diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Scalar/LoopUnswitch.cpp | 280 |
1 files changed, 140 insertions, 140 deletions
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp index 842802e..1c93a70 100644 --- a/lib/Transforms/Scalar/LoopUnswitch.cpp +++ b/lib/Transforms/Scalar/LoopUnswitch.cpp @@ -64,63 +64,63 @@ STATISTIC(TotalInsts, "Total number of instructions analyzed"); static cl::opt<unsigned> Threshold("loop-unswitch-threshold", cl::desc("Max loop size to unswitch"), cl::init(100), cl::Hidden); - + namespace { - + class LUAnalysisCache { typedef DenseMap<const SwitchInst*, SmallPtrSet<const Value *, 8> > UnswitchedValsMap; - + typedef UnswitchedValsMap::iterator UnswitchedValsIt; - + struct LoopProperties { unsigned CanBeUnswitchedCount; unsigned SizeEstimation; UnswitchedValsMap UnswitchedVals; }; - - // Here we use std::map instead of DenseMap, since we need to keep valid + + // Here we use std::map instead of DenseMap, since we need to keep valid // LoopProperties pointer for current loop for better performance. typedef std::map<const Loop*, LoopProperties> LoopPropsMap; typedef LoopPropsMap::iterator LoopPropsMapIt; - + LoopPropsMap LoopsProperties; UnswitchedValsMap* CurLoopInstructions; LoopProperties* CurrentLoopProperties; - + // Max size of code we can produce on remained iterations. unsigned MaxSize; - + public: - + LUAnalysisCache() : CurLoopInstructions(NULL), CurrentLoopProperties(NULL), MaxSize(Threshold) {} - + // Analyze loop. Check its size, calculate is it possible to unswitch // it. Returns true if we can unswitch this loop. bool countLoop(const Loop* L); - + // Clean all data related to given loop. void forgetLoop(const Loop* L); - + // Mark case value as unswitched. // Since SI instruction can be partly unswitched, in order to avoid // extra unswitching in cloned loops keep track all unswitched values. void setUnswitched(const SwitchInst* SI, const Value* V); - + // Check was this case value unswitched before or not. bool isUnswitched(const SwitchInst* SI, const Value* V); - + // Clone all loop-unswitch related loop properties. // Redistribute unswitching quotas. // Note, that new loop data is stored inside the VMap. void cloneData(const Loop* NewLoop, const Loop* OldLoop, const ValueToValueMapTy& VMap); }; - + class LoopUnswitch : public LoopPass { LoopInfo *LI; // Loop information LPPassManager *LPM; @@ -130,7 +130,7 @@ namespace { std::vector<Loop*> LoopProcessWorklist; LUAnalysisCache BranchesInfo; - + bool OptimizeForSize; bool redoLoop; @@ -138,9 +138,9 @@ namespace { DominatorTree *DT; BasicBlock *loopHeader; BasicBlock *loopPreheader; - + // LoopBlocks contains all of the basic blocks of the loop, including the - // preheader of the loop, the body of the loop, and the exit blocks of the + // preheader of the loop, the body of the loop, and the exit blocks of the // loop, in that order. std::vector<BasicBlock*> LoopBlocks; // NewBlocks contained cloned copy of basic blocks from LoopBlocks. @@ -148,8 +148,8 @@ namespace { public: static char ID; // Pass ID, replacement for typeid - explicit LoopUnswitch(bool Os = false) : - LoopPass(ID), OptimizeForSize(Os), redoLoop(false), + explicit LoopUnswitch(bool Os = false) : + LoopPass(ID), OptimizeForSize(Os), redoLoop(false), currentLoop(NULL), DT(NULL), loopHeader(NULL), loopPreheader(NULL) { initializeLoopUnswitchPass(*PassRegistry::getPassRegistry()); @@ -186,14 +186,14 @@ namespace { if (I != LoopProcessWorklist.end()) LoopProcessWorklist.erase(I); } - + void initLoopData() { loopHeader = currentLoop->getHeader(); loopPreheader = currentLoop->getLoopPreheader(); } - + /// HasIndirectBrsInPreds - Returns true if there are predecessors, that are - /// terminated