diff options
Diffstat (limited to 'lib/Transforms/Utils')
| -rw-r--r-- | lib/Transforms/Utils/CloneFunction.cpp | 158 | ||||
| -rw-r--r-- | lib/Transforms/Utils/InlineFunction.cpp | 17 | ||||
| -rw-r--r-- | lib/Transforms/Utils/Local.cpp | 38 | ||||
| -rw-r--r-- | lib/Transforms/Utils/LoopUnroll.cpp | 6 | ||||
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 2 | ||||
| -rw-r--r-- | lib/Transforms/Utils/SimplifyIndVar.cpp | 41 |
6 files changed, 119 insertions, 143 deletions
diff --git a/lib/Transforms/Utils/CloneFunction.cpp b/lib/Transforms/Utils/CloneFunction.cpp index 1b28c35..20052a4 100644 --- a/lib/Transforms/Utils/CloneFunction.cpp +++ b/lib/Transforms/Utils/CloneFunction.cpp @@ -23,8 +23,11 @@ #include "llvm/LLVMContext.h" #include "llvm/Metadata.h" #include "llvm/Support/CFG.h" +#include "llvm/Transforms/Utils/BasicBlockUtils.h" +#include "llvm/Transforms/Utils/Local.h" #include "llvm/Transforms/Utils/ValueMapper.h" #include "llvm/Analysis/ConstantFolding.h" +#include "llvm/Analysis/InstructionSimplify.h" #include "llvm/Analysis/DebugInfo.h" #include "llvm/ADT/SmallVector.h" #include <map> @@ -197,7 +200,6 @@ namespace { const Function *OldFunc; ValueToValueMapTy &VMap; bool ModuleLevelChanges; - SmallVectorImpl<ReturnInst*> &Returns; const char *NameSuffix; ClonedCodeInfo *CodeInfo; const TargetData *TD; @@ -205,24 +207,18 @@ namespace { PruningFunctionCloner(Function *newFunc, const Function *oldFunc, ValueToValueMapTy &valueMap, bool moduleLevelChanges, - SmallVectorImpl<ReturnInst*> &returns, const char *nameSuffix, ClonedCodeInfo *codeInfo, const TargetData *td) : NewFunc(newFunc), OldFunc(oldFunc), VMap(valueMap), ModuleLevelChanges(moduleLevelChanges), - Returns(returns), NameSuffix(nameSuffix), CodeInfo(codeInfo), TD(td) { + NameSuffix(nameSuffix), CodeInfo(codeInfo), TD(td) { } /// CloneBlock - The specified block is found to be reachable, clone it and /// anything that it can reach. void CloneBlock(const BasicBlock *BB, std::vector<const BasicBlock*> &ToClone); - - public: - /// ConstantFoldMappedInstruction - Constant fold the specified instruction, - /// mapping its operands through VMap if they are available. - Constant *ConstantFoldMappedInstruction(const Instruction *I); }; } @@ -230,7 +226,7 @@ namespace { /// anything that it can reach. void PruningFunctionCloner::CloneBlock(const BasicBlock *BB, std::vector<const BasicBlock*> &ToClone){ - TrackingVH<Value> &BBEntry = VMap[BB]; + WeakVH &BBEntry = VMap[BB]; // Have we already cloned this block? if (BBEntry) return; @@ -262,19 +258,33 @@ void PruningFunctionCloner::CloneBlock(const BasicBlock *BB, // loop doesn't include the terminator. for (BasicBlock::const_iterator II = BB->begin(), IE = --BB->end(); II != IE; ++II) { - // If this instruction constant folds, don't bother cloning the instruction, - // instead, just add the constant to the value map. - if (Constant *C = ConstantFoldMappedInstruction(II)) { - VMap[II] = C; - continue; + Instruction *NewInst = II->clone(); + + // Eagerly remap operands to the newly cloned instruction, except for PHI + // nodes for which we defer processing until we update the CFG. + if (!isa<PHINode>(NewInst)) { + RemapInstruction(NewInst, VMap, + ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges); + + // If we can simplify this instruction to some other value, simply add + // a mapping to that value rather than inserting a new instruction into + // the basic block. + if (Value *V = SimplifyInstruction(NewInst, TD)) { + // On the off-chance that this simplifies to an instruction in the old + // function, map it back into the new function. + if (Value *MappedV = VMap.lookup(V)) + V = MappedV; + + VMap[II] = V; + delete NewInst; + continue; + } } - Instruction *NewInst = II->clone(); if (II->hasName()) NewInst->setName(II->getName()+NameSuffix); - NewBB->getInstList().push_back(NewInst); VMap[II] = NewInst; // Add