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Diffstat (limited to 'gnu/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp')
| -rw-r--r-- | gnu/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 1368 |
1 files changed, 0 insertions, 1368 deletions
diff --git a/gnu/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/gnu/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp deleted file mode 100644 index 7e99f3e4e50..00000000000 --- a/gnu/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ /dev/null @@ -1,1368 +0,0 @@ -//===- InstCombineMulDivRem.cpp -------------------------------------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements the visit functions for mul, fmul, sdiv, udiv, fdiv, -// srem, urem, frem. -// -//===----------------------------------------------------------------------===// - -#include "InstCombineInternal.h" -#include "llvm/ADT/APFloat.h" -#include "llvm/ADT/APInt.h" -#include "llvm/ADT/SmallVector.h" -#include "llvm/Analysis/InstructionSimplify.h" -#include "llvm/IR/BasicBlock.h" -#include "llvm/IR/Constant.h" -#include "llvm/IR/Constants.h" -#include "llvm/IR/InstrTypes.h" -#include "llvm/IR/Instruction.h" -#include "llvm/IR/Instructions.h" -#include "llvm/IR/IntrinsicInst.h" -#include "llvm/IR/Intrinsics.h" -#include "llvm/IR/Operator.h" -#include "llvm/IR/PatternMatch.h" -#include "llvm/IR/Type.h" -#include "llvm/IR/Value.h" -#include "llvm/Support/Casting.h" -#include "llvm/Support/ErrorHandling.h" -#include "llvm/Support/KnownBits.h" -#include "llvm/Transforms/InstCombine/InstCombineWorklist.h" -#include "llvm/Transforms/Utils/BuildLibCalls.h" -#include <cassert> -#include <cstddef> -#include <cstdint> -#include <utility> - -using namespace llvm; -using namespace PatternMatch; - -#define DEBUG_TYPE "instcombine" - -/// The specific integer value is used in a context where it is known to be -/// non-zero. If this allows us to simplify the computation, do so and return -/// the new operand, otherwise return null. -static Value *simplifyValueKnownNonZero(Value *V, InstCombiner &IC, - Instruction &CxtI) { - // If V has multiple uses, then we would have to do more analysis to determine - // if this is safe. For example, the use could be in dynamically unreached - // code. - if (!V->hasOneUse()) return nullptr; - - bool MadeChange = false; - - // ((1 << A) >>u B) --> (1 << (A-B)) - // Because V cannot be zero, we know that B is less than A. - Value *A = nullptr, *B = nullptr, *One = nullptr; - if (match(V, m_LShr(m_OneUse(m_Shl(m_Value(One), m_Value(A))), m_Value(B))) && - match(One, m_One())) { - A = IC.Builder.CreateSub(A, B); - return IC.Builder.CreateShl(One, A); - } - - // (PowerOfTwo >>u B) --> isExact since shifting out the result would make it - // inexact. Similarly for <<. - BinaryOperator *I = dyn_cast<BinaryOperator>(V); - if (I && I->isLogicalShift() && - IC.isKnownToBeAPowerOfTwo(I->getOperand(0), false, 0, &CxtI)) { - // We know that this is an exact/nuw shift and that the input is a - // non-zero context as well. - if (Value *V2 = simplifyValueKnownNonZero(I->getOperand(0), IC, CxtI)) { - I->setOperand(0, V2); - MadeChange = true; - } - - if (I->getOpcode() == Instruction::LShr && !I->isExact()) { - I->setIsExact(); - MadeChange = true; - } - - if (I->getOpcode() == Instruction::Shl && !I->hasNoUnsignedWrap()) { - I->setHasNoUnsignedWrap(); - MadeChange = true; - } - } - - // TODO: Lots more we could do here: - // If V is a phi node, we can call this on each of its operands. - // "select cond, X, 0" can simplify to "X". - - return MadeChange ? V : nullptr; -} - -/// A helper routine of InstCombiner::visitMul(). -/// -/// If C is a scalar/vector of known powers of 2, then this function returns -/// a new scalar/vector obtained from logBase2 of C. -/// Return a null pointer otherwise. -static Constant *getLogBase2(Type *Ty, Constant *C) { - const APInt *IVal; - if (match(C, m_APInt(IVal)) && IVal->isPowerOf2()) - return ConstantInt::get(Ty, IVal->logBase2()); - - if (!Ty->isVectorTy()) - return nullptr; - - SmallVector<Constant *, 4> Elts; - for (unsigned I = 0, E = Ty->getVectorNumElements(); I != E; ++I) { - Constant *Elt = C->getAggregateElement(I); - if (!Elt) - return nullptr; - if (isa<UndefValue>(Elt)) { - Elts.push_back(UndefValue::get(Ty->getScalarType())); - continue; - } - if (!match(Elt, m_APInt(IVal)) || !IVal->isPowerOf2()) - return nullptr; - Elts.push_back(ConstantInt::get(Ty->getScalarType(), IVal->logBase2())); - } - - return ConstantVector::get(Elts); -} - -Instruction *InstCombiner::visitMul(BinaryOperator &I) { - if (Value *V = SimplifyMulInst(I.getOperand(0), I.getOperand(1), - SQ.getWithInstruction(&I))) - return replaceInstUsesWith(I, V); - - if (SimplifyAssociativeOrCommutative(I)) - return &I; - - if (Instruction *X = foldVectorBinop(I)) - return X; - - if (Value *V = SimplifyUsingDistributiveLaws(I)) - return replaceInstUsesWith(I, V); - - // X * -1 == 0 - X - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - if (match(Op1, m_AllOnes())) { - BinaryOperator *BO = BinaryOperator::CreateNeg(Op0, I.getName()); - if (I.hasNoSignedWrap()) - BO->setHasNoSignedWrap(); - return BO; - } - - // Also allow combining multiply instructions on vectors. - { - Value *NewOp; - Constant *C1, *C2; - const APInt *IVal; - if (match(&I, m_Mul(m_Shl(m_Value(NewOp), m_Constant(C2)), - m_Constant(C1))) && - match(C1, m_APInt(IVal))) { - // ((X << C2)*C1) == (X * (C1 << C2)) - Constant *Shl = ConstantExpr::getShl(C1, C2); - BinaryOperator *Mul = cast<BinaryOperator>(I.getOperand(0)); - BinaryOperator *BO = BinaryOperator::CreateMul(NewOp, Shl); - if (I.hasNoUnsignedWrap() && Mul->hasNoUnsignedWrap()) - BO->setHasNoUnsignedWrap(); - if (I.hasNoSignedWrap() && Mul->hasNoSignedWrap() && - Shl->isNotMinSignedValue()) - BO->setHasNoSignedWrap(); - return BO; - } - - if (match(&I, m_Mul(m_Value(NewOp), m_Constant(C1)))) { - // Replace X*(2^C) with X << C, where C is either a scalar or a vector. - if (Constant *NewCst = getLogBase2(NewOp->getType(), C1)) { - BinaryOperator *Shl = BinaryOperator::CreateShl(NewOp, NewCst); - - if (I.hasNoUnsignedWrap()) - Shl->setHasNoUnsignedWrap(); - if (I.hasNoSignedWrap()) { - const APInt *V; - if (match(NewCst, m_APInt(V)) && *V != V->getBitWidth() - 1) - Shl->setHasNoSignedWrap(); - } - - return Shl; - } - } - } - - if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { - // (Y - X) * (-(2**n)) -> (X - Y) * (2**n), for positive nonzero n - // (Y + const) * (-(2**n)) -> (-constY) * (2**n), for positive nonzero n - // The "* (2**n)" thus becomes a potential shifting opportunity. - { - const APInt & Val = CI->getValue(); - const APInt &PosVal = Val.abs(); - if (Val.isNegative() && PosVal.isPowerOf2()) { - Value *X = nullptr, *Y = nullptr; - if (Op0->hasOneUse()) { - ConstantInt *C1; - Value *Sub = nullptr; - if (match(Op0, m_Sub(m_Value(Y), m_Value(X)))) - Sub = Builder.CreateSub(X, Y, "suba"); - else if (match(Op0, m_Add(m_Value(Y), m_ConstantInt(C1)))) - Sub = Builder.CreateSub(Builder.CreateNeg(C1), Y, "subc"); - if (Sub) - return - BinaryOperator::CreateMul(Sub, - ConstantInt::get(Y->getType(), PosVal)); - } - } - } - } - - if (Instruction *FoldedMul = foldBinOpIntoSelectOrPhi(I)) - return FoldedMul; - - // Simplify mul instructions with a constant RHS. - if (isa<Constant>(Op1)) { - // Canonicalize (X+C1)*CI -> X*CI+C1*CI. - Value *X; - Constant *C1; - if (match(Op0, m_OneUse(m_Add(m_Value(X), m_Constant(C1))))) { - Value *Mul = Builder.CreateMul(C1, Op1); - // Only go forward with the transform if C1*CI simplifies to a tidier - // constant. - if (!match(Mul, m_Mul(m_Value(), m_Value()))) - return BinaryOperator::CreateAdd(Builder.CreateMul(X, Op1), Mul); - } - } - - // -X * C --> X * -C - Value *X, *Y; - Constant *Op1C; - if (match(Op0, m_Neg(m_Value(X))) && match(Op1, m_Constant(Op1C))) - return BinaryOperator::CreateMul(X, ConstantExpr::getNeg(Op1C)); - - // -X * -Y --> X * Y - if (match(Op0, m_Neg(m_Value(X))) && match(Op1, m_Neg(m_Value(Y)))) { - auto *NewMul = BinaryOperator::CreateMul(X, Y); - if (I.hasNoSignedWrap() && - cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap() && - cast<OverflowingBinaryOperator>(Op1)->hasNoSignedWrap()) - NewMul->setHasNoSignedWrap(); - return NewMul; - } - - // -X * Y --> -(X * Y) - // X * -Y --> -(X * Y) - if (match(&I, m_c_Mul(m_OneUse(m_Neg(m_Value(X))), m_Value(Y)))) - return BinaryOperator::CreateNeg(Builder.CreateMul(X, Y)); - - // (X / Y) * Y = X - (X % Y) - // (X / Y) * -Y = (X % Y) - X - { - Value *Y = Op1; - BinaryOperator *Div = dyn_cast<BinaryOperator>(Op0); - if (!Div || (Div->getOpcode() != Instruction::UDiv && - Div->getOpcode() != Instruction::SDiv)) { - Y = Op0; - Div = dyn_cast<BinaryOperator>(Op1); - } - Value *Neg = dyn_castNegVal(Y); - if (Div && Div->hasOneUse() && - (Div->getOperand(1) == Y || Div->getOperand(1) == Neg) && - (Div->getOpcode() == Instruction::UDiv || - Div->getOpcode() == Instruction::SDiv)) { - Value *X = Div->getOperand(0), *DivOp1 = Div->getOperand(1); - - // If the division is exact, X % Y is zero, so we end up with X or -X. - if (Div->isExact()) { - if (DivOp1 == Y) - return replaceInstUsesWith(I, X); - return BinaryOperator::CreateNeg(X); - } - - auto RemOpc = Div->getOpcode() == Instruction::UDiv ? Instruction::URem - : Instruction::SRem; - Value *Rem = Builder.CreateBinOp(RemOpc, X, DivOp1); - if (DivOp1 == Y) - return BinaryOperator::CreateSub(X, Rem); - return BinaryOperator::CreateSub(Rem, X); - } - } - - /// i1 mul -> i1 and. - if (I.getType()->isIntOrIntVectorTy(1)) - return BinaryOperator::CreateAnd(Op0, Op1); - - // X*(1 << Y) --> X << Y - // (1 << Y)*X --> X << Y - { - Value *Y; - BinaryOperator *BO = nullptr; - bool ShlNSW = false; - if (match(Op0, m_Shl(m_One(), m_Value(Y)))) { - BO = BinaryOperator::CreateShl(Op1, Y); - ShlNSW = cast<ShlOperator>(Op0)->hasNoSignedWrap(); - } else if (match(Op1, m_Shl(m_One(), m_Value(Y)))) { - BO = BinaryOperator::CreateShl(Op0, Y); - ShlNSW = cast<ShlOperator>(Op1)->hasNoSignedWrap(); - } - if (BO) { - if (I.hasNoUnsignedWrap()) - BO->setHasNoUnsignedWrap(); - if (I.hasNoSignedWrap() && ShlNSW) - BO->setHasNoSignedWrap(); - return BO; - } - } - - // (bool X) * Y --> X ? Y : 0 - // Y * (bool X) --> X ? Y : 0 - if (match(Op0, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) - return SelectInst::Create(X, Op1, ConstantInt::get(I.getType(), 0)); - if (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) - return SelectInst::Create(X, Op0, ConstantInt::get(I.getType(), 0)); - - // (lshr X, 31) * Y --> (ashr X, 31) & Y - // Y * (lshr X, 31) --> (ashr X, 31) & Y - // TODO: We are not checking one-use because the elimination of the multiply - // is better for analysis? - // TODO: Should we canonicalize to '(X < 0) ? Y : 0' instead? That would be - // more similar to what we're doing above. - const APInt *C; - if (match(Op0, m_LShr(m_Value(X), m_APInt(C))) && *C == C->getBitWidth() - 1) - return BinaryOperator::CreateAnd(Builder.CreateAShr(X, *C), Op1); - if (match(Op1, m_LShr(m_Value(X), m_APInt(C))) && *C == C->getBitWidth() - 1) - return BinaryOperator::CreateAnd(Builder.CreateAShr(X, *C), Op0); - - if (Instruction *Ext = narrowMathIfNoOverflow(I)) - return Ext; - - bool Changed = false; - if (!I.hasNoSignedWrap() && willNotOverflowSignedMul(Op0, Op1, I)) { - Changed = true; - I.setHasNoSignedWrap(true); - } - - if (!I.hasNoUnsignedWrap() && willNotOverflowUnsignedMul(Op0, Op1, I)) { - Changed = true; - I.setHasNoUnsignedWrap(true); - } - - return Changed ? &I : nullptr; -} - -Instruction *InstCombiner::visitFMul(BinaryOperator &I) { - if (Value *V = SimplifyFMulInst(I.getOperand(0), I.getOperand(1), - I.getFastMathFlags(), - SQ.getWithInstruction(&I))) - return