X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FInstCombine%2FInstCombinePHI.cpp;h=f1aa98b5e3595ad0df6ddb342e31872b382519ce;hb=e78257c891d8a6148703cb74655640d175e3f570;hp=297a18c40a97968b59b6da9c83d32ca26156df6f;hpb=c8cb8ef9c2d5e354db661022d707a19b3533c00e;p=oota-llvm.git diff --git a/lib/Transforms/InstCombine/InstCombinePHI.cpp b/lib/Transforms/InstCombine/InstCombinePHI.cpp index 297a18c40a9..f1aa98b5e35 100644 --- a/lib/Transforms/InstCombine/InstCombinePHI.cpp +++ b/lib/Transforms/InstCombine/InstCombinePHI.cpp @@ -11,26 +11,27 @@ // //===----------------------------------------------------------------------===// -#include "InstCombine.h" -#include "llvm/Analysis/InstructionSimplify.h" -#include "llvm/Target/TargetData.h" -#include "llvm/ADT/SmallPtrSet.h" +#include "InstCombineInternal.h" #include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/Analysis/InstructionSimplify.h" +#include "llvm/Transforms/Utils/Local.h" using namespace llvm; -/// FoldPHIArgBinOpIntoPHI - If we have something like phi [add (a,b), add(a,c)] -/// and if a/b/c and the add's all have a single use, turn this into a phi -/// and a single binop. +#define DEBUG_TYPE "instcombine" + +/// If we have something like phi [add (a,b), add(a,c)] and if a/b/c and the +/// adds all have a single use, turn this into a phi and a single binop. Instruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) { Instruction *FirstInst = cast(PN.getIncomingValue(0)); assert(isa(FirstInst) || isa(FirstInst)); unsigned Opc = FirstInst->getOpcode(); Value *LHSVal = FirstInst->getOperand(0); Value *RHSVal = FirstInst->getOperand(1); - - const Type *LHSType = LHSVal->getType(); - const Type *RHSType = RHSVal->getType(); - + + Type *LHSType = LHSVal->getType(); + Type *RHSType = RHSVal->getType(); + bool isNUW = false, isNSW = false, isExact = false; if (OverflowingBinaryOperator *BO = dyn_cast(FirstInst)) { @@ -39,7 +40,7 @@ Instruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) { } else if (PossiblyExactOperator *PEO = dyn_cast(FirstInst)) isExact = PEO->isExact(); - + // Scan to see if all operands are the same opcode, and all have one use. for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) { Instruction *I = dyn_cast(PN.getIncomingValue(i)); @@ -48,23 +49,23 @@ Instruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) { // types. I->getOperand(0)->getType() != LHSType || I->getOperand(1)->getType() != RHSType) - return 0; + return nullptr; // If they are CmpInst instructions, check their predicates if (CmpInst *CI = dyn_cast(I)) if (CI->getPredicate() != cast(FirstInst)->getPredicate()) - return 0; - + return nullptr; + if (isNUW) isNUW = cast(I)->hasNoUnsignedWrap(); if (isNSW) isNSW = cast(I)->hasNoSignedWrap(); if (isExact) isExact = cast(I)->isExact(); - + // Keep track of which operand needs a phi node. - if (I->getOperand(0) != LHSVal) LHSVal = 0; - if (I->getOperand(1) != RHSVal) RHSVal = 0; + if (I->getOperand(0) != LHSVal) LHSVal = nullptr; + if (I->getOperand(1) != RHSVal) RHSVal = nullptr; } // If both LHS and RHS would need a PHI, don't do this transformation, @@ -72,31 +73,29 @@ Instruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) { // which leads to higher register pressure. This is especially // bad when the PHIs are in the header of a loop. if (!LHSVal && !RHSVal) - return 0; - + return nullptr; + // Otherwise, this is safe to transform! - + Value *InLHS = FirstInst->getOperand(0); Value *InRHS = FirstInst->getOperand(1); - PHINode *NewLHS = 0, *NewRHS = 0; - if (LHSVal == 0) { - NewLHS = PHINode::Create(LHSType, + PHINode *NewLHS = nullptr, *NewRHS = nullptr; + if (!LHSVal) { + NewLHS = PHINode::Create(LHSType, PN.getNumIncomingValues(), FirstInst->getOperand(0)->getName() + ".pn"); - NewLHS->reserveOperandSpace(PN.getNumOperands()/2); NewLHS->addIncoming(InLHS, PN.getIncomingBlock(0)); InsertNewInstBefore(NewLHS, PN); LHSVal = NewLHS; } - - if (RHSVal == 0) { - NewRHS = PHINode::Create(RHSType, + + if (!RHSVal) { + NewRHS = PHINode::Create(RHSType, PN.getNumIncomingValues(), FirstInst->getOperand(1)->getName() + ".pn"); - NewRHS->reserveOperandSpace(PN.getNumOperands()/2); NewRHS->addIncoming(InRHS, PN.getIncomingBlock(0)); InsertNewInstBefore(NewRHS, PN); RHSVal = NewRHS; } - + // Add all operands to the new PHIs. if (NewLHS || NewRHS) { for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { @@ -111,24 +110,28 @@ Instruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) { } } } - - if (CmpInst *CIOp = dyn_cast(FirstInst)) - return CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(), - LHSVal, RHSVal); - + + if (CmpInst *CIOp = dyn_cast(FirstInst)) { + CmpInst *NewCI = CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(), + LHSVal, RHSVal); + NewCI->setDebugLoc(FirstInst->getDebugLoc()); + return