instruction map to value. - + NewBB->getInstList().push_back(NewInst); hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II)); if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) { if (isa<ConstantInt>(AI->getArraySize())) @@ -340,33 +350,6 @@ void PruningFunctionCloner::CloneBlock(const BasicBlock *BB, CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas && BB != &BB->getParent()->front(); } - - if (ReturnInst *RI = dyn_cast<ReturnInst>(NewBB->getTerminator())) - Returns.push_back(RI); -} - -/// ConstantFoldMappedInstruction - Constant fold the specified instruction, -/// mapping its operands through VMap if they are available. -Constant *PruningFunctionCloner:: -ConstantFoldMappedInstruction(const Instruction *I) { - SmallVector<Constant*, 8> Ops; - for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) - if (Constant *Op = dyn_cast_or_null<Constant>(MapValue(I->getOperand(i), - VMap, - ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges))) - Ops.push_back(Op); - else - return 0; // All operands not constant! - - if (const CmpInst *CI = dyn_cast<CmpInst>(I)) - return ConstantFoldCompareInstOperands(CI->getPredicate(), Ops[0], Ops[1], - TD); - - if (const LoadInst *LI = dyn_cast<LoadInst>(I)) - if (!LI->isVolatile()) - return ConstantFoldLoadFromConstPtr(Ops[0], TD); - - return ConstantFoldInstOperands(I->getOpcode(), I->getType(), Ops, TD); } /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto, @@ -393,7 +376,7 @@ void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, #endif PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges, - Returns, NameSuffix, CodeInfo, TD); + NameSuffix, CodeInfo, TD); // Clone the entry block, and anything recursively reachable from it. std::vector<const BasicBlock*> CloneWorklist; @@ -418,25 +401,19 @@ void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, // Add the new block to the new function. NewFunc->getBasicBlockList().push_back(NewBB); - - // Loop over all of the instructions in the block, fixing up operand - // references as we go. This uses VMap to do all the hard work. - // - BasicBlock::iterator I = NewBB->begin(); // Handle PHI nodes specially, as we have to remove references to dead // blocks. - if (PHINode *PN = dyn_cast<PHINode>(I)) { - // Skip over all PHI nodes, remembering them for later. - BasicBlock::const_iterator OldI = BI->begin(); - for (; (PN = dyn_cast<PHINode>(I)); ++I, ++OldI) - PHIToResolve.push_back(cast<PHINode>(OldI)); - } - - // Otherwise, remap the rest of the instructions normally. - for (; I != NewBB->end(); ++I) - RemapInstruction(I, VMap, - ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges); + for (BasicBlock::const_iterator I = BI->begin(), E = BI->end(); I != E; ++I) + if (const PHINode *PN = dyn_cast<PHINode>(I)) + PHIToResolve.push_back(PN); + else + break; + + // Finally, remap the terminator instructions, as those can't be remapped + // until all BBs are mapped. + RemapInstruction(NewBB->getTerminator(), VMap, + ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges); } // Defer PHI resolution until rest of function is resolved, PHI resolution @@ -518,31 +495,55 @@ void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, ++OldI; } } - // NOTE: We cannot eliminate single entry phi nodes here, because of - // VMap. Single entry phi nodes can have multiple VMap entries - // pointing at them. Thus, deleting one would require scanning the VMap - // to update any entries in it that would require that. This would be - // really slow. } - + + // Make a second pass over the PHINodes now that all of them have been + // remapped into the new function, simplifying the PHINode and performing any + // recursive simplifications exposed. This will transparently update the + // WeakVH in the VMap. Notably, we rely on that so that if we coalesce + // two PHINodes, the iteration