diff options
Diffstat (limited to 'contrib/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp')
| -rw-r--r-- | contrib/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp | 287 |
1 files changed, 276 insertions, 11 deletions
diff --git a/contrib/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/contrib/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp index 505a0bf..79a9b09 100644 --- a/contrib/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/contrib/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -396,6 +396,11 @@ static bool CanEvaluateTruncated(Value *V, const Type *Ty) { case Instruction::Trunc: // trunc(trunc(x)) -> trunc(x) return true; + case Instruction::ZExt: + case Instruction::SExt: + // trunc(ext(x)) -> ext(x) if the source type is smaller than the new dest + // trunc(ext(x)) -> trunc(x) if the source type is larger than the new dest + return true; case Instruction::Select: { SelectInst *SI = cast<SelectInst>(I); return CanEvaluateTruncated(SI->getTrueValue(), Ty) && @@ -454,6 +459,29 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) { Value *Zero = Constant::getNullValue(Src->getType()); return new ICmpInst(ICmpInst::ICMP_NE, Src, Zero); } + + // 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()) { + // 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 + // between ASize and ResultSize. + unsigned ASize = A->getType()->getPrimitiveSizeInBits(); + + // If the shift amount is larger than the size of A, then the result is + // known to be zero because all the input bits got shifted out. + if (Cst->getZExtValue() >= ASize) + return ReplaceInstUsesWith(CI, Constant::getNullValue(CI.getType())); + + // Since we're doing an lshr and a zero extend, and know that the shift + // amount is smaller than ASize, it is always safe to do the shift in A's + // type, then zero extend or truncate to the result. + Value *Shift = Builder->CreateLShr(A, Cst->getZExtValue()); + Shift->takeName(Src); + return CastInst::CreateIntegerCast(Shift, CI.getType(), false); + } return 0; } @@ -538,8 +566,7 @@ Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, Instruction &CI, if (CI.getType() == In->getType()) return ReplaceInstUsesWith(CI, In); - else - return CastInst::CreateIntegerCast(In, CI.getType(), false/*ZExt*/); + return CastInst::CreateIntegerCast(In, CI.getType(), false/*ZExt*/); } } } @@ -1097,6 +1124,38 @@ Instruction *InstCombiner::visitFPTrunc(FPTruncInst &CI) { break; } } + + // Fold (fptrunc (sqrt (fpext x))) -> (sqrtf x) + // NOTE: This should be disabled by -fno-builtin-sqrt if we ever support it. + CallInst *Call = dyn_cast<CallInst>(CI.getOperand(0)); + if (Call && Call->getCalledFunction() && + Call->getCalledFunction()->getName() == "sqrt" && + Call->getNumArgOperands() == 1) { + CastInst *Arg = dyn_cast<CastInst>(Call->getArgOperand(0)); + if (Arg && Arg->getOpcode() == Instruction::FPExt && + CI.getType()->isFloatTy() && + Call->getType()->isDoubleTy() && + Arg->getType()->isDoubleTy() && + Arg->getOperand(0)->getType()->isFloatTy()) { + Function *Callee = Call->getCalledFunction(); + Module *M = CI.getParent()->getParent()->getParent(); + Constant *SqrtfFunc = M->getOrInsertFunction("sqrtf", + Callee->getAttributes(), + Builder->getFloatTy(), + Builder->getFloatTy(), + NULL); + 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. + Call->replaceAllUsesWith(UndefValue::get(Call->getType())); + EraseInstFromFunction(*Call); + return ret; + } + } + return 0; } @@ -1308,6 +1367,199 @@ static Instruction *OptimizeVectorResize(Value *InVal, const VectorType *DestTy, return new ShuffleVectorInst(InVal, V2, Mask); } +static bool isMultipleOfTypeSize(unsigned Value, const Type *Ty) { + return Value % Ty->getPrimitiveSizeInBits() == 0; +} + +static unsigned getTypeSizeIndex(unsigned Value, const Type *Ty) { + return Value / Ty->getPrimitiveSizeInBits(); +} + +/// CollectInsertionElements - V is a value which is inserted into a vector of +/// VecEltTy. Look through the value to see if we can decompose it into +/// insertions into the vector. See the example in the comment for +/// OptimizeIntegerToVectorInsertions for the pattern this handles. +/// The type of V is always a non-zero multiple of VecEltTy's size. +/// +/// This returns false if the pattern can't be matched or true if it can, +/// filling in Elements with the elements found here. +static