X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FInstCombine%2FInstCombineCasts.cpp;h=601d9b42f31454c4157c0344a75b6342bde41730;hb=73f50d9bc3bd46cc0abeba9bb0d46977ba1aea42;hp=6c2477d52c77578e8fc5313c1c3fbace31d5f838;hpb=157d4ead36ace978a01d80a29aa1b53c832ebafb;p=oota-llvm.git diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp index 6c2477d52c7..601d9b42f31 100644 --- a/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -71,6 +71,11 @@ Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI, // This requires TargetData to get the alloca alignment and size information. if (!TD) return 0; + // Insist that the amount-to-allocate not overflow. + OverflowingBinaryOperator *OBI = + dyn_cast(AI.getOperand(0)); + if (OBI && !(OBI->hasNoSignedWrap() || OBI->hasNoUnsignedWrap())) return 0; + const PointerType *PTy = cast(CI.getType()); BuilderTy AllocaBuilder(*Builder); @@ -87,10 +92,8 @@ Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI, // If the allocation has multiple uses, only promote it if we are strictly // increasing the alignment of the resultant allocation. If we keep it the - // same, we open the door to infinite loops of various kinds. (A reference - // from a dbg.declare doesn't count as a use for this purpose.) - if (!AI.hasOneUse() && !hasOneUsePlusDeclare(&AI) && - CastElTyAlign == AllocElTyAlign) return 0; + // same, we open the door to infinite loops of various kinds. + if (!AI.hasOneUse() && CastElTyAlign == AllocElTyAlign) return 0; uint64_t AllocElTySize = TD->getTypeAllocSize(AllocElTy); uint64_t CastElTySize = TD->getTypeAllocSize(CastElTy); @@ -128,19 +131,14 @@ Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI, New->setAlignment(AI.getAlignment()); New->takeName(&AI); - // If the allocation has one real use plus a dbg.declare, just remove the - // declare. - if (DbgDeclareInst *DI = hasOneUsePlusDeclare(&AI)) { - EraseInstFromFunction(*(Instruction*)DI); - } // If the allocation has multiple real uses, insert a cast and change all // things that used it to use the new cast. This will also hack on CI, but it // will die soon. - else if (!AI.hasOneUse()) { + if (!AI.hasOneUse()) { // New is the allocation instruction, pointer typed. AI is the original // allocation instruction, also pointer typed. Thus, cast to use is BitCast. Value *NewCast = AllocaBuilder.CreateBitCast(New, AI.getType(), "tmpcast"); - AI.replaceAllUsesWith(NewCast); + ReplaceInstUsesWith(AI, NewCast); } return ReplaceInstUsesWith(CI, New); } @@ -203,7 +201,7 @@ Value *InstCombiner::EvaluateInDifferentType(Value *V, const Type *Ty, } case Instruction::PHI: { PHINode *OPN = cast(I); - PHINode *NPN = PHINode::Create(Ty); + PHINode *NPN = PHINode::Create(Ty, OPN->getNumIncomingValues()); for (unsigned i = 0, e = OPN->getNumIncomingValues(); i != e; ++i) { Value *V =EvaluateInDifferentType(OPN->getIncomingValue(i), Ty, isSigned); NPN->addIncoming(V, OPN->getIncomingBlock(i)); @@ -218,7 +216,7 @@ Value *InstCombiner::EvaluateInDifferentType(Value *V, const Type *Ty, } Res->takeName(I); - return InsertNewInstBefore(Res, *I); + return InsertNewInstWith(Res, *I); } @@ -462,8 +460,8 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) { // Transform trunc(lshr (zext A), Cst) to eliminate one type conversion. Value *A = 0; ConstantInt *Cst = 0; - if (match(Src, m_LShr(m_ZExt(m_Value(A)), m_ConstantInt(Cst))) && - Src->hasOneUse()) { + if (Src->hasOneUse() && + match(Src, m_LShr(m_ZExt(m_Value(A)), m_ConstantInt(Cst)))) { // We have three types to worry about here, the type of A, the source of // the truncate (MidSize), and the destination of the truncate. We know that // ASize < MidSize and MidSize > ResultSize, but don't know the relation @@ -482,6 +480,16 