replaceInstUsesWith(I, V); - - if (SimplifyAssociativeOrCommutative(I)) - return &I; - - if (Instruction *X = foldVectorBinop(I)) - return X; - - if (Instruction *FoldedMul = foldBinOpIntoSelectOrPhi(I)) - return FoldedMul; - - // X * -1.0 --> -X - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - if (match(Op1, m_SpecificFP(-1.0))) - return BinaryOperator::CreateFNegFMF(Op0, &I); - - // -X * -Y --> X * Y - Value *X, *Y; - if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_FNeg(m_Value(Y)))) - return BinaryOperator::CreateFMulFMF(X, Y, &I); - - // -X * C --> X * -C - Constant *C; - if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_Constant(C))) - return BinaryOperator::CreateFMulFMF(X, ConstantExpr::getFNeg(C), &I); - - // Sink negation: -X * Y --> -(X * Y) - if (match(Op0, m_OneUse(m_FNeg(m_Value(X))))) - return BinaryOperator::CreateFNegFMF(Builder.CreateFMulFMF(X, Op1, &I), &I); - - // Sink negation: Y * -X --> -(X * Y) - if (match(Op1, m_OneUse(m_FNeg(m_Value(X))))) - return BinaryOperator::CreateFNegFMF(Builder.CreateFMulFMF(X, Op0, &I), &I); - - // fabs(X) * fabs(X) -> X * X - if (Op0 == Op1 && match(Op0, m_Intrinsic<Intrinsic::fabs>(m_Value(X)))) - return BinaryOperator::CreateFMulFMF(X, X, &I); - - // (select A, B, C) * (select A, D, E) --> select A, (B*D), (C*E) - if (Value *V = SimplifySelectsFeedingBinaryOp(I, Op0, Op1)) - return replaceInstUsesWith(I, V); - - if (I.hasAllowReassoc()) { - // Reassociate constant RHS with another constant to form constant - // expression. - if (match(Op1, m_Constant(C)) && C->isFiniteNonZeroFP()) { - Constant *C1; - if (match(Op0, m_OneUse(m_FDiv(m_Constant(C1), m_Value(X))))) { - // (C1 / X) * C --> (C * C1) / X - Constant *CC1 = ConstantExpr::getFMul(C, C1); - if (CC1->isNormalFP()) - return BinaryOperator::CreateFDivFMF(CC1, X, &I); - } - if (match(Op0, m_FDiv(m_Value(X), m_Constant(C1)))) { - // (X / C1) * C --> X * (C / C1) - Constant *CDivC1 = ConstantExpr::getFDiv(C, C1); - if (CDivC1->isNormalFP()) - return BinaryOperator::CreateFMulFMF(X, CDivC1, &I); - - // If the constant was a denormal, try reassociating differently. - // (X / C1) * C --> X / (C1 / C) - Constant *C1DivC = ConstantExpr::getFDiv(C1, C); - if (Op0->hasOneUse() && C1DivC->isNormalFP()) - return BinaryOperator::CreateFDivFMF(X, C1DivC, &I); - } - - // We do not need to match 'fadd C, X' and 'fsub X, C' because they are - // canonicalized to 'fadd X, C'. Distributing the multiply may allow - // further folds and (X * C) + C2 is 'fma'. - if (match(Op0, m_OneUse(m_FAdd(m_Value(X), m_Constant(C1))))) { - // (X + C1) * C --> (X * C) + (C * C1) - Constant *CC1 = ConstantExpr::getFMul(C, C1); - Value *XC = Builder.CreateFMulFMF(X, C, &I); - return BinaryOperator::CreateFAddFMF(XC, CC1, &I); - } - if (match(Op0, m_OneUse(m_FSub(m_Constant(C1), m_Value(X))))) { - // (C1 - X) * C --> (C * C1) - (X * C) - Constant *CC1 = ConstantExpr::getFMul(C, C1); - Value *XC = Builder.CreateFMulFMF(X, C, &I); - return BinaryOperator::CreateFSubFMF(CC1, XC, &I); - } - } - - // sqrt(X) * sqrt(Y) -> sqrt(X * Y) - // nnan disallows the possibility of returning a number if both operands are - // negative (in that case, we should return NaN). - if (I.hasNoNaNs() && - match(Op0, m_OneUse(m_Intrinsic<Intrinsic::sqrt>(m_Value(X)))) && - match(Op1, m_OneUse(m_Intrinsic<Intrinsic::sqrt>(m_Value(Y))))) { - Value *XY = Builder.CreateFMulFMF(X, Y, &I); - Value *Sqrt = Builder.CreateUnaryIntrinsic(Intrinsic::sqrt, XY, &I); - return replaceInstUsesWith(I, Sqrt); - } - - // (X*Y) * X => (X*X) * Y where Y != X - // The purpose is two-fold: - // 1) to form a power expression (of X). - // 2) potentially shorten the critical path: After transformation, the - // latency of the instruction Y is amortized by the expression of X*X, - // and therefore Y is in a "less critical" position compared to what it - // was before the