over the old PHIs remains valid, and the + // mapping will just map us to the new node (which may not even be a PHI + // node). + for (unsigned Idx = 0, Size = PHIToResolve.size(); Idx != Size; ++Idx) + if (PHINode *PN = dyn_cast<PHINode>(VMap[PHIToResolve[Idx]])) + recursivelySimplifyInstruction(PN, TD); + // Now that the inlined function body has been fully constructed, go through // and zap unconditional fall-through branches. This happen all the time when // specializing code: code specialization turns conditional branches into // uncond branches, and this code folds them. - Function::iterator I = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]); + Function::iterator Begin = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]); + Function::iterator I = Begin; while (I != NewFunc->end()) { + // Check if this block has become dead during inlining or other + // simplifications. Note that the first block will appear dead, as it has + // not yet been wired up properly. + if (I != Begin && (pred_begin(I) == pred_end(I) || + I->getSinglePredecessor() == I)) { + BasicBlock *DeadBB = I++; + DeleteDeadBlock(DeadBB); + continue; + } + + // We need to simplify conditional branches and switches with a constant + // operand. We try to prune these out when cloning, but if the + // simplification required looking through PHI nodes, those are only + // available after forming the full basic block. That may leave some here, + // and we still want to prune the dead code as early as possible. + ConstantFoldTerminator(I); + BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator()); if (!BI || BI->isConditional()) { ++I; continue; } - // Note that we can't eliminate uncond branches if the destination has - // single-entry PHI nodes. Eliminating the single-entry phi nodes would - // require scanning the VMap to update any entries that point to the phi - // node. BasicBlock *Dest = BI->getSuccessor(0); - if (!Dest->getSinglePredecessor() || isa<PHINode>(Dest->begin())) { + if (!Dest->getSinglePredecessor()) { ++I; continue; } - + + // We shouldn't be able to get single-entry PHI nodes here, as instsimplify + // above should have zapped all of them.. + assert(!isa<PHINode>(Dest->begin())); + // We know all single-entry PHI nodes in the inlined function have been // removed, so we just need to splice the blocks. BI->eraseFromParent(); @@ -558,4 +559,13 @@ void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, // Do not increment I, iteratively merge all things this block branches to. } + + // Make a final pass over the basic blocks from theh old function to gather + // any return instructions which survived folding. We have to do this here + // because we can iteratively remove and merge returns above. + for (Function::iterator I = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]), + E = NewFunc->end(); + I != E; ++I) + if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) + Returns.push_back(RI); } diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp index b84de05..d2b167a 100644 --- a/lib/Transforms/Utils/InlineFunction.cpp +++ b/lib/Transforms/Utils/InlineFunction.cpp @@ -31,10 +31,12 @@ #include "llvm/Support/IRBuilder.h" using namespace llvm; -bool llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI, bool InsertLifetime) { +bool llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI, + bool InsertLifetime) { return InlineFunction(CallSite(CI), IFI, InsertLifetime); } -bool llvm::InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI, bool InsertLifetime) { +bool llvm::InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI, + bool InsertLifetime) { return InlineFunction(CallSite(II), IFI, InsertLifetime); } @@ -434,8 +436,8 @@ static bool hasLifetimeMarkers(AllocaInst *AI) { return false; } -/// updateInlinedAtInfo - Helper function used by fixupLineNumbers to recursively -/// update