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) { Shift->takeName(Src); return CastInst::CreateIntegerCast(Shift, CI.getType(), false); } + + // Transform "trunc (and X, cst)" -> "and (trunc X), cst" so long as the dest + // type isn't non-native. + if (Src->hasOneUse() && isa(Src->getType()) && + ShouldChangeType(Src->getType(), CI.getType()) && + match(Src, m_And(m_Value(A), m_ConstantInt(Cst)))) { + Value *NewTrunc = Builder->CreateTrunc(A, CI.getType(), A->getName()+".tr"); + return BinaryOperator::CreateAnd(NewTrunc, + ConstantExpr::getTrunc(Cst, CI.getType())); + } return 0; } @@ -873,6 +881,102 @@ Instruction *InstCombiner::visitZExt(ZExtInst &CI) { return 0; } +/// transformSExtICmp - Transform (sext icmp) to bitwise / integer operations +/// in order to eliminate the icmp. +Instruction *InstCombiner::transformSExtICmp(ICmpInst *ICI, Instruction &CI) { + Value *Op0 = ICI->getOperand(0), *Op1 = ICI->getOperand(1); + ICmpInst::Predicate Pred = ICI->getPredicate(); + + if (ConstantInt *Op1C = dyn_cast(Op1)) { + // (x ashr x, 31 -> all ones if negative + // (x >s -1) ? -1 : 0 -> not (ashr x, 31) -> all ones if positive + if ((Pred == ICmpInst::ICMP_SLT && Op1C->isZero()) || + (Pred == ICmpInst::ICMP_SGT && Op1C->isAllOnesValue())) { + + Value *Sh = ConstantInt::get(Op0->getType(), + Op0->getType()->getScalarSizeInBits()-1); + Value *In = Builder->CreateAShr(Op0, Sh, Op0->getName()+".lobit"); + if (In->getType() != CI.getType()) + In = Builder->CreateIntCast(In, CI.getType(), true/*SExt*/, "tmp"); + + if (Pred == ICmpInst::ICMP_SGT) + In = Builder->CreateNot(In, In->getName()+".not"); + return ReplaceInstUsesWith(CI, In); + } + + // If we know that only one bit of the LHS of the icmp can be set and we + // have an equality comparison with zero or a power of 2, we can transform + // the icmp and sext into bitwise/integer operations. + if (ICI->hasOneUse() && + ICI->isEquality() && (Op1C->isZero() || Op1C->getValue().isPowerOf2())){ + unsigned BitWidth = Op1C->getType()->getBitWidth(); + APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); + APInt TypeMask(APInt::getAllOnesValue(BitWidth)); + ComputeMaskedBits(Op0, TypeMask, KnownZero, KnownOne); + + APInt KnownZeroMask(~KnownZero); + if (KnownZeroMask.isPowerOf2()) { + Value *In = ICI->getOperand(0); + + // If the icmp tests for a known zero bit we can constant fold it. + if (!Op1C->isZero() && Op1C->getValue() != KnownZeroMask) { + Value *V = Pred == ICmpInst::ICMP_NE ? + ConstantInt::getAllOnesValue(CI.getType()) : + ConstantInt::getNullValue(CI.getType()); + return ReplaceInstUsesWith(CI, V); + } + + if (!Op1C->isZero() == (Pred == ICmpInst::ICMP_NE)) { + // sext ((x & 2^n) == 0) -> (x >> n) - 1 + // sext ((x & 2^n) != 2^n) -> (x >> n) - 1 + unsigned ShiftAmt = KnownZeroMask.countTrailingZeros(); + // Perform a right shift to place the desired bit in the LSB. + if (ShiftAmt) + In = Builder->CreateLShr(In, + ConstantInt::get(In->getType(), ShiftAmt)); + + // At this point "In" is either 1 or 0. Subtract 1 to turn + // {1, 0} -> {0, -1}. + In = Builder->CreateAdd(In, + ConstantInt::getAllOnesValue(In->getType()), + "sext"); + } else { + // sext ((x & 2^n) != 0) -> (x << bitwidth-n) a>> bitwidth-1 + // sext ((x & 2^n) == 2^n) -> (x << bitwidth-n) a>> bitwidth-1 + unsigned ShiftAmt = KnownZeroMask.countLeadingZeros(); + // Perform a left shift to place the desired bit in the MSB. + if (ShiftAmt) + In = Builder->CreateShl(In, + ConstantInt::get(In->getType(), ShiftAmt)); + + // Distribute the bit over the whole bit width. + In = Builder->CreateAShr(In, ConstantInt::get(In->getType(), + BitWidth - 1), "sext"); + } + + if (CI.getType() == In->getType()) + return ReplaceInstUsesWith(CI, In); + return CastInst::CreateIntegerCast(In, CI.getType(), true/*SExt*/); + } + } + } + + // vector (x ashr x, 31 -> all ones if signed. + if (const VectorType *VTy = dyn_cast(CI.getType())) { + if (Pred == ICmpInst::ICMP_SLT && match(Op1, m_Zero()) && + Op0->getType() == CI.getType()) { + const Type *EltTy = VTy->getElementType(); + + // splat the shift constant to a constant vector. + Constant *VSh = ConstantInt::get(VTy, EltTy->getScalarSizeInBits()-1); + Value *In = Builder->CreateAShr(Op0, VSh, Op0->getName()+".lobit"); + return ReplaceInstUsesWith(CI, In); + } + } + + return 0; +} + /// CanEvaluateSExtd - Return true if we can take the specified value /// and return it as type Ty without inserting any new casts and without /// changing the value of the common low bits. This is used by code that tries @@ -996,31 +1100,10 @@ Instruction *InstCombiner::visitSExt(SExtInst &CI) { Value *Res = Builder->CreateShl(TI->getOperand(0), ShAmt, "sext"); return BinaryOperator::CreateAShr(Res, ShAmt); } - - - // (x ashr x, 31 -> all ones if signed - // (x >s -1) ? -1 : 0 -> ashr x, 31 -> all ones if not signed - { - ICmpInst::Predicate Pred; Value *CmpLHS; ConstantInt *CmpRHS; - if (match(Src, m_ICmp(Pred, m_Value(CmpLHS), m_ConstantInt(CmpRHS)))) { - // sext (x x>>s31 true if signbit set. - // sext (x >s -1) to i32 --> (x>>s31)^-1 true if signbit clear. - if ((Pred == ICmpInst::ICMP_SLT && CmpRHS->isZero()) || - (Pred == ICmpInst::ICMP_SGT && CmpRHS->isAllOnesValue())) { - Value *Sh = ConstantInt::get(CmpLHS->getType(), - CmpLHS->getType()->getScalarSizeInBits()-1); - Value *In = Builder->CreateAShr(CmpLHS, Sh, CmpLHS->getName()+".lobit"); - if (In->getType() != CI.getType()) - In = Builder->CreateIntCast(In, CI.getType(), true/*SExt*/, "tmp"); - - if (Pred == ICmpInst::ICMP_SGT) - In = Builder->CreateNot(In, In->getName()+".not"); - return ReplaceInstUsesWith(CI, In); - } - } - } - - + + if (ICmpInst *ICI = dyn_cast(Src)) + return transformSExtICmp(ICI, CI); + // If the input is a shl/ashr pair of a same constant, then this is a sign // extension from a smaller value. If we could trust arbitrary bitwidth // integers, we could turn this into a truncate to the smaller bit and then @@ -1139,7 +1222,7 @@ Instruction *InstCombiner::visitFPTrunc(FPTruncInst &CI) { Arg->getOperand(0)->getType()->isFloatTy()) { Function *Callee = Call->getCalledFunction(); Module *M = CI.getParent()->getParent()->getParent(); - Constant* SqrtfFunc = M->getOrInsertFunction("sqrtf", + Constant *SqrtfFunc = M->getOrInsertFunction("sqrtf", Callee->getAttributes(), Builder->getFloatTy(), Builder->getFloatTy(), @@ -1147,6 +1230,11 @@ Instruction *InstCombiner::visitFPTrunc(FPTruncInst &CI) { CallInst *ret = CallInst::Create(SqrtfFunc, Arg->getOperand(0), "sqrtfcall"); ret->setAttributes(Callee->getAttributes()); + + + // Remove the old Call. With -fmath-errno, it won't get marked readnone. + ReplaceInstUsesWith(*Call, UndefValue::get(Call->getType())); + EraseInstFromFunction(*Call); return ret; } } @@ -1358,8 +1446,7 @@ static Instruction *OptimizeVectorResize(Value *InVal, const VectorType *DestTy, ConstantInt::get(Int32Ty, SrcElts)); } - Constant *Mask = ConstantVector::get(ShuffleMask.data(), ShuffleMask.size()); - return new ShuffleVectorInst(InVal, V2, Mask); + return new ShuffleVectorInst(InVal, V2, ConstantVector::get(ShuffleMask)); } static bool isMultipleOfTypeSize(unsigned Value, const Type *Ty) { @@ -1602,8 +1689,7 @@ Instruction *InstCombiner::visitBitCast(BitCastInst &CI) { // If we found a path from the src to dest, create the getelementptr now. if (SrcElTy == DstElTy) { SmallVector Idxs(NumZeros+1, ZeroUInt); - return GetElementPtrInst::CreateInBounds(Src, Idxs.begin(), Idxs.end(),"", - ((Instruction*)NULL)); + return GetElementPtrInst::CreateInBounds(Src, Idxs.begin(), Idxs.end()); } }