transformation. - if (match(Op0, m_OneUse(m_c_FMul(m_Specific(Op1), m_Value(Y)))) && - Op1 != Y) { - Value *XX = Builder.CreateFMulFMF(Op1, Op1, &I); - return BinaryOperator::CreateFMulFMF(XX, Y, &I); - } - if (match(Op1, m_OneUse(m_c_FMul(m_Specific(Op0), m_Value(Y)))) && - Op0 != Y) { - Value *XX = Builder.CreateFMulFMF(Op0, Op0, &I); - return BinaryOperator::CreateFMulFMF(XX, Y, &I); - } - } - - // log2(X * 0.5) * Y = log2(X) * Y - Y - if (I.isFast()) { - IntrinsicInst *Log2 = nullptr; - if (match(Op0, m_OneUse(m_Intrinsic<Intrinsic::log2>( - m_OneUse(m_FMul(m_Value(X), m_SpecificFP(0.5))))))) { - Log2 = cast<IntrinsicInst>(Op0); - Y = Op1; - } - if (match(Op1, m_OneUse(m_Intrinsic<Intrinsic::log2>( - m_OneUse(m_FMul(m_Value(X), m_SpecificFP(0.5))))))) { - Log2 = cast<IntrinsicInst>(Op1); - Y = Op0; - } - if (Log2) { - Log2->setArgOperand(0, X); - Log2->copyFastMathFlags(&I); - Value *LogXTimesY = Builder.CreateFMulFMF(Log2, Y, &I); - return BinaryOperator::CreateFSubFMF(LogXTimesY, Y, &I); - } - } - - return nullptr; -} - -/// Fold a divide or remainder with a select instruction divisor when one of the -/// select operands is zero. In that case, we can use the other select operand -/// because div/rem by zero is undefined. -bool InstCombiner::simplifyDivRemOfSelectWithZeroOp(BinaryOperator &I) { - SelectInst *SI = dyn_cast<SelectInst>(I.getOperand(1)); - if (!SI) - return false; - - int NonNullOperand; - if (match(SI->getTrueValue(), m_Zero())) - // div/rem X, (Cond ? 0 : Y) -> div/rem X, Y - NonNullOperand = 2; - else if (match(SI->getFalseValue(), m_Zero())) - // div/rem X, (Cond ? Y : 0) -> div/rem X, Y - NonNullOperand = 1; - else - return false; - - // Change the div/rem to use 'Y' instead of the select. - I.setOperand(1, SI->getOperand(NonNullOperand)); - - // Okay, we know we replace the operand of the div/rem with 'Y' with no - // problem. However, the select, or the condition of the select may have - // multiple uses. Based on our knowledge that the operand must be non-zero, - // propagate the known value for the select into other uses of it, and - // propagate a known value of the condition into its other users. - - // If the select and condition only have a single use, don't bother with this, - // early exit. - Value *SelectCond = SI->getCondition(); - if (SI->use_empty() && SelectCond->hasOneUse()) - return true; - - // Scan the current block backward, looking for other uses of SI. - BasicBlock::iterator BBI = I.getIterator(), BBFront = I.getParent()->begin(); - Type *CondTy = SelectCond->getType(); - while (BBI != BBFront) { - --BBI; - // If we found an instruction that we can't assume will return, so - // information from below it cannot be propagated above it. - if (!isGuaranteedToTransferExecutionToSuccessor(&*BBI)) - break; - - // Replace uses of the select or its condition with the known values. - for (Instruction::op_iterator I = BBI->op_begin(), E = BBI->op_end(); - I != E; ++I) { - if (*I == SI) { - *I = SI->getOperand(NonNullOperand); - Worklist.Add(&*BBI); - } else if (*I == SelectCond) { - *I = NonNullOperand == 1 ? ConstantInt::getTrue(CondTy) - : ConstantInt::getFalse(CondTy); - Worklist.Add(&*BBI); - } - } - - // If we past the instruction, quit looking for it. - if (&*BBI == SI) - SI = nullptr; - if (&*BBI == SelectCond) - SelectCond = nullptr; - - // If we ran out of things to eliminate, break out of the loop. - if (!SelectCond && !SI) - break; - - } - return true; -} - -/// True if the multiply can not be expressed in an int this size. -static bool multiplyOverflows(const APInt &C1, const APInt &C2, APInt &Product, - bool IsSigned) { - bool Overflow; - Product = IsSigned ? C1.smul_ov(C2, Overflow) : C1.umul_ov(C2, Overflow); - return Overflow; -} - -/// True if C1 is a multiple of C2. Quotient contains C1/C2. -static bool isMultiple(const APInt &C1, const APInt &C2, APInt &Quotient, - bool