diff options
Diffstat (limited to 'lib/Transforms/Scalar/LICM.cpp')
-rw-r--r-- | lib/Transforms/Scalar/LICM.cpp | 51 |
1 files changed, 28 insertions, 23 deletions
diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp index d6daeca1128c..756fbf3e7bd5 100644 --- a/lib/Transforms/Scalar/LICM.cpp +++ b/lib/Transforms/Scalar/LICM.cpp @@ -35,8 +35,8 @@ #include "llvm/Transforms/Scalar.h" #include "llvm/Constants.h" #include "llvm/DerivedTypes.h" +#include "llvm/IntrinsicInst.h" #include "llvm/Instructions.h" -#include "llvm/LLVMContext.h" #include "llvm/Target/TargetData.h" #include "llvm/Analysis/LoopInfo.h" #include "llvm/Analysis/LoopPass.h" @@ -46,8 +46,8 @@ #include "llvm/Analysis/ScalarEvolution.h" #include "llvm/Transforms/Utils/PromoteMemToReg.h" #include "llvm/Support/CFG.h" -#include "llvm/Support/Compiler.h" #include "llvm/Support/CommandLine.h" +#include "llvm/Support/raw_ostream.h" #include "llvm/Support/Debug.h" #include "llvm/ADT/Statistic.h" #include <algorithm> @@ -73,7 +73,7 @@ EnableLICMConstantMotion("enable-licm-constant-variables", cl::Hidden, "global variables")); namespace { - struct VISIBILITY_HIDDEN LICM : public LoopPass { + struct LICM : public LoopPass { static char ID; // Pass identification, replacement for typeid LICM() : LoopPass(&ID) {} @@ -91,6 +91,7 @@ namespace { AU.addRequired<AliasAnalysis>(); AU.addPreserved<ScalarEvolution>(); AU.addPreserved<DominanceFrontier>(); + AU.addPreservedID(LoopSimplifyID); } bool doFinalization() { @@ -338,7 +339,6 @@ void LICM::SinkRegion(DomTreeNode *N) { } } - /// HoistRegion - Walk the specified region of the CFG (defined by all blocks /// dominated by the specified block, and that are in the current loop) in depth /// first order w.r.t the DominatorTree. This allows us to visit definitions @@ -389,9 +389,13 @@ bool LICM::canSinkOrHoistInst(Instruction &I) { // Don't hoist loads which have may-aliased stores in loop. unsigned Size = 0; if (LI->getType()->isSized()) - Size = AA->getTargetData().getTypeStoreSize(LI->getType()); + Size = AA->getTypeStoreSize(LI->getType()); return !pointerInvalidatedByLoop(LI->getOperand(0), Size); } else if (CallInst *CI = dyn_cast<CallInst>(&I)) { + if (isa<DbgStopPointInst>(CI)) { + // Don't hoist/sink dbgstoppoints, we handle them separately + return false; + } // Handle obvious cases efficiently. AliasAnalysis::ModRefBehavior Behavior = AA->getModRefBehavior(CI); if (Behavior == AliasAnalysis::DoesNotAccessMemory) @@ -465,7 +469,7 @@ bool LICM::isLoopInvariantInst(Instruction &I) { /// position, and may either delete it or move it to outside of the loop. /// void LICM::sink(Instruction &I) { - DOUT << "LICM sinking instruction: " << I; + DEBUG(errs() << "LICM sinking instruction: " << I); SmallVector<BasicBlock*, 8> ExitBlocks; CurLoop->getExitBlocks(ExitBlocks); @@ -482,22 +486,27 @@ void LICM::sink(Instruction &I) { if (!isExitBlockDominatedByBlockInLoop(ExitBlocks[0], I.getParent())) { // Instruction is not used, just delete it. CurAST->deleteValue(&I); - if (!I.use_empty()) // If I has users in unreachable blocks, eliminate. - I.replaceAllUsesWith(Context->getUndef(I.getType())); + // If I has users in unreachable blocks, eliminate. + // If I is not void type then replaceAllUsesWith undef. + // This allows ValueHandlers and custom metadata to adjust itself. + if (!I.getType()->isVoidTy()) + I.replaceAllUsesWith(UndefValue::get(I.getType())); I.eraseFromParent(); } else { // Move