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