IsSigned) { - assert(C1.getBitWidth() == C2.getBitWidth() && "Constant widths not equal"); - - // Bail if we will divide by zero. - if (C2.isNullValue()) - return false; - - // Bail if we would divide INT_MIN by -1. - if (IsSigned && C1.isMinSignedValue() && C2.isAllOnesValue()) - return false; - - APInt Remainder(C1.getBitWidth(), /*Val=*/0ULL, IsSigned); - if (IsSigned) - APInt::sdivrem(C1, C2, Quotient, Remainder); - else - APInt::udivrem(C1, C2, Quotient, Remainder); - - return Remainder.isMinValue(); -} - -/// This function implements the transforms common to both integer division -/// instructions (udiv and sdiv). It is called by the visitors to those integer -/// division instructions. -/// Common integer divide transforms -Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) { - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - bool IsSigned = I.getOpcode() == Instruction::SDiv; - Type *Ty = I.getType(); - - // The RHS is known non-zero. - if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this, I)) { - I.setOperand(1, V); - return &I; - } - - // Handle cases involving: [su]div X, (select Cond, Y, Z) - // This does not apply for fdiv. - if (simplifyDivRemOfSelectWithZeroOp(I)) - return &I; - - const APInt *C2; - if (match(Op1, m_APInt(C2))) { - Value *X; - const APInt *C1; - - // (X / C1) / C2 -> X / (C1*C2) - if ((IsSigned && match(Op0, m_SDiv(m_Value(X), m_APInt(C1)))) || - (!IsSigned && match(Op0, m_UDiv(m_Value(X), m_APInt(C1))))) { - APInt Product(C1->getBitWidth(), /*Val=*/0ULL, IsSigned); - if (!multiplyOverflows(*C1, *C2, Product, IsSigned)) - return BinaryOperator::Create(I.getOpcode(), X, - ConstantInt::get(Ty, Product)); - } - - if ((IsSigned && match(Op0, m_NSWMul(m_Value(X), m_APInt(C1)))) || - (!IsSigned && match(Op0, m_NUWMul(m_Value(X), m_APInt(C1))))) { - APInt Quotient(C1->getBitWidth(), /*Val=*/0ULL, IsSigned); - - // (X * C1) / C2 -> X / (C2 / C1) if C2 is a multiple of C1. - if (isMultiple(*C2, *C1, Quotient, IsSigned)) { - auto *NewDiv = BinaryOperator::Create(I.getOpcode(), X, - ConstantInt::get(Ty, Quotient)); - NewDiv->setIsExact(I.isExact()); - return NewDiv; - } - - // (X * C1) / C2 -> X * (C1 / C2) if C1 is a multiple of C2. - if (isMultiple(*C1, *C2, Quotient, IsSigned)) { - auto *Mul = BinaryOperator::Create(Instruction::Mul, X, - ConstantInt::get(Ty, Quotient)); - auto *OBO = cast<OverflowingBinaryOperator>(Op0); - Mul->setHasNoUnsignedWrap(!IsSigned && OBO->hasNoUnsignedWrap()); - Mul->setHasNoSignedWrap(OBO->hasNoSignedWrap()); - return Mul; - } - } - - if ((IsSigned && match(Op0, m_NSWShl(m_Value(X), m_APInt(C1))) && - *C1 != C1->getBitWidth() - 1) || - (!IsSigned && match(Op0, m_NUWShl(m_Value(X), m_APInt(C1))))) { - APInt Quotient(C1->getBitWidth(), /*Val=*/0ULL, IsSigned); - APInt C1Shifted = APInt::getOneBitSet( - C1->getBitWidth(), static_cast<unsigned>(C1->getLimitedValue())); - - // (X << C1) / C2 -> X / (C2 >> C1) if C2 is a multiple of 1 << C1. - if (isMultiple(*C2, C1Shifted, Quotient, IsSigned)) { - auto *BO = BinaryOperator::Create(I.getOpcode(), X, - ConstantInt::get(Ty, Quotient)); - BO->setIsExact(I.isExact()); - return BO; - } - - // (X << C1) / C2 -> X * ((1 << C1) / C2) if 1 << C1 is a multiple of C2. - if (isMultiple(C1Shifted, *C2, Quotient, IsSigned)) { - auto *Mul = BinaryOperator::Create(Instruction::Mul, X, - ConstantInt::get(Ty, Quotient)); - auto *OBO = cast<OverflowingBinaryOperator>(Op0); - Mul->setHasNoUnsignedWrap(!IsSigned && OBO->hasNoUnsignedWrap()); - Mul->setHasNoSignedWrap(OBO->hasNoSignedWrap()); - return Mul; - } - } - - if (!C2->isNullValue()) // avoid X udiv 0 - if (Instruction *FoldedDiv = foldBinOpIntoSelectOrPhi(I)) - return FoldedDiv; - } - - if (match(Op0, m_One())) { - assert(!Ty->isIntOrIntVectorTy(1) && "i1 divide not removed?"); - if (IsSigned) { - // If Op1 is 0 then it's undefined behaviour, if Op1 is 1 then the - // result is one, if Op1 is -1 then the result is minus one, otherwise - // it's zero. - Value *Inc = Builder.CreateAdd(Op1, Op0); - Value *Cmp = Builder.CreateICmpULT(Inc, ConstantInt::get(Ty, 3)); - return SelectInst::Create(Cmp, Op1, ConstantInt::get(Ty, 0)); - } else { - // If Op1 is 0 then it's undefined behaviour. If Op1 is 1 then the - // result is one, otherwise it's zero. - return new ZExtInst(Builder.CreateICmpEQ(Op1, Op0), Ty); - } - } - - // See if we can fold away this div instruction. - if (SimplifyDemandedInstructionBits(I)) - return &I; - - // (X - (X rem Y)) / Y -> X / Y; usually originates as ((X / Y) * Y) / Y - Value *X, *Z; - if (match(Op0, m_Sub(m_Value(X), m_Value(Z)))) // (X - Z) / Y; Y = Op1 - if ((IsSigned && match(Z, m_SRem(m_Specific(X), m_Specific(Op1)))) || - (!IsSigned && match(Z, m_URem(m_Specific(X), m_Specific(Op1))))) - return BinaryOperator::Create(I.getOpcode(), X, Op1); - - // (X << Y) / X -> 1 << Y - Value *Y; - if (IsSigned && match(Op0, m_NSWShl(m_Specific(Op1), m_Value(Y)))) - return BinaryOperator::CreateNSWShl(ConstantInt::get(Ty, 1), Y); - if (!IsSigned && match(Op0, m_NUWShl(m_Specific(Op1), m_Value(Y)))) - return BinaryOperator::CreateNUWShl(ConstantInt::get(Ty, 1), Y); - - // X / (X * Y) -> 1 / Y if the multiplication does not overflow. - if (match(Op1, m_c_Mul(m_Specific(Op0), m_Value(Y)))) { - bool HasNSW = cast<OverflowingBinaryOperator>(Op1)->hasNoSignedWrap(); - bool HasNUW = cast<OverflowingBinaryOperator>(Op1)->hasNoUnsignedWrap(); - if ((IsSigned && HasNSW) || (!IsSigned && HasNUW)) { - I.setOperand(0, ConstantInt::get(Ty, 1)); - I.setOperand(1, Y); - return &I; - } - } - - return nullptr; -} - -static const unsigned MaxDepth = 6; - -namespace { - -using FoldUDivOperandCb = Instruction *(*)(Value *Op0, Value *Op1, - const BinaryOperator &I, - InstCombiner &IC); - -/// Used to maintain state for visitUDivOperand(). -struct UDivFoldAction { - /// Informs visitUDiv() how to fold this operand. This can be zero if this - /// action joins two actions together. - FoldUDivOperandCb FoldAction; - - /// Which operand to fold. - Value *OperandToFold; - - union { - /// The instruction returned when FoldAction is invoked. - Instruction *FoldResult; - - /// Stores the LHS action index if this action joins two actions together. - size_t SelectLHSIdx; - }; - - UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand) - : FoldAction(FA), OperandToFold(InputOperand), FoldResult(nullptr) {} - UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand, size_t SLHS) - : FoldAction(FA), OperandToFold(InputOperand), SelectLHSIdx(SLHS) {} -}; - -} // end anonymous namespace - -// X udiv 2^C -> X >> C -static Instruction *foldUDivPow2Cst(Value *Op0, Value *Op1, - const BinaryOperator &I, InstCombiner &IC) { - Constant *C1 = getLogBase2(Op0->getType(), cast<Constant>(Op1)); - if (!C1) - llvm_unreachable("Failed to constant fold udiv -> logbase2"); - BinaryOperator *LShr = BinaryOperator::CreateLShr(Op0, C1); - if (I.isExact()) - LShr->setIsExact(); - return LShr; -} - -// X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2) -// X udiv (zext (C1 << N)), where C1 is "1<<C2" --> X >> (N+C2) -static Instruction *foldUDivShl(Value *Op0, Value *Op1, const BinaryOperator &I, - InstCombiner &IC) { - Value *ShiftLeft; - if (!match(Op1, m_ZExt(m_Value(ShiftLeft)))) - ShiftLeft = Op1; - - Constant *CI; - Value *N; - if (!match(ShiftLeft, m_Shl(m_Constant(CI), m_Value(N)))) - llvm_unreachable("match should never fail here!"); - Constant *Log2Base = getLogBase2(N->getType(), CI); - if (!Log2Base) - llvm_unreachable("getLogBase2 should never fail here!"); - N = IC.Builder.CreateAdd(N, Log2Base); - if (Op1 != ShiftLeft) - N = IC.Builder.CreateZExt(N, Op1->getType()); - BinaryOperator *LShr = BinaryOperator::CreateLShr(Op0, N); - if (I.isExact()) - LShr->setIsExact(); - return LShr; -} - -// 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(); - } - - // 