with indirect branch instruction. + /// terminated with indirect branch instruction. bool HasIndirectBrsInPreds(const SmallVectorImpl<BasicBlock *> &ExitBlocks); /// Split all of the edges from inside the loop to their exit blocks. @@ -209,7 +209,7 @@ namespace { Constant *Val, bool isEqual); void EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val, - BasicBlock *TrueDest, + BasicBlock *TrueDest, BasicBlock *FalseDest, Instruction *InsertPt); @@ -226,12 +226,12 @@ namespace { // Analyze loop. Check its size, calculate is it possible to unswitch // it. Returns true if we can unswitch this loop. bool LUAnalysisCache::countLoop(const Loop* L) { - + std::pair<LoopPropsMapIt, bool> InsertRes = LoopsProperties.insert(std::make_pair(L, LoopProperties())); - + LoopProperties& Props = InsertRes.first->second; - + if (InsertRes.second) { // New loop. @@ -239,39 +239,39 @@ bool LUAnalysisCache::countLoop(const Loop* L) { // expansion, and the number of basic blocks, to avoid loops with // large numbers of branches which cause loop unswitching to go crazy. // This is a very ad-hoc heuristic. - + // FIXME: This is overly conservative because it does not take into // consideration code simplification opportunities and code that can // be shared by the resultant unswitched loops. CodeMetrics Metrics; - for (Loop::block_iterator I = L->block_begin(), + for (Loop::block_iterator I = L->block_begin(), E = L->block_end(); I != E; ++I) - Metrics.analyzeBasicBlock(*I); + Metrics.analyzeBasicBlock(*I); Props.SizeEstimation = std::min(Metrics.NumInsts, Metrics.NumBlocks * 5); Props.CanBeUnswitchedCount = MaxSize / (Props.SizeEstimation); MaxSize -= Props.SizeEstimation * Props.CanBeUnswitchedCount; - } - + } + if (!Props.CanBeUnswitchedCount) { DEBUG(dbgs() << "NOT unswitching loop %" << L->getHeader()->getName() << ", cost too high: " << L->getBlocks().size() << "\n"); - + return false; } - + // Be careful. This links are good only before new loop addition. CurrentLoopProperties = &Props; CurLoopInstructions = &Props.UnswitchedVals; - + return true; } // Clean all data related to given loop. void LUAnalysisCache::forgetLoop(const Loop* L) { - + LoopPropsMapIt LIt = LoopsProperties.find(L); if (LIt != LoopsProperties.end()) { @@ -279,9 +279,9 @@ void LUAnalysisCache::forgetLoop(const Loop* L) { MaxSize += Props.CanBeUnswitchedCount * Props.SizeEstimation; LoopsProperties.erase(LIt); } - + CurrentLoopProperties = NULL; - CurLoopInstructions = NULL; + CurLoopInstructions = NULL; } // Mark case value as unswitched. @@ -293,7 +293,7 @@ void LUAnalysisCache::setUnswitched(const SwitchInst* SI, const Value* V) { // Check was this case value unswitched before or not. bool LUAnalysisCache::isUnswitched(const SwitchInst* SI, const Value* V) { - return (*CurLoopInstructions)[SI].count(V); + return (*CurLoopInstructions)[SI].count(V); } // Clone all loop-unswitch related loop properties. @@ -301,20 +301,20 @@ bool LUAnalysisCache::isUnswitched(const SwitchInst* SI, const Value* V) { // Note, that new loop data is stored inside the VMap. void LUAnalysisCache::cloneData(const Loop* NewLoop, const Loop* OldLoop, const ValueToValueMapTy& VMap) { - + LoopProperties& NewLoopProps = LoopsProperties[NewLoop]; LoopProperties& OldLoopProps = *CurrentLoopProperties; UnswitchedValsMap& Insts = OldLoopProps.UnswitchedVals; - + // Reallocate "can-be-unswitched quota" --OldLoopProps.CanBeUnswitchedCount; unsigned Quota = OldLoopProps.CanBeUnswitchedCount; NewLoopProps.CanBeUnswitchedCount = Quota / 2; OldLoopProps.CanBeUnswitchedCount = Quota - Quota / 2; - + NewLoopProps.SizeEstimation = OldLoopProps.SizeEstimation; - + // Clone unswitched values info: // for new loop switches we clone info about values