NewCI; + } + BinaryOperator *BinOp = cast(FirstInst); BinaryOperator *NewBinOp = BinaryOperator::Create(BinOp->getOpcode(), LHSVal, RHSVal); if (isNUW) NewBinOp->setHasNoUnsignedWrap(); if (isNSW) NewBinOp->setHasNoSignedWrap(); if (isExact) NewBinOp->setIsExact(); + NewBinOp->setDebugLoc(FirstInst->getDebugLoc()); return NewBinOp; } Instruction *InstCombiner::FoldPHIArgGEPIntoPHI(PHINode &PN) { GetElementPtrInst *FirstInst =cast(PN.getIncomingValue(0)); - - SmallVector FixedOperands(FirstInst->op_begin(), + + SmallVector FixedOperands(FirstInst->op_begin(), FirstInst->op_end()); // This is true if all GEP bases are allocas and if all indices into them are // constants. @@ -138,29 +141,29 @@ Instruction *InstCombiner::FoldPHIArgGEPIntoPHI(PHINode &PN) { // more than one phi, which leads to higher register pressure. This is // especially bad when the PHIs are in the header of a loop. bool NeededPhi = false; - + bool AllInBounds = true; - + // Scan to see if all operands are the same opcode, and all have one use. for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) { GetElementPtrInst *GEP= dyn_cast(PN.getIncomingValue(i)); if (!GEP || !GEP->hasOneUse() || GEP->getType() != FirstInst->getType() || GEP->getNumOperands() != FirstInst->getNumOperands()) - return 0; + return nullptr; AllInBounds &= GEP->isInBounds(); - + // Keep track of whether or not all GEPs are of alloca pointers. if (AllBasePointersAreAllocas && (!isa(GEP->getOperand(0)) || !GEP->hasAllConstantIndices())) AllBasePointersAreAllocas = false; - + // Compare the operand lists. for (unsigned op = 0, e = FirstInst->getNumOperands(); op != e; ++op) { if (FirstInst->getOperand(op) == GEP->getOperand(op)) continue; - + // Don't merge two GEPs when two operands differ (introducing phi nodes) // if one of the PHIs has a constant for the index. The index may be // substantially cheaper to compute for the constants, so making it a @@ -168,23 +171,23 @@ Instruction *InstCombiner::FoldPHIArgGEPIntoPHI(PHINode &PN) { // for struct indices, which must always be constant. if (isa(FirstInst->getOperand(op)) || isa(GEP->getOperand(op))) - return 0; - + return nullptr; + if (FirstInst->getOperand(op)->getType() !=GEP->getOperand(op)->getType()) - return 0; + return nullptr; // If we already needed a PHI for an earlier operand, and another operand // also requires a PHI, we'd be introducing more PHIs than we're // eliminating, which increases register pressure on entry to the PHI's // block. if (NeededPhi) - return 0; + return nullptr; - FixedOperands[op] = 0; // Needs a PHI. + FixedOperands[op] = nullptr; // Needs a PHI. NeededPhi = true; } } - + // If all of the base pointers of the PHI'd GEPs are from allocas, don't // bother doing this transformation. At best, this will just save a bit of // offset calculation, but all the predecessors will have to materialize the @@ -192,71 +195,68 @@ Instruction *InstCombiner::FoldPHIArgGEPIntoPHI(PHINode &PN) { // load up into the predecessors so that we have a load of a gep of an alloca, // which can usually all be folded into the load. if (AllBasePointersAreAllocas) - return 0; - + return nullptr; + // Otherwise, this is safe to transform. Insert PHI nodes for each operand // that is variable. SmallVector OperandPhis(FixedOperands.size()); - + bool HasAnyPHIs = false; for (unsigned i = 0, e = FixedOperands.size(); i != e; ++i) { if (FixedOperands[i]) continue; // operand doesn't need a phi. Value *FirstOp = FirstInst->getOperand(i); - PHINode *NewPN = PHINode::Create(FirstOp->getType(), + PHINode *NewPN = PHINode::Create(FirstOp->getType(), e, FirstOp->getName()+".pn"); InsertNewInstBefore(NewPN, PN); - - NewPN->reserveOperandSpace(e); + NewPN->addIncoming(FirstOp, PN.getIncomingBlock(0)); OperandPhis[i] = NewPN; FixedOperands[i] = NewPN; HasAnyPHIs = true; } - + // Add all operands to the new PHIs. if (HasAnyPHIs) { for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { GetElementPtrInst *InGEP =cast(PN.getIncomingValue(i)); BasicBlock *InBB = PN.getIncomingBlock(i); - + for (unsigned op = 0, e = OperandPhis.size(); op != e; ++op) if (PHINode *OpPhi = OperandPhis[op]) OpPhi->addIncoming(InGEP->getOperand(op), InBB); } } - + Value *Base = FixedOperands[0]; - GetElementPtrInst *NewGEP = - GetElementPtrInst::Create(Base, FixedOperands.begin()+1, - FixedOperands.end()); + GetElementPtrInst *NewGEP = + GetElementPtrInst::Create(FirstInst->getSourceElementType(), Base, + makeArrayRef(FixedOperands).slice(1)); if (AllInBounds) NewGEP->setIsInBounds(); + NewGEP->setDebugLoc(FirstInst->getDebugLoc()); return NewGEP; } -/// isSafeAndProfitableToSinkLoad - Return true if we know that it is safe to -/// sink the load out of the block that defines it. This means that it must be -/// obvious the value of the load is not changed from