forked from OSchip/llvm-project
85 lines
2.9 KiB
C++
85 lines
2.9 KiB
C++
//===--- Utils.cpp - Utility functions for the code generation --*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains utility functions for the code generation.
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//
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//===----------------------------------------------------------------------===//
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#include "polly/CodeGen/Utils.h"
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#include "polly/ScopInfo.h"
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#include "llvm/IRBuilder.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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using namespace llvm;
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BasicBlock *polly::executeScopConditionally(Scop &S, Pass *PassInfo) {
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BasicBlock *StartBlock, *SplitBlock, *NewBlock;
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Region &R = S.getRegion();
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IRBuilder<> Builder(R.getEntry());
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DominatorTree &DT = PassInfo->getAnalysis<DominatorTree>();
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RegionInfo &RI = PassInfo->getAnalysis<RegionInfo>();
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// Split the entry edge of the region and generate a new basic block on this
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// edge. This function also updates ScopInfo and RegionInfo.
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NewBlock = SplitEdge(R.getEnteringBlock(), R.getEntry(), PassInfo);
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if (DT.dominates(R.getEntry(), NewBlock)) {
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BasicBlock *OldBlock = R.getEntry();
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std::string OldName = OldBlock->getName();
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// Update ScopInfo.
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for (Scop::iterator SI = S.begin(), SE = S.end(); SI != SE; ++SI)
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if ((*SI)->getBasicBlock() == OldBlock) {
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(*SI)->setBasicBlock(NewBlock);
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break;
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}
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// Update RegionInfo.
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SplitBlock = OldBlock;
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OldBlock->setName("polly.split");
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NewBlock->setName(OldName);
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R.replaceEntry(NewBlock);
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RI.setRegionFor(NewBlock, &R);
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} else {
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RI.setRegionFor(NewBlock, R.getParent());
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SplitBlock = NewBlock;
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}
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SplitBlock->setName("polly.split_new_and_old");
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Function *F = SplitBlock->getParent();
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StartBlock = BasicBlock::Create(F->getContext(), "polly.start", F);
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SplitBlock->getTerminator()->eraseFromParent();
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Builder.SetInsertPoint(SplitBlock);
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Builder.CreateCondBr(Builder.getTrue(), StartBlock, R.getEntry());
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DT.addNewBlock(StartBlock, SplitBlock);
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Builder.SetInsertPoint(StartBlock);
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BasicBlock *MergeBlock;
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if (R.getExit()->getSinglePredecessor())
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// No splitEdge required. A block with a single predecessor cannot have
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// PHI nodes that would complicate life.
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MergeBlock = R.getExit();
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else {
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MergeBlock = SplitEdge(R.getExitingBlock(), R.getExit(), PassInfo);
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// SplitEdge will never split R.getExit(), as R.getExit() has more than
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// one predecessor. Hence, mergeBlock is always a newly generated block.
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R.replaceExit(MergeBlock);
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}
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Builder.CreateBr(MergeBlock);
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MergeBlock->setName("polly.merge_new_and_old");
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if (DT.dominates(SplitBlock, MergeBlock))
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DT.changeImmediateDominator(MergeBlock, SplitBlock);
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return StartBlock;
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}
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