bool CollectInsertionElements(Value *V, unsigned ElementIndex, + SmallVectorImpl<Value*> &Elements, + const Type *VecEltTy) { + // Undef values never contribute useful bits to the result. + if (isa<UndefValue>(V)) return true; + + // If we got down to a value of the right type, we win, try inserting into the + // right element. + if (V->getType() == VecEltTy) { + // Inserting null doesn't actually insert any elements. + if (Constant *C = dyn_cast<Constant>(V)) + if (C->isNullValue()) + return true; + + // Fail if multiple elements are inserted into this slot. + if (ElementIndex >= Elements.size() || Elements[ElementIndex] != 0) + return false; + + Elements[ElementIndex] = V; + return true; + } + + if (Constant *C = dyn_cast<Constant>(V)) { + // Figure out the # elements this provides, and bitcast it or slice it up + // as required. + unsigned NumElts = getTypeSizeIndex(C->getType()->getPrimitiveSizeInBits(), + VecEltTy); + // If the constant is the size of a vector element, we just need to bitcast + // it to the right type so it gets properly inserted. + if (NumElts == 1) + return CollectInsertionElements(ConstantExpr::getBitCast(C, VecEltTy), + ElementIndex, Elements, VecEltTy); + + // Okay, this is a constant that covers multiple elements. Slice it up into + // pieces and insert each element-sized piece into the vector. + if (!isa<IntegerType>(C->getType())) + C = ConstantExpr::getBitCast(C, IntegerType::get(V->getContext(), + C->getType()->getPrimitiveSizeInBits())); + unsigned ElementSize = VecEltTy->getPrimitiveSizeInBits(); + const Type *ElementIntTy = IntegerType::get(C->getContext(), ElementSize); + + for (unsigned i = 0; i != NumElts; ++i) { + Constant *Piece = ConstantExpr::getLShr(C, ConstantInt::get(C->getType(), + i*ElementSize)); + Piece = ConstantExpr::getTrunc(Piece, ElementIntTy); + if (!CollectInsertionElements(Piece, ElementIndex+i, Elements, VecEltTy)) + return false; + } + return true; + } + + if (!V->hasOneUse()) return false; + + Instruction *I = dyn_cast<Instruction>(V); + if (I == 0) return false; + switch (I->getOpcode()) { + default: return false; // Unhandled case. + case Instruction::BitCast: + return CollectInsertionElements(I->getOperand(0), ElementIndex, + Elements, VecEltTy); + case Instruction::ZExt: + if (!isMultipleOfTypeSize( + I->getOperand(0)->getType()->getPrimitiveSizeInBits(), + VecEltTy)) + return false; + return CollectInsertionElements(I->getOperand(0), ElementIndex, + Elements, VecEltTy); + case Instruction::Or: + return CollectInsertionElements(I->getOperand(0), ElementIndex, + Elements, VecEltTy) && + CollectInsertionElements(I->getOperand(1), ElementIndex, + Elements, VecEltTy); + case Instruction::Shl: { + // Must be shifting by a constant that is a multiple of the element size. + ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1)); + if (CI == 0) return false; + if (!isMultipleOfTypeSize(CI->getZExtValue(), VecEltTy)) return false; + unsigned IndexShift = getTypeSizeIndex(CI->getZExtValue(), VecEltTy); + + return CollectInsertionElements(I->getOperand(0), ElementIndex+IndexShift, + Elements, VecEltTy); + } + + } +} + + +/// OptimizeIntegerToVectorInsertions - If the input is an 'or' instruction, we +/// may be doing shifts and ors to assemble the elements of the vector manually. +/// Try to rip the code out and replace it with insertelements. This is to +/// optimize code like this: +/// +/// %tmp37 = bitcast float %inc to i32 +/// %tmp38 = zext i32 %tmp37 to i64 +/// %tmp31 = bitcast float %inc5 to i32 +/// %tmp32 = zext i32 %tmp31 to i64 +/// %tmp33 = shl i64 %tmp32, 32 +/// %ins35 = or i64 %tmp33, %tmp38 +/// %tmp43 = bitcast i64 %ins35 to <2 x float> +/// +/// Into two insertelements that do "buildvector{%inc, %inc5}". +static Value *OptimizeIntegerToVectorInsertions(BitCastInst &CI, + InstCombiner &IC) { + const VectorType *DestVecTy = cast<VectorType>(CI.getType()); + Value *IntInput = CI.getOperand(0); + + SmallVector<Value*, 8> Elements(DestVecTy->getNumElements()); + if (!CollectInsertionElements(IntInput, 0, Elements, + DestVecTy->getElementType())) + return 0; + + // If we succeeded, we know that all of the element are specified by Elements + // or are zero if Elements has a null entry. Recast this as a set of + // insertions. + Value *Result = Constant::getNullValue(CI.getType()); + for (unsigned i = 0, e = Elements.size(); i != e; ++i) { + if (Elements[i] == 0) continue; // Unset element. + + Result = IC.Builder->CreateInsertElement(Result, Elements[i], + IC.Builder->getInt32(i)); + } + + return Result; +} + + +/// OptimizeIntToFloatBitCast - See if we can optimize an integer->float/double +/// bitcast. The various long double bitcasts can't get in here. +static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI,InstCombiner &IC){ + Value *Src = CI.getOperand(0); + const Type *DestTy = CI.getType(); + + // If this is a bitcast from int to float, check to see if the int is an + // extraction from a vector. + Value *VecInput = 0; + // bitcast(trunc(bitcast(somevector))) + if (match(Src, m_Trunc(m_BitCast(m_Value(VecInput)))) && + isa<VectorType>(VecInput->getType())) { + const VectorType *VecTy = cast<VectorType>(VecInput->getType()); + unsigned DestWidth = DestTy->getPrimitiveSizeInBits(); + + if (VecTy->getPrimitiveSizeInBits() % DestWidth == 0) { + // If the element type of the vector doesn't match the result type, + // bitcast it to be a vector type we can extract from. + if (VecTy->getElementType() != DestTy) { + VecTy = VectorType::get(DestTy, + VecTy->getPrimitiveSizeInBits() / DestWidth); + VecInput = IC.Builder->CreateBitCast(VecInput, VecTy); + } + + return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(0)); + } + } + + // bitcast(trunc(lshr(bitcast(somevector), cst)) + ConstantInt *ShAmt = 0; + if (match(Src, m_Trunc(m_LShr(m_BitCast(m_Value(VecInput)), + m_ConstantInt(ShAmt)))) && + isa<VectorType>(VecInput->getType())) { + const VectorType *VecTy = cast<VectorType>(VecInput->getType()); + unsigned DestWidth = DestTy->getPrimitiveSizeInBits(); + if (VecTy->getPrimitiveSizeInBits() % DestWidth == 0 && + ShAmt->getZExtValue() % DestWidth == 0) { + // If the element type of the vector doesn't match the result type, + // bitcast it to be a vector type we can extract from. + if (VecTy->getElementType() != DestTy) { + VecTy = VectorType::get(DestTy, + VecTy->getPrimitiveSizeInBits() / DestWidth); + VecInput = IC.Builder->CreateBitCast(VecInput, VecTy); + } + + unsigned Elt = ShAmt->getZExtValue() / DestWidth; + return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt)); + } + } + return 0; +} Instruction *InstCombiner::visitBitCast(BitCastInst &CI) { // If the operands are integer typed then apply the integer transforms, @@ -1359,6 +1611,11 @@ Instruction *InstCombiner::visitBitCast(BitCastInst &CI) { ((Instruction*)NULL)); } } + + // Try to optimize int -> float bitcasts. + if ((DestTy->isFloatTy() || DestTy->isDoubleTy()) && isa<IntegerType>(SrcTy)) + if (Instruction *I = OptimizeIntToFloatBitCast(CI, *this)) + return I; if (const VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) { if (DestVTy->getNumElements() == 1 && !SrcTy->isVectorTy()) { @@ -1368,16 +1625,24 @@ Instruction *InstCombiner::visitBitCast(BitCastInst &CI) { // FIXME: Canonicalize bitcast(insertelement) -> insertelement(bitcast) } - // If this is a cast from an integer to vector, check to see if the input - // is a trunc or zext of a bitcast from vector. If so, we can replace all - // the casts with a shuffle and (potentially) a bitcast. - if (isa<IntegerType>(SrcTy) && (isa<TruncInst>(Src) || isa<ZExtInst>(Src))){ - CastInst *SrcCast = cast<CastInst>(Src); - if (BitCastInst *BCIn = dyn_cast<BitCastInst>(SrcCast->getOperand(0))) - if (isa<VectorType>(BCIn->getOperand(0)->getType())) - if (Instruction *I = OptimizeVectorResize(BCIn->getOperand(0), + if (isa<IntegerType>(SrcTy)) { + // If this is a cast from an integer to vector, check to see if the input + // is a trunc or zext of a bitcast from vector. If so, we can replace all + // the casts with a shuffle and (potentially) a bitcast. + if (isa<TruncInst>(Src) || isa<ZExtInst>(Src)) { + CastInst *SrcCast = cast<CastInst>(Src); + if (BitCastInst *BCIn = dyn_cast<BitCastInst>(SrcCast->getOperand(0))) + if (isa<VectorType>(BCIn->getOperand(0)->getType())) + if (Instruction *I = OptimizeVectorResize(BCIn->getOperand(0), cast<VectorType>(DestTy), *this)) - return I; + return I; + } + + // If the input is an 'or' instruction, we may be doing shifts and ors to + // assemble the elements of the vector manually. Try to rip the code out + // and replace it with insertelements. + if (Value *V = OptimizeIntegerToVectorInsertions(CI, *this)) + return ReplaceInstUsesWith(CI, V); } } |