the point of the load to -/// the end of the block it is in. +/// Return true if we know that it is safe to sink the load out of the block +/// that defines it. This means that it must be obvious the value of the load is +/// not changed from the point of the load to the end of the block it is in. /// -/// Finally, it is safe, but not profitable, to sink a load targetting a +/// Finally, it is safe, but not profitable, to sink a load targeting a /// non-address-taken alloca. Doing so will cause us to not promote the alloca /// to a register. static bool isSafeAndProfitableToSinkLoad(LoadInst *L) { - BasicBlock::iterator BBI = L, E = L->getParent()->end(); - + BasicBlock::iterator BBI = L->getIterator(), E = L->getParent()->end(); + for (++BBI; BBI != E; ++BBI) if (BBI->mayWriteToMemory()) return false; - + // Check for non-address taken alloca. If not address-taken already, it isn't // profitable to do this xform. if (AllocaInst *AI = dyn_cast(L->getOperand(0))) { bool isAddressTaken = false; - for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end(); - UI != E; ++UI) { - User *U = *UI; + for (User *U : AI->users()) { if (isa(U)) continue; if (StoreInst *SI = dyn_cast(U)) { // If storing TO the alloca, then the address isn't taken. @@ -265,11 +265,11 @@ static bool isSafeAndProfitableToSinkLoad(LoadInst *L) { isAddressTaken = true; break; } - + if (!isAddressTaken && AI->isStaticAlloca()) return false; } - + // If this load is a load from a GEP with a constant offset from an alloca, // then we don't want to sink it. In its present form, it will be // load [constant stack offset]. Sinking it will cause us to have to @@ -279,13 +279,18 @@ static bool isSafeAndProfitableToSinkLoad(LoadInst *L) { if (AllocaInst *AI = dyn_cast(GEP->getOperand(0))) if (AI->isStaticAlloca() && GEP->hasAllConstantIndices()) return false; - + return true; } Instruction *InstCombiner::FoldPHIArgLoadIntoPHI(PHINode &PN) { LoadInst *FirstLI = cast(PN.getIncomingValue(0)); - + + // FIXME: This is overconservative; this transform is allowed in some cases + // for atomic operations. + if (FirstLI->isAtomic()) + return nullptr; + // When processing loads, we need to propagate two bits of information to the // sunk load: whether it is volatile, and what its alignment is. We currently // don't sink loads when some have their alignment specified and some don't. @@ -294,108 +299,203 @@ Instruction *InstCombiner::FoldPHIArgLoadIntoPHI(PHINode &PN) { bool isVolatile = FirstLI->isVolatile(); unsigned LoadAlignment = FirstLI->getAlignment(); unsigned LoadAddrSpace = FirstLI->getPointerAddressSpace(); - + // We can't sink the load if the loaded value could be modified between the // load and the PHI. if (FirstLI->getParent() != PN.getIncomingBlock(0) || !isSafeAndProfitableToSinkLoad(FirstLI)) - return 0; - + return nullptr; + // If the PHI is of volatile loads and the load block has multiple // successors, sinking it would remove a load of the volatile value from // the path through the other successor. - if (isVolatile && + if (isVolatile && FirstLI->getParent()->getTerminator()->getNumSuccessors() != 1) - return 0; - + return nullptr; + // Check to see if all arguments are the same operation. for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { LoadInst *LI = dyn_cast(PN.getIncomingValue(i)); if (!LI || !LI->hasOneUse()) - return 0; - - // We can't sink the load if the loaded value could be modified between + return nullptr; + + // We can't sink the load if the loaded value could be modified between // the load and the PHI. if (LI->isVolatile() != isVolatile || LI->getParent() != PN.getIncomingBlock(i) || LI->getPointerAddressSpace() != LoadAddrSpace || !isSafeAndProfitableToSinkLoad(LI)) - return 0; - + return nullptr; + // If some of the loads have an alignment specified but not all of them, // we can't do the transformation. if ((LoadAlignment != 0) != (LI->getAlignment() != 0)) - return 0; - + return nullptr; + LoadAlignment = std::min(LoadAlignment, LI->getAlignment()); - + // If the PHI is of volatile loads and the load block has multiple // successors, sinking it would remove a load of the volatile value from // the path through the other successor. if (isVolatile && LI->getParent()->getTerminator()->getNumSuccessors() != 1) - return 0; + return nullptr; } - + // Okay, they are all the same operation. Create a new PHI node of the // correct type, and PHI together all of the LHS's of the instructions. PHINode *NewPN = PHINode::Create(FirstLI->getOperand(0)->getType(), + PN.getNumIncomingValues(), PN.getName()+".in"); - NewPN->reserveOperandSpace(PN.getNumOperands()/2); - + Value *InVal = FirstLI->getOperand(0); NewPN->addIncoming(InVal, PN.getIncomingBlock(0)); - - // Add all operands to the new PHI. + LoadInst *NewLI = new