that was // already unswitched and has redundant successors. @@ -323,7 +323,7 @@ void LUAnalysisCache::cloneData(const Loop* NewLoop, const Loop* OldLoop, Value* NewI = VMap.lookup(OldInst); const SwitchInst* NewInst = cast_or_null<SwitchInst>(NewI); assert(NewInst && "All instructions that are in SrcBB must be in VMap."); - + NewLoopProps.UnswitchedVals[NewInst] = OldLoopProps.UnswitchedVals[OldInst]; } } @@ -337,18 +337,18 @@ INITIALIZE_PASS_DEPENDENCY(LCSSA) INITIALIZE_PASS_END(LoopUnswitch, "loop-unswitch", "Unswitch loops", false, false) -Pass *llvm::createLoopUnswitchPass(bool Os) { - return new LoopUnswitch(Os); +Pass *llvm::createLoopUnswitchPass(bool Os) { + return new LoopUnswitch(Os); } /// FindLIVLoopCondition - Cond is a condition that occurs in L. If it is /// invariant in the loop, or has an invariant piece, return the invariant. /// Otherwise, return null. static Value *FindLIVLoopCondition(Value *Cond, Loop *L, bool &Changed) { - + // We started analyze new instruction, increment scanned instructions counter. ++TotalInsts; - + // We can never unswitch on vector conditions. if (Cond->getType()->isVectorTy()) return 0; @@ -373,7 +373,7 @@ static Value *FindLIVLoopCondition(Value *Cond, Loop *L, bool &Changed) { if (Value *RHS = FindLIVLoopCondition(BO->getOperand(1), L, Changed)) return RHS; } - + return 0; } @@ -398,19 +398,19 @@ bool LoopUnswitch::runOnLoop(Loop *L, LPPassManager &LPM_Ref) { return Changed; } -/// processCurrentLoop - Do actual work and unswitch loop if possible +/// processCurrentLoop - Do actual work and unswitch loop if possible /// and profitable. bool LoopUnswitch::processCurrentLoop() { bool Changed = false; initLoopData(); - + // If LoopSimplify was unable to form a preheader, don't do any unswitching. if (!loopPreheader) return false; - + LLVMContext &Context = loopHeader->getContext(); - + // Probably we reach the quota of branches for this loop. If so // stop unswitching. if (!BranchesInfo.countLoop(currentLoop)) @@ -419,7 +419,7 @@ bool LoopUnswitch::processCurrentLoop() { // Loop over all of the basic blocks in the loop. If we find an interior // block that is branching on a loop-invariant condition, we can unswitch this // loop. - for (Loop::block_iterator I = currentLoop->block_begin(), + for (Loop::block_iterator I = currentLoop->block_begin(), E = currentLoop->block_end(); I != E; ++I) { TerminatorInst *TI = (*I)->getTerminator(); if (BranchInst *BI = dyn_cast<BranchInst>(TI)) { @@ -428,24 +428,24 @@ bool LoopUnswitch::processCurrentLoop() { if (BI->isConditional()) { // See if this, or some part of it, is loop invariant. If so, we can // unswitch on it if we desire. - Value *LoopCond = FindLIVLoopCondition(BI->getCondition(), + Value *LoopCond = FindLIVLoopCondition(BI->getCondition(), currentLoop, Changed); - if (LoopCond && UnswitchIfProfitable(LoopCond, + if (LoopCond && UnswitchIfProfitable(LoopCond, ConstantInt::getTrue(Context))) { ++NumBranches; return true; } - } + } } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) { - Value *LoopCond = FindLIVLoopCondition(SI->getCondition(), + Value *LoopCond = FindLIVLoopCondition(SI->getCondition(), currentLoop, Changed); - unsigned NumCases = SI->getNumCases(); + unsigned NumCases = SI->getNumCases(); if (LoopCond && NumCases) { // Find a value to unswitch on: // FIXME: this should chose the most expensive case! // FIXME: scan for a case with a non-critical edge? Constant *UnswitchVal = NULL; - + // Do not process same value again and again. // At this point we have some cases already unswitched and // some not yet unswitched. Let's find the first not yet unswitched one. @@ -457,7 +457,7 @@ bool LoopUnswitch::processCurrentLoop() { break; } } - + if (!UnswitchVal) continue; @@ -467,14 +467,14 @@ bool LoopUnswitch::processCurrentLoop() { } } } - + // Scan the instructions to check for unswitchable values. - for (BasicBlock::iterator BBI = (*I)->begin(), E = (*I)->end(); + for (BasicBlock::iterator BBI = (*I)->begin(), E = (*I)->end(); BBI != E; ++BBI) if (SelectInst *SI = dyn_cast<SelectInst>(BBI)) { - Value *LoopCond = FindLIVLoopCondition(SI->getCondition(), + Value *LoopCond = FindLIVLoopCondition(SI->getCondition(), currentLoop, Changed); - if (LoopCond && UnswitchIfProfitable(LoopCond, + if (LoopCond && UnswitchIfProfitable(LoopCond, ConstantInt::getTrue(Context))) { ++NumSelects; return true; @@ -504,7 +504,7 @@ static bool isTrivialLoopExitBlockHelper(Loop *L, BasicBlock *BB, ExitBB = BB; return true; } - + // Otherwise, this is an unvisited intra-loop node. Check all successors. for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI) { // Check to see if the successor is a trivial loop exit. @@ -517,12 +517,12 @@ static bool isTrivialLoopExitBlockHelper(Loop *L, BasicBlock *BB, for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) if (I->mayHaveSideEffects()) return false; - + return true; } /// isTrivialLoopExitBlock - Return true if the specified block unconditionally -/// leads to an exit from the specified loop, and has no side-effects in the +/// leads to an exit from the specified loop, and has no side-effects in the /// process. If so, return the block that is exited to, otherwise return null. static BasicBlock *isTrivialLoopExitBlock(Loop *L, BasicBlock *BB) { std::set<BasicBlock*> Visited; @@ -550,39 +550,39 @@ bool LoopUnswitch::IsTrivialUnswitchCondition(Value *Cond, Constant **Val, BasicBlock *Header = currentLoop->getHeader(); TerminatorInst *HeaderTerm = Header->getTerminator(); LLVMContext &Context = Header->getContext(); - + BasicBlock *LoopExitBB = 0; if (BranchInst *BI = dyn_cast<BranchInst>(HeaderTerm)) { // If the header block doesn't end with a conditional branch on Cond, we // can't handle it. if (!BI->isConditional() || BI->getCondition() != Cond) return false; - - // Check to see if a successor of the branch is guaranteed to - // exit through a unique exit block without having any + + // Check to see if a successor of the branch is guaranteed to + // exit through a unique exit block without having any // side-effects. If so, determine the value of Cond that causes it to do // this. - if ((LoopExitBB = isTrivialLoopExitBlock(currentLoop, + if ((LoopExitBB = isTrivialLoopExitBlock(currentLoop, BI->getSuccessor(0)))) { if (Val) *Val = ConstantInt::getTrue(Context); - } else if ((LoopExitBB = isTrivialLoopExitBlock(currentLoop, + } else if ((LoopExitBB = isTrivialLoopExitBlock(currentLoop, BI->getSuccessor(1)))) { if (Val) *Val = ConstantInt::getFalse(Context); } } else if (SwitchInst *SI = dyn_cast<SwitchInst>(HeaderTerm)) { // If this isn't a switch on Cond, we can't handle it. if (SI->getCondition() != Cond) return false; - + // Check to see if a successor of the switch is guaranteed to go to the - // latch block or exit through a one exit block without having any + // latch block or exit through a one exit block without having any // side-effects. If so, determine the value of Cond that causes it to do - // this. + // this. // Note that we can't trivially unswitch on the default case or // on already unswitched cases. for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end(); i != e; ++i) { BasicBlock* LoopExitCandidate; - if ((LoopExitCandidate = isTrivialLoopExitBlock(currentLoop, + if ((LoopExitCandidate = isTrivialLoopExitBlock(currentLoop, i.getCaseSuccessor()))) { // Okay, we found a trivial case, remember the value that is trivial. ConstantInt* CaseVal = i.getCaseValue(); @@ -602,9 +602,9 @@ bool LoopUnswitch::IsTrivialUnswitchCondition(Value *Cond, Constant **Val, // contains phi nodes, this isn't trivial. if (!LoopExitBB || isa<PHINode>(LoopExitBB->begin())) return false; // Can't handle this. - + if (LoopExit) *LoopExit = LoopExitBB; - + // We already know that nothing uses any scalar values defined inside of this // loop. As such, we just have to check to see if this loop will execute any // side-effecting instructions (e.g. stores, calls, volatile loads) in the @@ -689,17 +689,17 @@ void LoopUnswitch::EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val, /// UnswitchTrivialCondition - Given a loop that has a trivial unswitchable /// condition in it (a cond branch from its header block to its latch block, -/// where the path through the loop that doesn't execute its body has no +/// where the path through the loop that doesn't execute its body has no /// side-effects), unswitch it. This doesn't involve any code duplication, just /// moving the conditional branch outside of the loop and updating loop info. -void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, - Constant *Val, +void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, + Constant *Val, BasicBlock *ExitBlock) { DEBUG(dbgs() << "loop-unswitch: Trivial-Unswitch loop %" << loopHeader->getName() << " [" << L->getBlocks().size() << " blocks] in Function " << L->getHeader()->getParent()->getName() << " on cond: " << *Val << " == " << *Cond << "\n"); - + // First step, split the preheader, so that we know that there is a safe place // to insert the conditional branch. We will change loopPreheader to have a // conditional branch on Cond. @@ -708,24 +708,24 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, // Now that we have a place to insert the conditional branch, create a place // to branch to: this is the exit block out of the loop that we should // short-circuit to. - + // Split this block now, so that the loop maintains its exit block, and so // that the jump from the preheader can execute the contents of the exit block // without actually branching to it (the exit block should be dominated by the // loop header, not the preheader). assert(!L->contains(ExitBlock) && "Exit block is in the loop?"); BasicBlock *NewExit = SplitBlock(ExitBlock, ExitBlock->begin(), this); - - // Okay, now we have a position to branch from and a position to branch to, + + // Okay, now we have a position to branch from and a position to branch to, // insert the new conditional branch. - EmitPreheaderBranchOnCondition(Cond, Val, NewExit, NewPH, + EmitPreheaderBranchOnCondition(Cond, Val, NewExit, NewPH, loopPreheader->getTerminator()); LPM->deleteSimpleAnalysisValue(loopPreheader->getTerminator(), L); loopPreheader->getTerminator()->eraseFromParent(); // We need to reprocess this loop, it could be unswitched again. redoLoop = true; - + // Now that we know that the loop is never entered when this condition is a // particular value, rewrite the loop with this info. We know that this will // at least eliminate the old branch. @@ -737,7 +737,7 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, /// terminated with indirect branch instruction. bool LoopUnswitch::HasIndirectBrsInPreds( const SmallVectorImpl<BasicBlock *> &ExitBlocks){ - + for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) { const BasicBlock *ExitBlock = ExitBlocks[i]; for (const_pred_iterator p = pred_begin(ExitBlock), e = pred_end(ExitBlock); @@ -745,7 +745,7 @@ bool LoopUnswitch::HasIndirectBrsInPreds( // Cannot split an edge from an IndirectBrInst if (isa<IndirectBrInst>((*p)->getTerminator())) return true; - + } } return false; @@ -753,7 +753,7 @@ bool