;
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while (IsNonPtrAccessChain(varInst->opcode())) {
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*varId = varInst->GetSingleWordInOperand(kSpvAccessChainPtrId);
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varInst = def_use_mgr_->GetDef(*varId);
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}
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return ptrInst;
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}
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bool LocalSingleStoreElimPass::IsTargetVar(uint32_t varId) {
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if (seen_non_target_vars_.find(varId) != seen_non_target_vars_.end())
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return false;
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if (seen_target_vars_.find(varId) != seen_target_vars_.end())
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return true;
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const ir::Instruction* varInst = def_use_mgr_->GetDef(varId);
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assert(varInst->opcode() == SpvOpVariable);
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const uint32_t varTypeId = varInst->type_id();
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const ir::Instruction* varTypeInst = def_use_mgr_->GetDef(varTypeId);
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if (varTypeInst->GetSingleWordInOperand(kSpvTypePointerStorageClass) !=
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SpvStorageClassFunction) {
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seen_non_target_vars_.insert(varId);
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return false;
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}
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const uint32_t varPteTypeId =
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varTypeInst->GetSingleWordInOperand(kSpvTypePointerTypeId);
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ir::Instruction* varPteTypeInst = def_use_mgr_->GetDef(varPteTypeId);
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if (!IsTargetType(varPteTypeInst)) {
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seen_non_target_vars_.insert(varId);
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return false;
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}
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seen_target_vars_.insert(varId);
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return true;
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}
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bool LocalSingleStoreElimPass::HasOnlySupportedRefs(uint32_t ptrId) {
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if (supported_ref_ptrs_.find(ptrId) != supported_ref_ptrs_.end())
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return true;
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analysis::UseList* uses = def_use_mgr_->GetUses(ptrId);
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assert(uses != nullptr);
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for (auto u : *uses) {
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SpvOp op = u.inst->opcode();
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if (IsNonPtrAccessChain(op)) {
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if (!HasOnlySupportedRefs(u.inst->result_id()))
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return false;
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}
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else if (op != SpvOpStore && op != SpvOpLoad && op != SpvOpName)
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return false;
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}
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supported_ref_ptrs_.insert(ptrId);
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return true;
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}
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void LocalSingleStoreElimPass::SingleStoreAnalyze(ir::Function* func) {
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ssa_var2store_.clear();
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non_ssa_vars_.clear();
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store2idx_.clear();
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store2blk_.clear();
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for (auto bi = func->begin(); bi != func->end(); ++bi) {
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uint32_t instIdx = 0;
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for (auto ii = bi->begin(); ii != bi->end(); ++ii, ++instIdx) {
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switch (ii->opcode()) {
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case SpvOpStore: {
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// Verify store variable is target type
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uint32_t varId;
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ir::Instruction* ptrInst = GetPtr(&*ii, &varId);
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if (non_ssa_vars_.find(varId) != non_ssa_vars_.end())
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continue;
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if (!HasOnlySupportedRefs(varId)) {
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non_ssa_vars_.insert(varId);
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continue;
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}
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if (IsNonPtrAccessChain(ptrInst->opcode())) {
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non_ssa_vars_.insert(varId);
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ssa_var2store_.erase(varId);
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continue;
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}
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// Verify target type and function storage class
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if (!IsTargetVar(varId)) {
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non_ssa_vars_.insert(varId);
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continue;
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}
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// Ignore variables with multiple stores
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if (ssa_var2store_.find(varId) != ssa_var2store_.end()) {
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non_ssa_vars_.insert(varId);
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ssa_var2store_.erase(varId);
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continue;
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}
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// Remember pointer to variable's store and it's
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// ordinal position in block
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ssa_var2store_[varId] = &*ii;
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store2idx_[&*ii] = instIdx;
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store2blk_[&*ii] = &*bi;
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} break;
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default:
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break;
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} // switch
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}
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}
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}
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void LocalSingleStoreElimPass::ReplaceAndDeleteLoad(
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ir::Instruction* loadInst, uint32_t replId) {
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(void) def_use_mgr_->ReplaceAllUsesWith(loadInst->result_id(), replId);
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DCEInst(loadInst);
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}
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LocalSingleStoreElimPass::GetBlocksFunction
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LocalSingleStoreElimPass::AugmentedCFGSuccessorsFunction() const {
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return [this](const ir::BasicBlock* block) {
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auto asmi = augmented_successors_map_.find(block);
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if (asmi != augmented_successors_map_.end())
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return &(*asmi).second;
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auto smi = successors_map_.find(block);
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return &(*smi).second;
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};
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}