LoadInst(NewPN, "", isVolatile, LoadAlignment); + + unsigned KnownIDs[] = { + LLVMContext::MD_tbaa, + LLVMContext::MD_range, + LLVMContext::MD_invariant_load, + LLVMContext::MD_alias_scope, + LLVMContext::MD_noalias, + LLVMContext::MD_nonnull, + LLVMContext::MD_align, + LLVMContext::MD_dereferenceable, + LLVMContext::MD_dereferenceable_or_null, + }; + + for (unsigned ID : KnownIDs) + NewLI->setMetadata(ID, FirstLI->getMetadata(ID)); + + // Add all operands to the new PHI and combine TBAA metadata. for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { - Value *NewInVal = cast(PN.getIncomingValue(i))->getOperand(0); + LoadInst *LI = cast(PN.getIncomingValue(i)); + combineMetadata(NewLI, LI, KnownIDs); + Value *NewInVal = LI->getOperand(0); if (NewInVal != InVal) - InVal = 0; + InVal = nullptr; NewPN->addIncoming(NewInVal, PN.getIncomingBlock(i)); } - - Value *PhiVal; + if (InVal) { // The new PHI unions all of the same values together. This is really // common, so we handle it intelligently here for compile-time speed. - PhiVal = InVal; + NewLI->setOperand(0, InVal); delete NewPN; } else { InsertNewInstBefore(NewPN, PN); - PhiVal = NewPN; } - + // If this was a volatile load that we are merging, make sure to loop through // and mark all the input loads as non-volatile. If we don't do this, we will // insert a new volatile load and the old ones will not be deletable. if (isVolatile) - for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) - cast(PN.getIncomingValue(i))->setVolatile(false); - - return new LoadInst(PhiVal, "", isVolatile, LoadAlignment); + for (Value *IncValue : PN.incoming_values()) + cast(IncValue)->setVolatile(false); + + NewLI->setDebugLoc(FirstLI->getDebugLoc()); + return NewLI; } +/// TODO: This function could handle other cast types, but then it might +/// require special-casing a cast from the 'i1' type. See the comment in +/// FoldPHIArgOpIntoPHI() about pessimizing illegal integer types. +Instruction *InstCombiner::FoldPHIArgZextsIntoPHI(PHINode &Phi) { + // We cannot create a new instruction after the PHI if the terminator is an + // EHPad because there is no valid insertion point. + if (TerminatorInst *TI = Phi.getParent()->getTerminator()) + if (TI->isEHPad()) + return nullptr; + + // Early exit for the common case of a phi with two operands. These are + // handled elsewhere. See the comment below where we check the count of zexts + // and constants for more details. + unsigned NumIncomingValues = Phi.getNumIncomingValues(); + if (NumIncomingValues < 3) + return nullptr; + + // Find the narrower type specified by the first zext. + Type *NarrowType = nullptr; + for (Value *V : Phi.incoming_values()) { + if (auto *Zext = dyn_cast(V)) { + NarrowType = Zext->getSrcTy(); + break; + } + } + if (!NarrowType) + return nullptr; + + // Walk the phi operands checking that we only have zexts or constants that + // we can shrink for free. Store the new operands for the new phi. + SmallVector NewIncoming; + unsigned NumZexts = 0; + unsigned NumConsts = 0; + for (Value *V : Phi.incoming_values()) { + if (auto *Zext = dyn_cast(V)) { + // All zexts must be identical and have one use. + if (Zext->getSrcTy() != NarrowType || !Zext->hasOneUse()) + return nullptr; + NewIncoming.push_back(Zext->getOperand(0)); + NumZexts++; + } else if (auto *C = dyn_cast(V)) { + // Make sure that constants can fit in the new type. + Constant *Trunc = ConstantExpr::getTrunc(C, NarrowType); + if (ConstantExpr::getZExt(Trunc, C->getType()) != C) + return nullptr; + NewIncoming.push_back(Trunc); + NumConsts++; + } else { + // If it's not a cast or a constant, bail out. + return nullptr; + } + } + // The more common cases of a phi with no constant operands or just one + // variable operand are handled by FoldPHIArgOpIntoPHI() and FoldOpIntoPhi() + // respectively. FoldOpIntoPhi() wants to do the opposite transform that is + // performed here. It tries to replicate a cast in the phi operand's basic + // block to expose other folding opportunities. Thus, InstCombine will + // infinite loop without this check. + if (NumConsts == 0 || NumZexts < 2) + return nullptr; + + // All incoming values are zexts or constants that are safe to truncate. + // Create a new phi node of the narrow type, phi together all of the new + // operands, and zext the result back to the original type. + PHINode *NewPhi = PHINode::Create(NarrowType, NumIncomingValues, + Phi.getName() + ".shrunk"); + for (unsigned i = 0; i != NumIncomingValues; ++i) + NewPhi->addIncoming(NewIncoming[i], Phi.getIncomingBlock(i)); + + InsertNewInstBefore(NewPhi, Phi); + return CastInst::CreateZExtOrBitCast(NewPhi, Phi.getType()); +} -/// FoldPHIArgOpIntoPHI - If all operands to a PHI node are the same "unary" -/// operator and they all are only used by the PHI, PHI together their -/// inputs, and do the operation once, to the result of the PHI. +/// If all operands to a PHI node are the same "unary" operator and they all are +/// only used by the PHI, PHI together their inputs, and do the operation once, +/// to the result of the PHI. Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) { + // We cannot create a new instruction after the PHI if the terminator is an + // EHPad because there is no valid insertion point. + if (TerminatorInst *TI = PN.getParent()->getTerminator()) + if (TI->isEHPad()) + return nullptr; + Instruction *FirstInst = cast(PN.getIncomingValue(0)); if (isa(FirstInst)) return FoldPHIArgGEPIntoPHI(PN); if (isa(FirstInst)) return FoldPHIArgLoadIntoPHI(PN); - + // Scan the instruction, looking for input operations that can be folded away. // If all input operands to the phi are the same instruction (e.g. a cast from // the same type or "+42") we can pull the operation through the PHI, reducing // code size and simplifying code. - Constant *ConstantOp = 0; - const Type *CastSrcTy = 0; + Constant *ConstantOp = nullptr; + Type *CastSrcTy = nullptr; bool isNUW = false, isNSW = false, isExact = false; - + if (isa(FirstInst)) { CastSrcTy = FirstInst->getOperand(0)->getType(); @@ -403,15 +503,15 @@ Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) { // the code by turning an i32 into an i1293. if (PN.getType()->isIntegerTy() && CastSrcTy->isIntegerTy()) { if (!ShouldChangeType(PN.getType(), CastSrcTy)) - return 0; + return nullptr; } } else if (isa(FirstInst) || isa(FirstInst)) { - // Can fold binop, compare or shift here if the RHS is a constant, + // Can fold binop, compare or shift here if the RHS is a constant, // otherwise call FoldPHIArgBinOpIntoPHI. ConstantOp = dyn_cast(FirstInst->getOperand(1)); - if (ConstantOp == 0) + if (!ConstantOp) return FoldPHIArgBinOpIntoPHI(PN); - + if (OverflowingBinaryOperator *BO = dyn_cast(FirstInst)) { isNUW = BO->hasNoUnsignedWrap(); @@ -420,21 +520,21 @@ Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) { dyn_cast(FirstInst)) isExact = PEO->isExact(); } else { - return 0; // Cannot fold this operation. + return nullptr; // Cannot fold this operation. } // Check to see if all arguments are the same operation. for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { Instruction *I = dyn_cast(PN.getIncomingValue(i)); - if (I == 0 || !I->hasOneUse() || !I->isSameOperationAs(FirstInst)) - return 0; + if (!I || !I->hasOneUse() || !I->isSameOperationAs(FirstInst)) + return nullptr; if (CastSrcTy) { if (I->getOperand(0)->getType() != CastSrcTy) - return 0; // Cast operation must match. + return nullptr; // Cast operation must match. } else if (I->getOperand(1) != ConstantOp) { - return 0; + return nullptr; } - + if (isNUW) isNUW = cast(I)->hasNoUnsignedWrap(); if (isNSW) @@ -446,8 +546,8 @@ Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) { // Okay, they are all the same operation. Create a new PHI node of the // correct type, and PHI together all of the LHS's of the instructions. PHINode *NewPN = PHINode::Create(FirstInst->getOperand(0)->getType(), + PN.getNumIncomingValues(), PN.getName()+".in"); - NewPN->reserveOperandSpace(PN.getNumOperands()/2); Value *InVal = FirstInst->getOperand(0); NewPN->addIncoming(InVal, PN.getIncomingBlock(0)); @@ -456,7 +556,7 @@ Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) { for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { Value *NewInVal = cast(PN.getIncomingValue(i))->getOperand(0); if (NewInVal != InVal) - InVal = 0; + InVal = nullptr; NewPN->addIncoming(NewInVal, PN.getIncomingBlock(i)); } @@ -472,67 +572,72 @@ Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) { } // Insert and return the new operation. - if (CastInst *FirstCI = dyn_cast(FirstInst)) - return CastInst::Create(FirstCI->getOpcode(), PhiVal, PN.getType()); - + if (CastInst *FirstCI = dyn_cast(FirstInst)) { + CastInst *NewCI = CastInst::Create(FirstCI->getOpcode(), PhiVal, + PN.getType()); + NewCI->setDebugLoc(FirstInst->getDebugLoc()); + return NewCI; + } + if (BinaryOperator *BinOp = dyn_cast(FirstInst)) { BinOp = BinaryOperator::Create(BinOp->getOpcode(), PhiVal, ConstantOp); if (isNUW) BinOp->setHasNoUnsignedWrap(); if (isNSW) BinOp->setHasNoSignedWrap(); if (isExact) BinOp->setIsExact(); + BinOp->setDebugLoc(FirstInst->getDebugLoc()); return BinOp; } - + CmpInst *CIOp = cast(FirstInst); - return CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(), - PhiVal, ConstantOp); + CmpInst *NewCI = CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(), + PhiVal, ConstantOp); + NewCI->setDebugLoc(FirstInst->getDebugLoc()); + return NewCI; } -/// DeadPHICycle - Return true if this PHI node is only used by a PHI node cycle -/// that is dead. +/// Return true if this PHI node is only used by a PHI node cycle that is dead. static