diff options
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineMulDivRem.cpp')
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 258 |
1 files changed, 193 insertions, 65 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index e36b762..cc6a301 100644 --- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -338,13 +338,13 @@ static bool isFMulOrFDivWithConstant(Value *V) { if (C0 && C1) return false; - return (C0 && C0->getValueAPF().isNormal()) || - (C1 && C1->getValueAPF().isNormal()); + return (C0 && C0->getValueAPF().isFiniteNonZero()) || + (C1 && C1->getValueAPF().isFiniteNonZero()); } static bool isNormalFp(const ConstantFP *C) { const APFloat &Flt = C->getValueAPF(); - return Flt.isNormal() && !Flt.isDenormal(); + return Flt.isNormal(); } /// foldFMulConst() is a helper routine of InstCombiner::visitFMul(). @@ -423,7 +423,7 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) { return NV; ConstantFP *C = dyn_cast<ConstantFP>(Op1); - if (C && AllowReassociate && C->getValueAPF().isNormal()) { + if (C && AllowReassociate && C->getValueAPF().isFiniteNonZero()) { // Let MDC denote an expression in one of these forms: // X * C, C/X, X/C, where C is a constant. // @@ -450,7 +450,7 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) { Swap = true; } - if (C1 && C1->getValueAPF().isNormal() && + if (C1 && C1->getValueAPF().isFiniteNonZero() && isFMulOrFDivWithConstant(Opnd0)) { Value *M1 = ConstantExpr::getFMul(C1, C); Value *M0 = isNormalFp(cast<ConstantFP>(M1)) ? @@ -556,6 +556,35 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) { } } + // B * (uitofp i1 C) -> select C, B, 0 + if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) { + Value *LHS = Op0, *RHS = Op1; + Value *B, *C; + if (!match(RHS, m_UIToFP(m_Value(C)))) + std::swap(LHS, RHS); + + if (match(RHS, m_UIToFP(m_Value(C))) && C->getType()->isIntegerTy(1)) { + B = LHS; + Value *Zero = ConstantFP::getNegativeZero(B->getType()); + return SelectInst::Create(C, B, Zero); + } + } + + // A * (1 - uitofp i1 C) -> select C, 0, A + if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) { + Value *LHS = Op0, *RHS = Op1; + Value *A, *C; + if (!match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C))))) + std::swap(LHS, RHS); + + if (match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C)))) && + C->getType()->isIntegerTy(1)) { + A = LHS; + Value *Zero = ConstantFP::getNegativeZero(A->getType()); + return SelectInst::Create(C, Zero, A); + } + } + if (!isa<Constant>(Op1)) std::swap(Opnd0, Opnd1); else @@ -705,40 +734,124 @@ static Value *dyn_castZExtVal(Value *V, Type *Ty) { return 0; } -Instruction *InstCombiner::visitUDiv(BinaryOperator &I) { - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); +namespace { +const unsigned MaxDepth = 6; +typedef Instruction *(*FoldUDivOperandCb)(Value *Op0, Value *Op1, + const BinaryOperator &I, + InstCombiner &IC); + +/// \brief Used to maintain state for visitUDivOperand(). +struct UDivFoldAction { + FoldUDivOperandCb FoldAction; ///< Informs visitUDiv() how to fold this + ///< operand. This can be zero if this action + ///< joins two actions together. + + Value *OperandToFold; ///< Which operand to fold. + union { + Instruction *FoldResult; ///< The instruction returned when FoldAction is + ///< invoked. + + size_t SelectLHSIdx; ///< Stores the LHS action index if this action + ///< joins two actions together. + }; + + UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand) + : FoldAction(FA), OperandToFold(InputOperand), FoldResult(0) {} + UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand, size_t SLHS) + : FoldAction(FA), OperandToFold(InputOperand), SelectLHSIdx(SLHS) {} +}; +} - if (Value *V = SimplifyUDivInst(Op0, Op1, TD)) - return ReplaceInstUsesWith(I, V); +// X udiv 2^C -> X >> C +static Instruction *foldUDivPow2Cst(Value *Op0, Value *Op1, + const BinaryOperator &I, InstCombiner &IC) { + const APInt &C = cast<Constant>(Op1)->getUniqueInteger(); + BinaryOperator *LShr = BinaryOperator::CreateLShr( + Op0, ConstantInt::get(Op0->getType(), C.logBase2())); + if (I.isExact()) LShr->setIsExact(); + return LShr; +} - // Handle the integer div common cases - if (Instruction *Common = commonIDivTransforms(I)) - return Common; +// X udiv C, where C >= signbit +static Instruction *foldUDivNegCst(Value *Op0, Value *Op1, + const