InlinedAtEntry of a DebugLoc. +/// updateInlinedAtInfo - Helper function used by fixupLineNumbers to +/// recursively update InlinedAtEntry of a DebugLoc. static DebugLoc updateInlinedAtInfo(const DebugLoc &DL, const DebugLoc &InlinedAtDL, LLVMContext &Ctx) { @@ -445,7 +447,7 @@ static DebugLoc updateInlinedAtInfo(const DebugLoc &DL, return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(Ctx), NewInlinedAtDL.getAsMDNode(Ctx)); } - + return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(Ctx), InlinedAtDL.getAsMDNode(Ctx)); } @@ -453,7 +455,7 @@ static DebugLoc updateInlinedAtInfo(const DebugLoc &DL, /// fixupLineNumbers - Update inlined instructions' line numbers to /// to encode location where these instructions are inlined. static void fixupLineNumbers(Function *Fn, Function::iterator FI, - Instruction *TheCall) { + Instruction *TheCall) { DebugLoc TheCallDL = TheCall->getDebugLoc(); if (TheCallDL.isUnknown()) return; @@ -484,7 +486,8 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI, /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now /// exists in the instruction stream. Similarly this will inline a recursive /// function by one level. -bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI, bool InsertLifetime) { +bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI, + bool InsertLifetime) { Instruction *TheCall = CS.getInstruction(); assert(TheCall->getParent() && TheCall->getParent()->getParent() && "Instruction not in function!"); diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp index 5f895eb..d1c4d59 100644 --- a/lib/Transforms/Utils/Local.cpp +++ b/lib/Transforms/Utils/Local.cpp @@ -355,22 +355,27 @@ bool llvm::RecursivelyDeleteDeadPHINode(PHINode *PN) { /// instructions in other blocks as well in this block. bool llvm::SimplifyInstructionsInBlock(BasicBlock *BB, const TargetData *TD) { bool MadeChange = false; - for (BasicBlock::iterator BI = BB->begin(), E = BB->end(); BI != E; ) { + +#ifndef NDEBUG + // In debug builds, ensure that the terminator of the block is never replaced + // or deleted by these simplifications. The idea of simplification is that it + // cannot introduce new instructions, and there is no way to replace the + // terminator of a block without introducing a new instruction. + AssertingVH<Instruction> TerminatorVH(--BB->end()); +#endif + + for (BasicBlock::iterator BI = BB->begin(), E = --BB->end(); BI != E; ) { + assert(!BI->isTerminator()); Instruction *Inst = BI++; - - if (Value *V = SimplifyInstruction(Inst, TD)) { - WeakVH BIHandle(BI); - ReplaceAndSimplifyAllUses(Inst, V, TD); + + WeakVH BIHandle(BI); + if (recursivelySimplifyInstruction(Inst, TD)) { MadeChange = true; if (BIHandle != BI) BI = BB->begin(); continue; } - if (Inst->isTerminator()) - break; - - WeakVH BIHandle(BI); MadeChange |= RecursivelyDeleteTriviallyDeadInstructions(Inst); if (BIHandle != BI) BI = BB->begin(); @@ -408,17 +413,11 @@ void llvm::RemovePredecessorAndSimplify(BasicBlock *BB, BasicBlock *Pred, WeakVH PhiIt = &BB->front(); while (PHINode *PN = dyn_cast<PHINode>(PhiIt)) { PhiIt = &*++BasicBlock::iterator(cast<Instruction>(PhiIt)); + Value *OldPhiIt = PhiIt; - Value *PNV = SimplifyInstruction(PN, TD); - if (PNV == 0) continue; + if (!recursivelySimplifyInstruction(PN, TD)) + continue; - // If we're able to simplify the phi to a single value, substitute the new - // value into all of its uses. - assert(PNV != PN && "SimplifyInstruction broken!"); - - Value *OldPhiIt = PhiIt; - ReplaceAndSimplifyAllUses(PN, PNV, TD); - // If recursive simplification ended up deleting the next PHI node we would // iterate to, then our iterator is invalid, restart scanning from the top // of the block. @@ -763,9 +762,8 @@ unsigned llvm::getOrEnforceKnownAlignment(Value *V, unsigned PrefAlign, assert(V->getType()->isPointerTy() && "getOrEnforceKnownAlignment expects a pointer!"); unsigned