bool DeadPHICycle(PHINode *PN, - SmallPtrSet &PotentiallyDeadPHIs) { + SmallPtrSetImpl &PotentiallyDeadPHIs) { if (PN->use_empty()) return true; if (!PN->hasOneUse()) return false; // Remember this node, and if we find the cycle, return. - if (!PotentiallyDeadPHIs.insert(PN)) + if (!PotentiallyDeadPHIs.insert(PN).second) return true; - + // Don't scan crazily complex things. if (PotentiallyDeadPHIs.size() == 16) return false; - if (PHINode *PU = dyn_cast(PN->use_back())) + if (PHINode *PU = dyn_cast(PN->user_back())) return DeadPHICycle(PU, PotentiallyDeadPHIs); return false; } -/// PHIsEqualValue - Return true if this phi node is always equal to -/// NonPhiInVal. This happens with mutually cyclic phi nodes like: +/// Return true if this phi node is always equal to NonPhiInVal. +/// This happens with mutually cyclic phi nodes like: /// z = some value; x = phi (y, z); y = phi (x, z) -static bool PHIsEqualValue(PHINode *PN, Value *NonPhiInVal, - SmallPtrSet &ValueEqualPHIs) { +static bool PHIsEqualValue(PHINode *PN, Value *NonPhiInVal, + SmallPtrSetImpl &ValueEqualPHIs) { // See if we already saw this PHI node. - if (!ValueEqualPHIs.insert(PN)) + if (!ValueEqualPHIs.insert(PN).second) return true; - + // Don't scan crazily complex things. if (ValueEqualPHIs.size() == 16) return false; - + // Scan the operands to see if they are either phi nodes or are equal to // the value. - for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { - Value *Op = PN->getIncomingValue(i); + for (Value *Op : PN->incoming_values()) { if (PHINode *OpPN = dyn_cast(Op)) { if (!PHIsEqualValue(OpPN, NonPhiInVal, ValueEqualPHIs)) return false; } else if (Op != NonPhiInVal) return false; } - + return true; } @@ -542,10 +647,10 @@ struct PHIUsageRecord { unsigned PHIId; // The ID # of the PHI (something determinstic to sort on) unsigned Shift; // The amount shifted. Instruction *Inst; // The trunc instruction. - + PHIUsageRecord(unsigned pn, unsigned Sh, Instruction *User) : PHIId(pn), Shift(Sh), Inst(User) {} - + bool operator<(const PHIUsageRecord &RHS) const { if (PHIId < RHS.PHIId) return true; if (PHIId > RHS.PHIId) return false; @@ -555,15 +660,15 @@ struct PHIUsageRecord { RHS.Inst->getType()->getPrimitiveSizeInBits(); } }; - + struct LoweredPHIRecord { PHINode *PN; // The PHI that was lowered. unsigned Shift; // The amount shifted. unsigned Width; // The width extracted. - - LoweredPHIRecord(PHINode *pn, unsigned Sh, const Type *Ty) + + LoweredPHIRecord(PHINode *pn, unsigned Sh, Type *Ty) : PN(pn), Shift(Sh), Width(Ty->getPrimitiveSizeInBits()) {} - + // Ctor form used by DenseMap. LoweredPHIRecord(PHINode *pn, unsigned Sh) : PN(pn), Shift(Sh), Width(0) {} @@ -574,10 +679,10 @@ namespace llvm { template<> struct DenseMapInfo { static inline LoweredPHIRecord getEmptyKey() { - return LoweredPHIRecord(0, 0); + return LoweredPHIRecord(nullptr, 0); } static inline LoweredPHIRecord getTombstoneKey() { - return LoweredPHIRecord(0, 1); + return LoweredPHIRecord(nullptr, 1); } static unsigned getHashValue(const LoweredPHIRecord &Val) { return DenseMapInfo::getHashValue(Val.PN) ^ (Val.Shift>>3) ^ @@ -589,15 +694,13 @@ namespace llvm { LHS.Width == RHS.Width; } }; - template <> - struct isPodLike { static const bool value = true; }; } -/// SliceUpIllegalIntegerPHI - This is an integer PHI and we know that it has an -/// illegal type: see if it is only used by trunc or trunc(lshr) operations. If -/// so, we split the PHI into the various pieces being extracted. This sort of -/// thing is introduced when SROA promotes an aggregate to large integer values. +/// This is an integer PHI and we know that it has an illegal type: see if it is +/// only used by trunc or trunc(lshr) operations. If so, we split the PHI into +/// the various pieces being extracted. This sort of thing is introduced when +/// SROA promotes an aggregate to large integer values. /// /// TODO: The user of the trunc may be an bitcast to float/double/vector or an /// inttoptr. We should produce new PHIs in the right type. @@ -606,107 +709,106 @@ Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) { // PHIUsers - Keep track of all of the truncated values extracted from a set // of PHIs, along with their offset. These are the things we want to rewrite. SmallVector PHIUsers; - + // PHIs are often mutually cyclic, so we keep track of a whole set of PHI // nodes which are extracted from. PHIsToSlice is a set we use to avoid // revisiting PHIs, PHIsInspected is a ordered list of PHIs that we need to // check the uses of (to ensure they are all extracts). SmallVector PHIsToSlice; SmallPtrSet PHIsInspected; - + PHIsToSlice.push_back(&FirstPhi); PHIsInspected.insert(&FirstPhi); - + for (unsigned PHIId = 0; PHIId != PHIsToSlice.size(); ++PHIId) { PHINode *PN = PHIsToSlice[PHIId]; - + // Scan the