- preserveCanonicalLoopForm(LPM);
-
- NumRotated++;
- return true;
-}
-
-/// Initialize local data
-void LoopRotate::initialize() {
- L = NULL;
- OrigHeader = NULL;
- OrigPreHeader = NULL;
- NewHeader = NULL;
- Exit = NULL;
-}
-
-/// After loop rotation, loop pre-header has multiple sucessors.
-/// Insert one forwarding basic block to ensure that loop pre-header
-/// has only one successor.
-void LoopRotate::preserveCanonicalLoopForm(LPPassManager &LPM) {
-
- // Right now original pre-header has two successors, new header and
- // exit block. Insert new block between original pre-header and
- // new header such that loop's new pre-header has only one successor.
- BasicBlock *NewPreHeader = BasicBlock::Create(OrigHeader->getContext(),
- "bb.nph",
- OrigHeader->getParent(),
- NewHeader);
- LoopInfo &LI = LPM.getAnalysis<LoopInfo>();
- if (Loop *PL = LI.getLoopFor(OrigPreHeader))
- PL->addBasicBlockToLoop(NewPreHeader, LI.getBase());
- BranchInst::Create(NewHeader, NewPreHeader);
-
- BranchInst *OrigPH_BI = cast<BranchInst>(OrigPreHeader->getTerminator());
- if (OrigPH_BI->getSuccessor(0) == NewHeader)
- OrigPH_BI->setSuccessor(0, NewPreHeader);
- else {
- assert(OrigPH_BI->getSuccessor(1) == NewHeader &&
- "Unexpected original pre-header terminator");
- OrigPH_BI->setSuccessor(1, NewPreHeader);
- }
-
- PHINode *PN;
- for (BasicBlock::iterator I = NewHeader->begin();
- (PN = dyn_cast<PHINode>(I)); ++I) {
- int index = PN->getBasicBlockIndex(OrigPreHeader);
- assert(index != -1 && "Expected incoming value from Original PreHeader");
- PN->setIncomingBlock(index, NewPreHeader);
- assert(PN->getBasicBlockIndex(OrigPreHeader) == -1 &&
- "Expected only one incoming value from Original PreHeader");
- }
-
- if (DominatorTree *DT = getAnalysisIfAvailable<DominatorTree>()) {
- DT->addNewBlock(NewPreHeader, OrigPreHeader);
- DT->changeImmediateDominator(L->getHeader(), NewPreHeader);
- DT->changeImmediateDominator(Exit, OrigPreHeader);
- for (Loop::block_iterator BI = L->block_begin(), BE = L->block_end();
- BI != BE; ++BI) {
- BasicBlock *B = *BI;
- if (L->getHeader() != B) {
- DomTreeNode *Node = DT->getNode(B);
- if (Node && Node->getBlock() == OrigHeader)
- DT->changeImmediateDominator(*BI, L->getHeader());
- }
- }
- DT->changeImmediateDominator(OrigHeader, OrigLatch);
- }
-
- if (DominanceFrontier *DF = getAnalysisIfAvailable<DominanceFrontier>()) {
- // New Preheader's dominance frontier is Exit block.
- DominanceFrontier::DomSetType NewPHSet;
- NewPHSet.insert(Exit);
- DF->addBasicBlock(NewPreHeader, NewPHSet);
-
- // New Header's dominance frontier now includes itself and Exit block
- DominanceFrontier::iterator HeadI = DF->find(L->getHeader());
- if (HeadI != DF->end()) {
- DominanceFrontier::DomSetType & HeaderSet = HeadI->second;
- HeaderSet.clear();
- HeaderSet.insert(L->getHeader());
- HeaderSet.insert(Exit);
- } else {
- DominanceFrontier::DomSetType HeaderSet;
- HeaderSet.insert(L->getHeader());
- HeaderSet.insert(Exit);
- DF->addBasicBlock(L->getHeader(), HeaderSet);
- }
-
- // Original header (new Loop Latch)'s dominance frontier is Exit.
- DominanceFrontier::iterator LatchI = DF->find(L->getLoopLatch());
- if (LatchI != DF->end()) {
- DominanceFrontier::DomSetType &LatchSet = LatchI->second;
- LatchSet = LatchI->second;
- LatchSet.clear();
- LatchSet.insert(Exit);
- } else {
- DominanceFrontier::DomSetType LatchSet;
- LatchSet.insert(Exit);
- DF->addBasicBlock(L->getHeader(), LatchSet);