LoopUnswitch::HasIndirectBrsInPreds( /// SplitExitEdges - Split all of the edges from inside the loop to their exit /// blocks. Update the appropriate Phi nodes as we do so. -void LoopUnswitch::SplitExitEdges(Loop *L, +void LoopUnswitch::SplitExitEdges(Loop *L, const SmallVector<BasicBlock *, 8> &ExitBlocks){ for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) { @@ -773,10 +773,10 @@ void LoopUnswitch::SplitExitEdges(Loop *L, } } -/// UnswitchNontrivialCondition - We determined that the loop is profitable -/// to unswitch when LIC equal Val. Split it into loop versions and test the +/// UnswitchNontrivialCondition - We determined that the loop is profitable +/// to unswitch when LIC equal Val. Split it into loop versions and test the /// condition outside of either loop. Return the loops created as Out1/Out2. -bool LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val, +bool LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val, Loop *L) { Function *F = loopHeader->getParent(); DEBUG(dbgs() << "loop-unswitch: Unswitching loop %" @@ -821,7 +821,7 @@ bool LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val, ValueToValueMapTy VMap; for (unsigned i = 0, e = LoopBlocks.size(); i != e; ++i) { BasicBlock *NewBB = CloneBasicBlock(LoopBlocks[i], VMap, ".us", F); - + NewBlocks.push_back(NewBB); VMap[LoopBlocks[i]] = NewBB; // Keep the BB mapping. LPM->cloneBasicBlockSimpleAnalysis(LoopBlocks[i], NewBB, L); @@ -851,7 +851,7 @@ bool LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val, // The new exit block should be in the same loop as the old one. if (Loop *ExitBBLoop = LI->getLoopFor(ExitBlocks[i])) ExitBBLoop->addBasicBlockToLoop(NewExit, LI->getBase()); - + assert(NewExit->getTerminator()->getNumSuccessors() == 1 && "Exit block should have been split to have one successor!"); BasicBlock *ExitSucc = NewExit->getTerminator()->getSuccessor(0); @@ -886,7 +886,7 @@ bool LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val, for (BasicBlock::iterator I = NewBlocks[i]->begin(), E = NewBlocks[i]->end(); I != E; ++I) RemapInstruction(I, VMap,RF_NoModuleLevelChanges|RF_IgnoreMissingEntries); - + // Rewrite the original preheader to select between versions of the loop. BranchInst *OldBR = cast<BranchInst>(loopPreheader->getTerminator()); assert(OldBR->isUnconditional() && OldBR->getSuccessor(0) == LoopBlocks[0] && @@ -905,7 +905,7 @@ bool LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val, // the condition that we're unswitching on), we don't rewrite the second // iteration. WeakVH LICHandle(LIC); - + // Now we rewrite the original code to know that the condition is true and the // new code to know that the condition is false. RewriteLoopBodyWithConditionConstant(L, LIC, Val, false); @@ -916,13 +916,13 @@ bool LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val, if (!LoopProcessWorklist.empty() && LoopProcessWorklist.back() == NewLoop && LICHandle && !isa<Constant>(LICHandle)) RewriteLoopBodyWithConditionConstant(NewLoop, LICHandle, Val, true); - + return true; } /// RemoveFromWorklist - Remove all instances of I from the worklist vector /// specified. -static void RemoveFromWorklist(Instruction *I, +static void RemoveFromWorklist(Instruction *I, std::vector<Instruction*> &Worklist) { std::vector<Instruction*>::iterator WI = std::find(Worklist.begin(), Worklist.end(), I); @@ -935,7 +935,7 @@ static void RemoveFromWorklist(Instruction *I, /// ReplaceUsesOfWith - When we find that I really equals V, remove I from the /// program, replacing all uses with V and update the worklist. -static void ReplaceUsesOfWith(Instruction *I, Value *V, +static void ReplaceUsesOfWith(Instruction *I, Value *V, std::vector<Instruction*> &Worklist, Loop *L, LPPassManager *LPM) { DEBUG(dbgs() << "Replace with '" << *V << "': " << *I); @@ -968,10 +968,10 @@ void LoopUnswitch::RemoveBlockIfDead(BasicBlock *BB, if (BasicBlock *Pred = BB->getSinglePredecessor()) { // If it has one pred, fold phi nodes in BB. while (isa<PHINode>(BB->begin())) - ReplaceUsesOfWith(BB->begin(), - cast<PHINode>(BB->begin())->getIncomingValue(0), + ReplaceUsesOfWith(BB->begin(), + cast<PHINode>(BB->begin())->getIncomingValue(0), Worklist, L, LPM); - + // If this is the header of a loop and the only pred is the latch, we now // have an unreachable loop. if (Loop *L = LI->getLoopFor(BB)) @@ -982,15 +982,15 @@ void LoopUnswitch::RemoveBlockIfDead(BasicBlock *BB, LPM->deleteSimpleAnalysisValue(Pred->getTerminator(), L); Pred->getTerminator()->eraseFromParent(); new UnreachableInst(BB->getContext(), Pred); - + // The loop is now broken, remove it from LI. RemoveLoopFromHierarchy(L); - + // Reprocess the header, which now IS dead. RemoveBlockIfDead(BB, Worklist, L); return; } - + // If pred ends in a uncond branch, add uncond branch to worklist so that // the two blocks will get merged. if (BranchInst *BI = dyn_cast<BranchInst>(Pred->getTerminator())) @@ -1001,11 +1001,11 @@ void LoopUnswitch::RemoveBlockIfDead(BasicBlock *BB, } DEBUG(dbgs() << "Nuking dead block: " << *BB); - + // Remove the instructions in the basic block from the worklist. for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { RemoveFromWorklist(I, Worklist); - + // Anything that uses the instructions in this basic block should have their // uses replaced with undefs. // If I is not void type then replaceAllUsesWith undef. @@ -1013,7 +1013,7 @@ void LoopUnswitch::RemoveBlockIfDead(BasicBlock *BB, if (!I->getType()->isVoidTy()) I->replaceAllUsesWith(UndefValue::get(I->getType())); } - + // If this is the edge to the header block for a loop, remove the loop and // promote all subloops. if (Loop *BBLoop = LI->getLoopFor(BB)) { @@ -1029,8 +1029,8 @@ void LoopUnswitch::RemoveBlockIfDead(BasicBlock *BB, // Remove the block from the loop info, which removes it from any loops it // was in. LI->removeBlock(BB); - - + + // Remove phi node entries in successors for this block. TerminatorInst *TI = BB->getTerminator(); SmallVector<BasicBlock*, 4> Succs; @@ -1038,13 +1038,13 @@ void LoopUnswitch::RemoveBlockIfDead(BasicBlock *BB, Succs.push_back(TI->getSuccessor(i)); TI->getSuccessor(i)->removePredecessor(BB); } - + // Unique the successors, remove anything with multiple uses. array_pod_sort(Succs.begin(), Succs.end()); Succs.erase(std::unique(Succs.begin(), Succs.end()), Succs.end()); - + // Remove the basic block, including all of the instructions contained in it. - LPM->deleteSimpleAnalysisValue(BB, L); + LPM->deleteSimpleAnalysisValue(BB, L); BB->eraseFromParent(); // Remove successor blocks here that are not dead, so that we know we only // have dead blocks in this list. Nondead blocks have a way of becoming dead, @@ -1062,7 +1062,7 @@ void LoopUnswitch::RemoveBlockIfDead(BasicBlock *BB, --i; } } - + for (unsigned i = 0, e = Succs.size(); i != e; ++i) RemoveBlockIfDead(Succs[i], Worklist, L); } @@ -1085,14 +1085,14 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC, Constant *Val, bool IsEqual) { assert(!isa<Constant>(LIC) && "Why are we unswitching on a constant?"); - + // FIXME: Support correlated properties, like: // for (...) // if (li1 < li2) // ... // if (li1 > li2) // ... - + // FOLD boolean conditions (X|LIC), (X&LIC). Fold conditional branches, // selects, switches. std::vector<Instruction*> Worklist; @@ -1107,9 +1107,9 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC, if (IsEqual) Replacement = Val; else - Replacement = ConstantInt::get(Type::getInt1Ty(Val->getContext()), + Replacement = ConstantInt::get(Type::getInt1Ty(Val->getContext()), !cast<ConstantInt>(Val)->getZExtValue()); - + for (Value::use_iterator UI = LIC->use_begin(), E = LIC->use_end(); UI != E; ++UI) { Instruction *U = dyn_cast<Instruction>(*UI); @@ -1117,15 +1117,15 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC, continue; Worklist.push_back(U); } - + for (std::vector<Instruction*>::iterator UI = Worklist.begin(); UI != Worklist.end(); ++UI) - (*UI)->replaceUsesOfWith(LIC, Replacement); - + (*UI)->replaceUsesOfWith(LIC, Replacement); + SimplifyCode(Worklist, L); return; } - + // Otherwise, we don't know the precise value of LIC, but we do know that it // is certainly NOT "Val". As such, simplify any uses in the loop that we // can. This case occurs when we unswitch switch statements. @@ -1137,27 +1137,27 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC, Worklist.push_back(U); - // TODO: We could do other simplifications, for example, turning + // TODO: We could do other simplifications, for example, turning // 'icmp eq LIC, Val' -> false. // If we know that LIC is not Val, use this info to simplify code. SwitchInst *SI = dyn_cast<SwitchInst>(U); if (SI == 0 || !isa<ConstantInt>(Val)) continue; - + SwitchInst::CaseIt DeadCase = SI->findCaseValue(cast<ConstantInt>(Val)); // Default case is live for multiple values. if (DeadCase == SI->case_default()) continue; - - // Found a dead case value. Don't remove PHI nodes in the + + // Found a dead case value. Don't remove PHI nodes in the // successor if they become single-entry, those PHI nodes may // be in the Users list. BasicBlock *Switch = SI->getParent(); BasicBlock *SISucc = DeadCase.getCaseSuccessor(); BasicBlock *Latch = L->getLoopLatch(); - + BranchesInfo.setUnswitched(SI, Val); - + if (!SI->findCaseDest(SISucc)) continue; // Edge is critical. // If the DeadCase successor dominates the loop latch, then the // transformation isn't safe since it will delete the sole predecessor edge @@ -1197,7 +1197,7 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC, if (DT) DT->addNewBlock(Abort, NewSISucc); } - + SimplifyCode(Worklist, L); } @@ -1218,7 +1218,7 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) { // Simple DCE. if (isInstructionTriviallyDead(I)) { DEBUG(dbgs() << "Remove dead instruction '" << *I); - + // Add uses to the worklist, which may be dead now. for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) if (Instruction *Use = dyn_cast<Instruction>(I->getOperand(i))) @@ -1250,24 +1250,24 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) { if (!SinglePred) continue; // Nothing to do. assert(SinglePred == Pred && "CFG broken"); - DEBUG(dbgs() << "Merging blocks: " << Pred->getName() << " <- " + DEBUG(dbgs() << "Merging blocks: " << Pred->getName() << " <- " << Succ->getName() << "\n"); - + // Resolve any single entry PHI nodes in Succ. while (PHINode *PN = dyn_cast<PHINode>(Succ->begin())) ReplaceUsesOfWith(PN, PN->getIncomingValue(0), Worklist, L, LPM); - + // If Succ has any successors with PHI nodes, update them to have // entries coming from Pred instead of Succ. Succ->replaceAllUsesWith(Pred); - + // Move all of the successor contents from Succ to Pred. Pred->getInstList().splice(BI, Succ->getInstList(), Succ->begin(), Succ->end()); LPM->deleteSimpleAnalysisValue(BI, L); BI->eraseFromParent(); RemoveFromWorklist(BI, Worklist); - + // Remove Succ from the loop tree. LI->removeBlock(Succ); LPM->deleteSimpleAnalysisValue(Succ, L); @@ -1275,7 +1275,7 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) { ++NumSimplify; continue; } - + if (ConstantInt *CB = dyn_cast<ConstantInt>(BI->getCondition())){ // Conditional branch. Turn it into an unconditional branch, then // remove dead blocks. |