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LocalSingleStoreElimPass::GetBlocksFunction
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LocalSingleStoreElimPass::AugmentedCFGPredecessorsFunction() const {
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return [this](const ir::BasicBlock* block) {
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auto apmi = augmented_predecessors_map_.find(block);
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if (apmi != augmented_predecessors_map_.end())
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return &(*apmi).second;
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auto pmi = predecessors_map_.find(block);
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return &(*pmi).second;
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};
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}
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void LocalSingleStoreElimPass::CalculateImmediateDominators(
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ir::Function* func) {
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// Compute CFG
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vector<ir::BasicBlock*> ordered_blocks;
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predecessors_map_.clear();
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successors_map_.clear();
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for (auto& blk : *func) {
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ordered_blocks.push_back(&blk);
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blk.ForEachSuccessorLabel([&blk, &ordered_blocks, this](uint32_t sbid) {
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successors_map_[&blk].push_back(label2block_[sbid]);
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predecessors_map_[label2block_[sbid]].push_back(&blk);
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});
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}
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// Compute Augmented CFG
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augmented_successors_map_.clear();
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augmented_predecessors_map_.clear();
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successors_map_[&pseudo_exit_block_] = {};
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predecessors_map_[&pseudo_entry_block_] = {};
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auto succ_func = [this](const ir::BasicBlock* b)
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{ return &successors_map_[b]; };
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auto pred_func = [this](const ir::BasicBlock* b)
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{ return &predecessors_map_[b]; };
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CFA<ir::BasicBlock>::ComputeAugmentedCFG(
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ordered_blocks,
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&pseudo_entry_block_,
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&pseudo_exit_block_,
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&augmented_successors_map_,
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&augmented_predecessors_map_,
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succ_func,
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pred_func);
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// Compute Dominators
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vector<const ir::BasicBlock*> postorder;
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auto ignore_block = [](cbb_ptr) {};
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auto ignore_edge = [](cbb_ptr, cbb_ptr) {};
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spvtools::CFA<ir::BasicBlock>::DepthFirstTraversal(
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ordered_blocks[0], AugmentedCFGSuccessorsFunction(),
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ignore_block, [&](cbb_ptr b) { postorder.push_back(b); },
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ignore_edge);
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auto edges = spvtools::CFA<ir::BasicBlock>::CalculateDominators(
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postorder, AugmentedCFGPredecessorsFunction());
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idom_.clear();
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for (auto edge : edges)
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idom_[edge.first] = edge.second;
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}
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bool LocalSingleStoreElimPass::Dominates(
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ir::BasicBlock* blk0, uint32_t idx0,
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ir::BasicBlock* blk1, uint32_t idx1) {
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if (blk0 == blk1)
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return idx0 <= idx1;
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ir::BasicBlock* b = blk1;
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while (idom_[b] != b) {
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b = idom_[b];
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if (b == blk0)
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return true;
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}
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return false;
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}
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bool LocalSingleStoreElimPass::SingleStoreProcess(ir::Function* func) {
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CalculateImmediateDominators(func);
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bool modified = false;
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for (auto bi = func->begin(); bi != func->end(); ++bi) {
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uint32_t instIdx = 0;
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for (auto ii = bi->begin(); ii != bi->end(); ++ii, ++instIdx) {
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if (ii->opcode() != SpvOpLoad)
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continue;
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uint32_t varId;
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ir::Instruction* ptrInst = GetPtr(&*ii, &varId);
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// Skip access chain loads
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if (IsNonPtrAccessChain(ptrInst->opcode()))
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continue;
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if (ptrInst->opcode() != SpvOpVariable)
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continue;
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const auto vsi = ssa_var2store_.find(varId);
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if (vsi == ssa_var2store_.end())
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continue;
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if (non_ssa_vars_.find(varId) != non_ssa_vars_.end())
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continue;
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// store must dominate load
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if (!Dominates(store2blk_[vsi->second], store2idx_[vsi->second], &*bi, instIdx))
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continue;
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// Use store value as replacement id
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uint32_t replId = vsi->second->GetSingleWordInOperand(kSpvStoreValId);
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// replace all instances of the load's id with the SSA value's id
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ReplaceAndDeleteLoad(&*ii, replId);
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modified = true;
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}
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}
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return modified;
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}
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bool LocalSingleStoreElimPass::HasLoads(uint32_t varId) const {
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analysis::UseList* uses = def_use_mgr_->GetUses(varId);
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if (uses == nullptr)
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return false;
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for (auto u : *uses) {
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SpvOp op = u.inst->opcode();
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// TODO(): The following is slightly conservative. Could be
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// better handling of non-store/name.