BinaryOperator &I, InstCombiner &IC) { + Value *ICI = IC.Builder->CreateICmpULT(Op0, cast<ConstantInt>(Op1)); - { - // X udiv 2^C -> X >> C - // Check to see if this is an unsigned division with an exact power of 2, - // if so, convert to a right shift. - const APInt *C; - if (match(Op1, m_Power2(C))) { - BinaryOperator *LShr = - BinaryOperator::CreateLShr(Op0, - ConstantInt::get(Op0->getType(), - C->logBase2())); - if (I.isExact()) LShr->setIsExact(); - return LShr; - } + return SelectInst::Create(ICI, Constant::getNullValue(I.getType()), + ConstantInt::get(I.getType(), 1)); +} + +// X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2) +static Instruction *foldUDivShl(Value *Op0, Value *Op1, const BinaryOperator &I, + InstCombiner &IC) { + Instruction *ShiftLeft = cast<Instruction>(Op1); + if (isa<ZExtInst>(ShiftLeft)) + ShiftLeft = cast<Instruction>(ShiftLeft->getOperand(0)); + + const APInt &CI = + cast<Constant>(ShiftLeft->getOperand(0))->getUniqueInteger(); + Value *N = ShiftLeft->getOperand(1); + if (CI != 1) + N = IC.Builder->CreateAdd(N, ConstantInt::get(N->getType(), CI.logBase2())); + if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1)) + N = IC.Builder->CreateZExt(N, Z->getDestTy()); + BinaryOperator *LShr = BinaryOperator::CreateLShr(Op0, N); + if (I.isExact()) LShr->setIsExact(); + return LShr; +} + +// \brief Recursively visits the possible right hand operands of a udiv +// instruction, seeing through select instructions, to determine if we can +// replace the udiv with something simpler. If we find that an operand is not +// able to simplify the udiv, we abort the entire transformation. +static size_t visitUDivOperand(Value *Op0, Value *Op1, const BinaryOperator &I, + SmallVectorImpl<UDivFoldAction> &Actions, + unsigned Depth = 0) { + // Check to see if this is an unsigned division with an exact power of 2, + // if so, convert to a right shift. + if (match(Op1, m_Power2())) { + Actions.push_back(UDivFoldAction(foldUDivPow2Cst, Op1)); + return Actions.size(); } - if (ConstantInt *C = dyn_cast<ConstantInt>(Op1)) { + if (ConstantInt *C = dyn_cast<ConstantInt>(Op1)) // X udiv C, where C >= signbit if (C->getValue().isNegative()) { - Value *IC = Builder->CreateICmpULT(Op0, C); - return SelectInst::Create(IC, Constant::getNullValue(I.getType()), - ConstantInt::get(I.getType(), 1)); + Actions.push_back(UDivFoldAction(foldUDivNegCst, C)); + return Actions.size(); } + + // X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2) + if (match(Op1, m_Shl(m_Power2(), m_Value())) || + match(Op1, m_ZExt(m_Shl(m_Power2(), m_Value())))) { + Actions.push_back(UDivFoldAction(foldUDivShl, Op1)); + return Actions.size(); } + // The remaining tests are all recursive, so bail out if we hit the limit. + if (Depth++ == MaxDepth) + return 0; + + if (SelectInst *SI = dyn_cast<SelectInst>(Op1)) + if (size_t LHSIdx = visitUDivOperand(Op0, SI->getOperand(1), I, Actions)) + if (visitUDivOperand(Op0, SI->getOperand(2), I, Actions)) { + Actions.push_back(UDivFoldAction((FoldUDivOperandCb)0, Op1, LHSIdx-1)); + return Actions.size(); + } + + return 0; +} + +Instruction *InstCombiner::visitUDiv(BinaryOperator &I) { + Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); + + if (Value *V = SimplifyUDivInst(Op0, Op1, TD)) + return ReplaceInstUsesWith(I, V); + + // Handle the integer div common cases + if (Instruction *Common = commonIDivTransforms(I)) + return Common; + // (x lshr C1) udiv C2 --> x udiv (C2 << C1) if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) { Value *X; @@ -749,38 +862,6 @@ Instruction *InstCombiner::visitUDiv(BinaryOperator &I) { } } - // X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2) - { const APInt *CI; Value *N; - if (match(Op1, m_Shl(m_Power2(CI), m_Value(N))) || - match(Op1, m_ZExt(m_Shl(m_Power2(CI), m_Value(N))))) { - if (*CI != 1) - N = Builder->CreateAdd(N, - ConstantInt::get(N->getType(), CI->logBase2())); - if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1)) - N = Builder->CreateZExt(N, Z->getDestTy()); - if (I.isExact()) - return BinaryOperator::CreateExactLShr(Op0, N); - return BinaryOperator::CreateLShr(Op0, N); - } - } - - // udiv X, (Select Cond, C1, C2) --> Select Cond, (shr X, C1), (shr X, C2) - // where C1&C2 are powers of two. - { Value *Cond; const APInt *C1, *C2; - if (match(Op1, m_Select(m_Value(Cond), m_Power2(C1), m_Power2(C2)))) { - // Construct the "on true" case of the select - Value *TSI = Builder->CreateLShr(Op0, C1->logBase2(), Op1->getName()+".t", - I.isExact()); - - // Construct the "on false" case of the select - Value *FSI = Builder->CreateLShr(Op0, C2->logBase2(), Op1->getName()+".f", - I.isExact()); - - // construct the select instruction and return it. - return SelectInst::Create(Cond, TSI, FSI); - } - } - // (zext A) udiv (zext B) --> zext (A udiv B) if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0)) if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy())) @@ -788,6 +869,37 @@ Instruction *InstCombiner::visitUDiv(BinaryOperator &I) { I.isExact()), I.getType()); + // (LHS udiv (select (select (...)))) -> (LHS >> (select (select (...)))) + SmallVector<UDivFoldAction, 6> UDivActions; + if (visitUDivOperand(Op0, Op1, I, UDivActions)) + for (unsigned i = 0, e = UDivActions.size(); i != e; ++i) { + FoldUDivOperandCb Action = UDivActions[i].FoldAction; + Value *ActionOp1 = UDivActions[i].OperandToFold; + Instruction *Inst; + if (Action) + Inst = Action(Op0, ActionOp1, I, *this); + else { + // This action joins two actions together. The RHS of this action is + // simply the last action we processed, we saved the LHS action index in + // the joining action. + size_t SelectRHSIdx = i - 1; + Value *SelectRHS = UDivActions[SelectRHSIdx].FoldResult; + size_t SelectLHSIdx = UDivActions[i].SelectLHSIdx; + Value *SelectLHS = UDivActions[SelectLHSIdx].FoldResult; + Inst = SelectInst::Create(cast<SelectInst>(ActionOp1)->getCondition(), + SelectLHS, SelectRHS); + } + + // If this is the last action to process, return it to the InstCombiner. + // Otherwise, we insert it before the UDiv and record it so that we may + // use it as part of a joining action (i.e., a SelectInst). + if (e - i != 1) { + Inst->insertBefore(&I); + UDivActions[i].FoldResult = Inst; + } else + return Inst; + } + return 0; } @@ -858,7 +970,7 @@ static Instruction *CvtFDivConstToReciprocal(Value *Dividend, APFloat Reciprocal(FpVal.getSemantics()); bool Cvt = FpVal.getExactInverse(&Reciprocal); - if (!Cvt && AllowReciprocal && FpVal.isNormal()) { + if (!Cvt && AllowReciprocal && FpVal.isFiniteNonZero()) { Reciprocal = APFloat(FpVal.getSemantics(), 1.0f); (void)Reciprocal.divide(FpVal, APFloat::rmNearestTiesToEven); Cvt = !Reciprocal.isDenormal(); @@ -878,10 +990,19 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) { if (Value *V = SimplifyFDivInst(Op0, Op1, TD)) return ReplaceInstUsesWith(I, V); + if (isa<Constant>(Op0)) + if (SelectInst *SI = dyn_cast<SelectInst>(Op1)) + if (Instruction *R = FoldOpIntoSelect(I, SI)) + return R; + bool AllowReassociate = I.hasUnsafeAlgebra(); bool AllowReciprocal = I.hasAllowReciprocal(); if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) { + if (SelectInst *SI = dyn_cast<SelectInst>(Op0)) + if (Instruction *R = FoldOpIntoSelect(I, SI)) + return R; + if (AllowReassociate) { ConstantFP *C1 = 0; ConstantFP *C2 = Op1C; @@ -893,14 +1014,14 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) { // Constant *C = ConstantExpr::getFDiv(C1, C2); const APFloat &F = cast<ConstantFP>(C)->getValueAPF(); - if (F.isNormal() && !F.isDenormal()) + if (F.isNormal()) Res = BinaryOperator::CreateFMul(X, C); } else if (match(Op0, m_FDiv(m_Value(X), m_ConstantFP(C1)))) { // (X/C1)/C2 => X /(C2*C1) [=> X * 1/(C2*C1) if reciprocal is allowed] // Constant *C = ConstantExpr::getFMul(C1, C2); const APFloat &F = cast<ConstantFP>(C)->getValueAPF(); - if (F.isNormal() && !F.isDenormal()) { + if (F.isNormal()) { Res = CvtFDivConstToReciprocal(X, cast<ConstantFP>(C), AllowReciprocal); if (!Res) @@ -941,7 +1062,7 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) { if (Fold) { const APFloat &FoldC = cast<ConstantFP>(Fold)->getValueAPF(); - if (FoldC.isNormal() && !FoldC.isDenormal()) { + if (FoldC.isNormal()) { Instruction *R = CreateDiv ? BinaryOperator::CreateFDiv(Fold, X) : BinaryOperator::CreateFMul(X, Fold); @@ -1042,6 +1163,13 @@ Instruction *InstCombiner::visitURem(BinaryOperator &I) { return BinaryOperator::CreateAnd(Op0, Add); } + // 1 urem X -> zext(X != 1) + if (match(Op0, m_One())) { + Value *Cmp = Builder->CreateICmpNE(Op1, Op0); + Value *Ext = Builder->CreateZExt(Cmp, I.getType()); + return ReplaceInstUsesWith(I, Ext); + } + return 0; } |