130 lines
5.3 KiB
C++
130 lines
5.3 KiB
C++
#include "Reg2Mem.h"
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#include <cstddef>
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#include <iostream>
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#include <list>
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#include <memory>
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namespace sysy {
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/**
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* 删除phi节点
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* 删除phi节点后可能会生成冗余存储代码
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*/
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void Reg2Mem::DeletePhiInst(){
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auto &functions = pModule->getFunctions();
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for (auto &function : functions) {
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auto basicBlocks = function.second->getBasicBlocks();
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for (auto &basicBlock : basicBlocks) {
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for (auto iter = basicBlock->begin(); iter != basicBlock->end();) {
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auto &instruction = *iter;
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if (instruction->isPhi()) {
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auto predBlocks = basicBlock->getPredecessors();
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// 寻找源和目的
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// 目的就是phi指令的第一个操作数
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// 源就是phi指令的后续操作数
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auto destination = instruction->getOperand(0);
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int predBlockindex = 0;
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for (auto &predBlock : predBlocks) {
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++predBlockindex;
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// 判断前驱块儿只有一个后继还是多个后继
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// 如果有多个
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auto source = instruction->getOperand(predBlockindex);
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if (source == destination) {
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continue;
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}
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// std::cout << predBlock->getNumSuccessors() << std::endl;
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if (predBlock->getNumSuccessors() > 1) {
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// 创建一个basicblock
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auto newbasicBlock = function.second->addBasicBlock();
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std::stringstream ss;
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ss << " phidel.L" << pBuilder->getLabelIndex();
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newbasicBlock->setName(ss.str());
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ss.str("");
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// // 修改前驱后继关系
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basicBlock->replacePredecessor(predBlock, newbasicBlock);
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// predBlock = newbasicBlock;
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newbasicBlock->addPredecessor(predBlock);
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newbasicBlock->addSuccessor(basicBlock.get());
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predBlock->removeSuccessor(basicBlock.get());
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predBlock->addSuccessor(newbasicBlock);
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// std::cout << "the block name is " << basicBlock->getName() << std::endl;
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// for (auto pb : basicBlock->getPredecessors()) {
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// // newbasicBlock->addPredecessor(pb);
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// std::cout << pb->getName() << std::endl;
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// }
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// sysy::BasicBlock::conectBlocks(newbasicBlock, static_cast<BasicBlock *>(basicBlock.get()));
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// 若后为跳转指令，应该修改跳转指令所到达的位置
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auto thelastinst = predBlock->end();
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(--thelastinst);
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if (thelastinst->get()->isConditional() || thelastinst->get()->isUnconditional()) { // 如果是跳转指令
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auto opnum = thelastinst->get()->getNumOperands();
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for (size_t i = 0; i < opnum; i++) {
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if (thelastinst->get()->getOperand(i) == basicBlock.get()) {
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thelastinst->get()->replaceOperand(i, newbasicBlock);
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}
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}
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}
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// 在新块中插入store指令
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pBuilder->setPosition(newbasicBlock, newbasicBlock->end());
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// pBuilder->createStoreInst(source, destination);
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if (source->isInt() || source->isFloat()) {
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pBuilder->createStoreInst(source, destination);
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} else {
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auto loadInst = pBuilder->createLoadInst(source);
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pBuilder->createStoreInst(loadInst, destination);
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}
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// pBuilder->createMoveInst(Instruction::kMove, destination->getType(), destination, source,
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// newbasicBlock);
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pBuilder->setPosition(newbasicBlock, newbasicBlock->end());
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pBuilder->createUncondBrInst(basicBlock.get(), {});
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} else {
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// 如果前驱块只有一个后继
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auto thelastinst = predBlock->end();
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(--thelastinst);
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// std::cout << predBlock->getName() << std::endl;
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// std::cout << thelastinst->get() << std::endl;
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// std::cout << "First point 11 " << std::endl;
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if (thelastinst->get()->isConditional() || thelastinst->get()->isUnconditional()) {
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// 在跳转语句前insert st指令
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pBuilder->setPosition(predBlock, thelastinst);
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} else {
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pBuilder->setPosition(predBlock, predBlock->end());
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}
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if (source->isInt() || source->isFloat()) {
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pBuilder->createStoreInst(source, destination);
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} else {
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auto loadInst = pBuilder->createLoadInst(source);
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pBuilder->createStoreInst(loadInst, destination);
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}
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}
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}
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// 删除phi指令
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auto &instructions = basicBlock->getInstructions();
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usedelete(iter->get());
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iter = instructions.erase(iter);
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if (basicBlock->getNumInstructions() == 0) {
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if (basicBlock->getNumSuccessors() == 1) {
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pBuilder->setPosition(basicBlock.get(), basicBlock->end());
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pBuilder->createUncondBrInst(basicBlock->getSuccessors()[0], {});
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}
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}
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} else {
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break;
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}
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}
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}
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}
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}
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void Reg2Mem::usedelete(Instruction *instr) {
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for (auto &use : instr->getOperands()) {
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auto val = use->getValue();
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val->removeUse(use);
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}
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}
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} // namespace sysy
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