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if (IsNonPtrAccessChain(op) || op == SpvOpCopyObject) {
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if (HasLoads(u.inst->result_id()))
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return true;
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}
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else if (op != SpvOpStore && op != SpvOpName)
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return true;
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}
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return false;
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}
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bool LocalSingleStoreElimPass::IsLiveVar(uint32_t varId) const {
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// non-function scope vars are live
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const ir::Instruction* varInst = def_use_mgr_->GetDef(varId);
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assert(varInst->opcode() == SpvOpVariable);
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const uint32_t varTypeId = varInst->type_id();
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const ir::Instruction* varTypeInst = def_use_mgr_->GetDef(varTypeId);
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if (varTypeInst->GetSingleWordInOperand(kSpvTypePointerStorageClass) !=
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SpvStorageClassFunction)
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return true;
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// test if variable is loaded from
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return HasLoads(varId);
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}
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bool LocalSingleStoreElimPass::IsLiveStore(ir::Instruction* storeInst) {
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// get store's variable
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uint32_t varId;
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(void) GetPtr(storeInst, &varId);
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return IsLiveVar(varId);
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}
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void LocalSingleStoreElimPass::AddStores(
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uint32_t ptr_id, std::queue<ir::Instruction*>* insts) {
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analysis::UseList* uses = def_use_mgr_->GetUses(ptr_id);
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if (uses != nullptr) {
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for (auto u : *uses) {
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if (IsNonPtrAccessChain(u.inst->opcode()))
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AddStores(u.inst->result_id(), insts);
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else if (u.inst->opcode() == SpvOpStore)
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insts->push(u.inst);
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}
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}
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}
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void LocalSingleStoreElimPass::DCEInst(ir::Instruction* inst) {
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std::queue<ir::Instruction*> deadInsts;
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deadInsts.push(inst);
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while (!deadInsts.empty()) {
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ir::Instruction* di = deadInsts.front();
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// Don't delete labels
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if (di->opcode() == SpvOpLabel) {
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deadInsts.pop();
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continue;
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}
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// Remember operands
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std::queue<uint32_t> ids;
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di->ForEachInId([&ids](uint32_t* iid) {
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ids.push(*iid);
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});
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uint32_t varId = 0;
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// Remember variable if dead load
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if (di->opcode() == SpvOpLoad)
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(void) GetPtr(di, &varId);
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def_use_mgr_->KillInst(di);
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// For all operands with no remaining uses, add their instruction
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// to the dead instruction queue.
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while (!ids.empty()) {
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uint32_t id = ids.front();
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analysis::UseList* uses = def_use_mgr_->GetUses(id);
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if (uses == nullptr)
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deadInsts.push(def_use_mgr_->GetDef(id));
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ids.pop();
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}
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// if a load was deleted and it was the variable's
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// last load, add all its stores to dead queue
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if (varId != 0 && !IsLiveVar(varId))
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AddStores(varId, &deadInsts);
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deadInsts.pop();
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}
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}
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bool LocalSingleStoreElimPass::SingleStoreDCE() {
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bool modified = false;
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for (auto v : ssa_var2store_) {
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// check that it hasn't already been DCE'd
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if (v.second->opcode() != SpvOpStore)
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continue;
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if (non_ssa_vars_.find(v.first) != non_ssa_vars_.end())
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continue;
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if (!IsLiveStore(v.second)) {
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DCEInst(v.second);
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modified = true;
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}
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}
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return modified;
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}
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bool LocalSingleStoreElimPass::LocalSingleStoreElim(ir::Function* func) {
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bool modified = false;
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SingleStoreAnalyze(func);
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if (ssa_var2store_.empty())
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return false;
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modified |= SingleStoreProcess(func);
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modified |= SingleStoreDCE();
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return modified;
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}
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void LocalSingleStoreElimPass::Initialize(ir::Module* module) {
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module_ = module;
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// Initialize function and block maps
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id2function_.clear();
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label2block_.clear();
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for (auto& fn : *module_) {
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id2function_[fn.result_id()] = &fn;
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for (auto& blk : fn) {
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uint32_t bid = blk.id();
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label2block_[bid] = &blk;
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}
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}
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// Initialize Target Type Caches
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seen_target_vars_.clear();
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seen_non_target_vars_.clear();
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// Initialize Supported Ref Pointer Cache
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supported_ref_ptrs_.clear();
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// TODO: Reuse def/use (and other state) from previous passes
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def_use_mgr_.reset(new analysis::DefUseManager(consumer(), module_));
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// Initialize next unused Id
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next_id_ = module_->id_bound();
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};
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Pass::Status LocalSingleStoreElimPass::ProcessImpl() {
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// Assumes logical addressing only
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if (module_->HasCapability(SpvCapabilityAddresses))
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return Status::SuccessWithoutChange;
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bool modified = false;
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// Call Mem2Reg on all remaining functions.
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for (auto& e : module_->entry_points()) {
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ir::Function* fn =
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id2function_[e.GetSingleWordOperand(kSpvEntryPointFunctionId)];
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modified = LocalSingleStoreElim(fn) || modified;
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}
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FinalizeNextId(module_);
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return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
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}
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LocalSingleStoreElimPass::LocalSingleStoreElimPass()
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: module_(nullptr), def_use_mgr_(nullptr),
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pseudo_entry_block_(std::unique_ptr<ir::Instruction>(
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new ir::Instruction(SpvOpLabel, 0, 0, {}))),
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pseudo_exit_block_(std::unique_ptr<ir::Instruction>(
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new ir::Instruction(SpvOpLabel, 0, kInvalidId, {}))),
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next_id_(0) {}
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Pass::Status LocalSingleStoreElimPass::Process(ir::Module* module) {
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Initialize(module);
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return ProcessImpl();
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}
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} // namespace opt
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} // namespace spvtools
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