input list of the PHI. If any input is an invoke, and if the // input is defined in the predecessor, then we won't be split the critical // edge which is required to insert a truncate. Because of this, we have to // bail out. for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { InvokeInst *II = dyn_cast(PN->getIncomingValue(i)); - if (II == 0) continue; + if (!II) continue; if (II->getParent() != PN->getIncomingBlock(i)) continue; - + // If we have a phi, and if it's directly in the predecessor, then we have // a critical edge where we need to put the truncate. Since we can't // split the edge in instcombine, we have to bail out. - return 0; + return nullptr; } - - - for (Value::use_iterator UI = PN->use_begin(), E = PN->use_end(); - UI != E; ++UI) { - Instruction *User = cast(*UI); - + + for (User *U : PN->users()) { + Instruction *UserI = cast(U); + // If the user is a PHI, inspect its uses recursively. - if (PHINode *UserPN = dyn_cast(User)) { - if (PHIsInspected.insert(UserPN)) + if (PHINode *UserPN = dyn_cast(UserI)) { + if (PHIsInspected.insert(UserPN).second) PHIsToSlice.push_back(UserPN); continue; } - + // Truncates are always ok. - if (isa(User)) { - PHIUsers.push_back(PHIUsageRecord(PHIId, 0, User)); + if (isa(UserI)) { + PHIUsers.push_back(PHIUsageRecord(PHIId, 0, UserI)); continue; } - + // Otherwise it must be a lshr which can only be used by one trunc. - if (User->getOpcode() != Instruction::LShr || - !User->hasOneUse() || !isa(User->use_back()) || - !isa(User->getOperand(1))) - return 0; - - unsigned Shift = cast(User->getOperand(1))->getZExtValue(); - PHIUsers.push_back(PHIUsageRecord(PHIId, Shift, User->use_back())); + if (UserI->getOpcode() != Instruction::LShr || + !UserI->hasOneUse() || !isa(UserI->user_back()) || + !isa(UserI->getOperand(1))) + return nullptr; + + unsigned Shift = cast(UserI->getOperand(1))->getZExtValue(); + PHIUsers.push_back(PHIUsageRecord(PHIId, Shift, UserI->user_back())); } } - + // If we have no users, they must be all self uses, just nuke the PHI. if (PHIUsers.empty()) return ReplaceInstUsesWith(FirstPhi, UndefValue::get(FirstPhi.getType())); - + // If this phi node is transformable, create new PHIs for all the pieces // extracted out of it. First, sort the users by their offset and size. array_pod_sort(PHIUsers.begin(), PHIUsers.end()); - - DEBUG(errs() << "SLICING UP PHI: " << FirstPhi << '\n'; - for (unsigned i = 1, e = PHIsToSlice.size(); i != e; ++i) - errs() << "AND USER PHI #" << i << ": " << *PHIsToSlice[i] <<'\n'; - ); - + + DEBUG(dbgs() << "SLICING UP PHI: " << FirstPhi << '\n'; + for (unsigned i = 1, e = PHIsToSlice.size(); i != e; ++i) + dbgs() << "AND USER PHI #" << i << ": " << *PHIsToSlice[i] << '\n'; + ); + // PredValues - This is a temporary used when rewriting PHI nodes. It is // hoisted out here to avoid construction/destruction thrashing. DenseMap PredValues; - + // ExtractedVals - Each new PHI we introduce is saved here so we don't // introduce redundant PHIs. DenseMap ExtractedVals; - + for (unsigned UserI = 0, UserE = PHIUsers.size(); UserI != UserE; ++UserI) { unsigned PHIId = PHIUsers[UserI].PHIId; PHINode *PN = PHIsToSlice[PHIId]; unsigned Offset = PHIUsers[UserI].Shift; - const Type *Ty = PHIUsers[UserI].Inst->getType(); - + Type *Ty = PHIUsers[UserI].Inst->getType(); + PHINode *EltPHI; - + // If we've already lowered a user like this, reuse the previously lowered // value. - if ((EltPHI = ExtractedVals[LoweredPHIRecord(PN, Offset, Ty)]) == 0) { - + if ((EltPHI = ExtractedVals[LoweredPHIRecord(PN, Offset, Ty)]) == nullptr) { + // Otherwise, Create the new PHI node for this user. - EltPHI = PHINode::Create(Ty, PN->getName()+".off"+Twine(Offset), PN); + EltPHI = PHINode::Create(Ty, PN->getNumIncomingValues(), + PN->getName()+".off"+Twine(Offset), PN); assert(EltPHI->getType() != PN->getType() && "Truncate didn't shrink phi?"); - + for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { BasicBlock *Pred = PN->getIncomingBlock(i); Value *&PredVal = PredValues[Pred]; - + // If we already have a value for this predecessor, reuse it. if (PredVal) { EltPHI->addIncoming(PredVal, Pred); @@ -720,7 +822,7 @@ Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) { EltPHI->addIncoming(PredVal, Pred); continue; } - + if (PHINode *InPHI = dyn_cast(PN)) { // If the incoming value was a PHI, and if it was one of the PHIs we // already rewrote it, just use the lowered value. @@ -730,9 +832,9 @@ Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) { continue; } } - + // Otherwise, do an extract in the predecessor. - Builder->SetInsertPoint(Pred, Pred->getTerminator()); + Builder->SetInsertPoint(Pred->getTerminator()); Value *Res = InVal; if (Offset) Res = Builder->CreateLShr(Res, ConstantInt::get(InVal->getType(), @@ -740,7 +842,7 @@ Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) { Res = Builder->CreateTrunc(Res, Ty, "extract.t"); PredVal = Res; EltPHI->addIncoming(Res, Pred); - + // If the incoming value was a PHI, and if it was one of the PHIs we are // rewriting, we will ultimately delete the code we inserted. This // means we need to revisit that PHI to make sure we extract out the @@ -749,22 +851,22 @@ Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) { if (PHIsInspected.count(OldInVal)) { unsigned RefPHIId = std::find(PHIsToSlice.begin(),PHIsToSlice.end(), OldInVal)-PHIsToSlice.begin(); - PHIUsers.push_back(PHIUsageRecord(RefPHIId, Offset, + PHIUsers.push_back(PHIUsageRecord(RefPHIId, Offset, cast(Res))); ++UserE; } } PredValues.clear(); - - DEBUG(errs() << " Made element PHI for offset " << Offset << ": " + + DEBUG(dbgs() << " Made element PHI for offset " << Offset << ": " << *EltPHI << '\n'); ExtractedVals[LoweredPHIRecord(PN, Offset, Ty)] = EltPHI; } - + // Replace the use of this piece with the PHI node. ReplaceInstUsesWith(*PHIUsers[UserI].Inst, EltPHI); } - + // Replace all the remaining uses of the PHI nodes (self uses and the lshrs) // with undefs. Value *Undef = UndefValue::get(FirstPhi.getType()); @@ -776,12 +878,12 @@ Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) { // PHINode simplification // Instruction *InstCombiner::visitPHINode(PHINode &PN) { - // If LCSSA is around, don't mess with Phi nodes - if (MustPreserveLCSSA) return 0; - - if (Value *V = SimplifyInstruction(&PN, TD)) + if (Value *V = SimplifyInstruction(&PN, DL, TLI, DT, AC)) return ReplaceInstUsesWith(PN, V); + if (Instruction *Result = FoldPHIArgZextsIntoPHI(PN)) + return Result; + // If all PHI operands are the same operation, pull them through the PHI, // reducing code size. if (isa(PN.getIncomingValue(0)) && @@ -798,14 +900,14 @@ Instruction *InstCombiner::visitPHINode(PHINode &PN) { // this PHI only has a single use (a PHI), and if that PHI only has one use (a // PHI)... break the cycle. if (PN.hasOneUse()) { - Instruction *PHIUser = cast(PN.use_back()); + Instruction *PHIUser = cast(PN.user_back()); if (PHINode *PU = dyn_cast(PHIUser)) { SmallPtrSet PotentiallyDeadPHIs; PotentiallyDeadPHIs.insert(&PN); if (DeadPHICycle(PU, PotentiallyDeadPHIs)) return ReplaceInstUsesWith(PN, UndefValue::get(PN.getType())); } - + // If this phi has a single use, and if that use just computes a value for // the next iteration of a loop, delete the phi. This occurs with unused // induction variables, e.g. "for (int j = 0; ; ++j);". Detecting this @@ -814,7 +916,7 @@ Instruction *InstCombiner::visitPHINode(PHINode &PN) { // late. if (PHIUser->hasOneUse() && (isa(PHIUser) || isa(PHIUser)) && - PHIUser->use_back() == &PN) { + PHIUser->user_back() == &PN) { return ReplaceInstUsesWith(PN, UndefValue::get(PN.getType())); } } @@ -826,27 +928,27 @@ Instruction *InstCombiner::visitPHINode(PHINode &PN) { // quick check to see if the PHI node only contains a single non-phi value, if // so, scan to see if the phi cycle is actually equal to that value. { - unsigned InValNo = 0, NumOperandVals = PN.getNumIncomingValues(); + unsigned InValNo = 0, NumIncomingVals = PN.getNumIncomingValues(); // Scan for the first non-phi operand. - while (InValNo != NumOperandVals && + while (InValNo != NumIncomingVals && isa(PN.getIncomingValue(InValNo))) ++InValNo; - if (InValNo != NumOperandVals) { - Value *NonPhiInVal = PN.getOperand(InValNo); - + if (InValNo != NumIncomingVals) { + Value *NonPhiInVal = PN.getIncomingValue(InValNo); + // Scan the rest of the operands to see if there are any conflicts, if so // there is no need to recursively scan other phis. - for (++InValNo; InValNo != NumOperandVals; ++InValNo) { + for (++InValNo; InValNo != NumIncomingVals; ++InValNo) { Value *OpVal = PN.getIncomingValue(InValNo); if (OpVal != NonPhiInVal && !isa(OpVal)) break; } - + // If we scanned over all operands, then we have one unique value plus // phi values. Scan PHI nodes to see if they all merge in each other or // the value. - if (InValNo == NumOperandVals) { + if (InValNo == NumIncomingVals) { SmallPtrSet ValueEqualPHIs; if (PHIsEqualValue(&PN, NonPhiInVal, ValueEqualPHIs)) return ReplaceInstUsesWith(PN, NonPhiInVal); @@ -882,10 +984,10 @@ Instruction *InstCombiner::visitPHINode(PHINode &PN) { // it is only used by trunc or trunc(lshr) operations. If so, we split the // PHI into the various pieces being extracted. This sort of thing is // introduced when SROA promotes an aggregate to a single large integer type. - if (PN.getType()->isIntegerTy() && TD && - !TD->isLegalInteger(PN.getType()->getPrimitiveSizeInBits())) + if (PN.getType()->isIntegerTy() && + !DL.isLegalInteger(PN.getType()->getPrimitiveSizeInBits())) if (Instruction *Res = SliceUpIllegalIntegerPHI(PN)) return Res; - - return 0; + + return nullptr; }