the instruction to the start of the exit block, after any PHI // nodes in it. I.removeFromParent(); - BasicBlock::iterator InsertPt = ExitBlocks[0]->getFirstNonPHI(); ExitBlocks[0]->getInstList().insert(InsertPt, &I); } } else if (ExitBlocks.empty()) { // The instruction is actually dead if there ARE NO exit blocks. CurAST->deleteValue(&I); - if (!I.use_empty()) // If I has users in unreachable blocks, eliminate. - I.replaceAllUsesWith(Context->getUndef(I.getType())); + // If I has users in unreachable blocks, eliminate. + // If I is not void type then replaceAllUsesWith undef. + // This allows ValueHandlers and custom metadata to adjust itself. + if (!I.getType()->isVoidTy()) + I.replaceAllUsesWith(UndefValue::get(I.getType())); I.eraseFromParent(); } else { // Otherwise, if we have multiple exits, use the PromoteMem2Reg function to @@ -507,7 +516,7 @@ void LICM::sink(Instruction &I) { // Firstly, we create a stack object to hold the value... AllocaInst *AI = 0; - if (I.getType() != Type::VoidTy) { + if (!I.getType()->isVoidTy()) { AI = new AllocaInst(I.getType(), 0, I.getName(), I.getParent()->getParent()->getEntryBlock().begin()); CurAST->add(AI); @@ -593,7 +602,7 @@ void LICM::sink(Instruction &I) { if (AI) { std::vector<AllocaInst*> Allocas; Allocas.push_back(AI); - PromoteMemToReg(Allocas, *DT, *DF, CurAST); + PromoteMemToReg(Allocas, *DT, *DF, AI->getContext(), CurAST); } } } @@ -602,7 +611,8 @@ void LICM::sink(Instruction &I) { /// that is safe to hoist, this instruction is called to do the dirty work. /// void LICM::hoist(Instruction &I) { - DOUT << "LICM hoisting to " << Preheader->getName() << ": " << I; + DEBUG(errs() << "LICM hoisting to " << Preheader->getName() << ": " + << I << "\n"); // Remove the instruction from its current basic block... but don't delete the // instruction. @@ -623,7 +633,8 @@ void LICM::hoist(Instruction &I) { /// bool LICM::isSafeToExecuteUnconditionally(Instruction &Inst) { // If it is not a trapping instruction, it is always safe to hoist. - if (!Inst.isTrapping()) return true; + if (Inst.isSafeToSpeculativelyExecute()) + return true; // Otherwise we have to check to make sure that the instruction dominates all // of the exit blocks. If it doesn't, then there is a path out of the loop @@ -635,12 +646,6 @@ bool LICM::isSafeToExecuteUnconditionally(Instruction &Inst) { if (Inst.getParent() == CurLoop->getHeader()) return true; - // It's always safe to load from a global or alloca. - if (isa<LoadInst>(Inst)) - if (isa<AllocationInst>(Inst.getOperand(0)) || - isa<GlobalVariable>(Inst.getOperand(0))) - return true; - // Get the exit blocks for the current loop. SmallVector<BasicBlock*, 8> ExitBlocks; CurLoop->getExitBlocks(ExitBlocks); @@ -773,7 +778,7 @@ void LICM::PromoteValuesInLoop() { PromotedAllocas.reserve(PromotedValues.size()); for (unsigned i = 0, e = PromotedValues.size(); i != e; ++i) PromotedAllocas.push_back(PromotedValues[i].first); - PromoteMemToReg(PromotedAllocas, *DT, *DF, CurAST); + PromoteMemToReg(PromotedAllocas, *DT, *DF, Preheader->getContext(), CurAST); } /// FindPromotableValuesInLoop - Check the current loop for stores to definite @@ -862,7 +867,7 @@ void LICM::FindPromotableValuesInLoop( for (AliasSet::iterator I = AS.begin(), E = AS.end(); I != E; ++I) ValueToAllocaMap.insert(std::make_pair(I->getValue(), AI)); - DOUT << "LICM: Promoting value: " << *V << "\n"; + DEBUG(errs() << "LICM: Promoting value: " << *V << "\n"); } } |