BitWidth = TD ? TD->getPointerSizeInBits() : 64; - APInt Mask = APInt::getAllOnesValue(BitWidth); APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); - ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD); + ComputeMaskedBits(V, KnownZero, KnownOne, TD); unsigned TrailZ = KnownZero.countTrailingOnes(); // Avoid trouble with rediculously large TrailZ values, such as diff --git a/lib/Transforms/Utils/LoopUnroll.cpp b/lib/Transforms/Utils/LoopUnroll.cpp index 512b689..e15497a 100644 --- a/lib/Transforms/Utils/LoopUnroll.cpp +++ b/lib/Transforms/Utils/LoopUnroll.cpp @@ -149,6 +149,12 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount, return false; } + // Loops with indirectbr cannot be cloned. + if (!L->isSafeToClone()) { + DEBUG(dbgs() << " Can't unroll; Loop body cannot be cloned.\n"); + return false; + } + BasicBlock *Header = L->getHeader(); BranchInst *BI = dyn_cast<BranchInst>(LatchBlock->getTerminator()); diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index d53a46e..66dd2c9 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -2562,7 +2562,7 @@ static bool EliminateDeadSwitchCases(SwitchInst *SI) { Value *Cond = SI->getCondition(); unsigned Bits = cast<IntegerType>(Cond->getType())->getBitWidth(); APInt KnownZero(Bits, 0), KnownOne(Bits, 0); - ComputeMaskedBits(Cond, APInt::getAllOnesValue(Bits), KnownZero, KnownOne); + ComputeMaskedBits(Cond, KnownZero, KnownOne); // Gather dead cases. SmallVector<ConstantInt*, 8> DeadCases; diff --git a/lib/Transforms/Utils/SimplifyIndVar.cpp b/lib/Transforms/Utils/SimplifyIndVar.cpp index e00565d..4030bef 100644 --- a/lib/Transforms/Utils/SimplifyIndVar.cpp +++ b/lib/Transforms/Utils/SimplifyIndVar.cpp @@ -46,7 +46,6 @@ namespace { LoopInfo *LI; DominatorTree *DT; ScalarEvolution *SE; - IVUsers *IU; // NULL for DisableIVRewrite const TargetData *TD; // May be NULL SmallVectorImpl<WeakVH> &DeadInsts; @@ -59,7 +58,6 @@ namespace { L(Loop), LI(LPM->getAnalysisIfAvailable<LoopInfo>()), SE(SE), - IU(IVU), TD(LPM->getAnalysisIfAvailable<TargetData>()), DeadInsts(Dead), Changed(false) { @@ -229,13 +227,6 @@ void SimplifyIndvar::eliminateIVRemainder(BinaryOperator *Rem, Rem->replaceAllUsesWith(Sel); } - // Inform IVUsers about the new users. - if (IU) { - if (Instruction *I = dyn_cast<Instruction>(Rem->getOperand(0))) { - SmallPtrSet<Loop*, 16> SimplifiedLoopNests; - IU->AddUsersIfInteresting(I, SimplifiedLoopNests); - } - } DEBUG(dbgs() << "INDVARS: Simplified rem: " << *Rem << '\n'); ++NumElimRem; Changed = true; @@ -401,36 +392,4 @@ bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, LPPassManager *LPM, return Changed; } -/// simplifyIVUsers - Perform simplification on instructions recorded by the -/// IVUsers pass. -/// -/// This is the old approach to IV simplification to be replaced by -/// SimplifyLoopIVs. -bool simplifyIVUsers(IVUsers *IU, ScalarEvolution *SE, LPPassManager *LPM, - SmallVectorImpl<WeakVH> &Dead) { - SimplifyIndvar SIV(IU->getLoop(), SE, LPM, Dead); - - // Each round of simplification involves a round of eliminating operations - // followed by a round of widening IVs. A single IVUsers worklist is used - // across all rounds. The inner loop advances the user. If widening exposes - // more uses, then another pass through the outer loop is triggered. - for (IVUsers::iterator I = IU->begin(); I != IU->end(); ++I) { - Instruction *UseInst = I->getUser(); - Value *IVOperand = I->getOperandValToReplace(); - - if (ICmpInst *ICmp = dyn_cast<ICmpInst>(UseInst)) { - SIV.eliminateIVComparison(ICmp, IVOperand); - continue; - } - if (BinaryOperator *Rem = dyn_cast<BinaryOperator>(UseInst)) { - bool IsSigned = Rem->getOpcode() == Instruction::SRem; - if (IsSigned || Rem->getOpcode() == Instruction::URem) { - SIV.eliminateIVRemainder(Rem, IVOperand, IsSigned); - continue; - } - } - } - return SIV.hasChanged(); -} - } // namespace llvm |