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, Depth)) - if (visitUDivOperand(Op0, SI->getOperand(2), I, Actions, Depth)) { - Actions.push_back(UDivFoldAction(nullptr, Op1, LHSIdx - 1)); - return Actions.size(); - } - - return 0; -} - -/// If we have zero-extended operands of an unsigned div or rem, we may be able -/// to narrow the operation (sink the zext below the math). -static Instruction *narrowUDivURem(BinaryOperator &I, - InstCombiner::BuilderTy &Builder) { - Instruction::BinaryOps Opcode = I.getOpcode(); - Value *N = I.getOperand(0); - Value *D = I.getOperand(1); - Type *Ty = I.getType(); - Value *X, *Y; - if (match(N, m_ZExt(m_Value(X))) && match(D, m_ZExt(m_Value(Y))) && - X->getType() == Y->getType() && (N->hasOneUse() || D->hasOneUse())) { - // udiv (zext X), (zext Y) --> zext (udiv X, Y) - // urem (zext X), (zext Y) --> zext (urem X, Y) - Value *NarrowOp = Builder.CreateBinOp(Opcode, X, Y); - return new ZExtInst(NarrowOp, Ty); - } - - Constant *C; - if ((match(N, m_OneUse(m_ZExt(m_Value(X)))) && match(D, m_Constant(C))) || - (match(D, m_OneUse(m_ZExt(m_Value(X)))) && match(N, m_Constant(C)))) { - // If the constant is the same in the smaller type, use the narrow version. - Constant *TruncC = ConstantExpr::getTrunc(C, X->getType()); - if (ConstantExpr::getZExt(TruncC, Ty) != C) - return nullptr; - - // udiv (zext X), C --> zext (udiv X, C') - // urem (zext X), C --> zext (urem X, C') - // udiv C, (zext X) --> zext (udiv C', X) - // urem C, (zext X) --> zext (urem C', X) - Value *NarrowOp = isa<Constant>(D) ? Builder.CreateBinOp(Opcode, X, TruncC) - : Builder.CreateBinOp(Opcode, TruncC, X); - return new ZExtInst(NarrowOp, Ty); - } - - return nullptr; -} - -Instruction *InstCombiner::visitUDiv(BinaryOperator &I) { - if (Value *V = SimplifyUDivInst(I.getOperand(0), I.getOperand(1), - SQ.getWithInstruction(&I))) - return replaceInstUsesWith(I, V); - - if (Instruction *X = foldVectorBinop(I)) - return X; - - // Handle the integer div common cases - if (Instruction *Common = commonIDivTransforms(I)) - return Common; - - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - Value *X; - const APInt *C1, *C2; - if (match(Op0, m_LShr(m_Value(X), m_APInt(C1))) && match(Op1, m_APInt(C2))) { - // (X lshr C1) udiv C2 --> X udiv (C2 << C1) - bool Overflow; - APInt C2ShlC1 = C2->ushl_ov(*C1, Overflow); - if (!Overflow) { - bool IsExact = I.isExact() && match(Op0, m_Exact(m_Value())); - BinaryOperator *BO = BinaryOperator::CreateUDiv( - X, ConstantInt::get(X->getType(), C2ShlC1)); - if (IsExact) - BO->setIsExact(); - return BO; - } - } - - // Op0 / C where C is large (negative) --> zext (Op0 >= C) - // TODO: Could use isKnownNegative() to handle non-constant values. - Type *Ty = I.getType(); - if (match(Op1, m_Negative())) { - Value *Cmp = Builder.CreateICmpUGE(Op0, Op1); - return CastInst::CreateZExtOrBitCast(Cmp, Ty); - } - // Op0 / (sext i1 X) --> zext (Op0 == -1) (if X is 0, the div is undefined) - if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) { - Value *Cmp = Builder.CreateICmpEQ(Op0, ConstantInt::getAllOnesValue(Ty)); - return CastInst::CreateZExtOrBitCast(Cmp, Ty); - } - - if (Instruction *NarrowDiv = narrowUDivURem(I, Builder)) - return NarrowDiv; - - // If the udiv operands are non-overflowing multiplies with a common operand, - // then eliminate the common factor: - // (A * B) / (A * X) --> B / X (and commuted variants) - // TODO: The code would be reduced if we had m_c_NUWMul pattern matching. - // TODO: If -reassociation handled this generally, we could remove this. - Value *A, *B; - if (match(Op0, m_NUWMul(m_Value(A), m_Value(B)))) { - if (match(Op1, m_NUWMul(m_Specific(A), m_Value(X))) || - match(Op1, m_NUWMul(m_Value(X), m_Specific(A)))) - return BinaryOperator::CreateUDiv(B, X); - if (match(Op1, m_NUWMul(m_Specific(B), m_Value(X))) || - match(Op1, m_NUWMul(m_Value(X), m_Specific(B)))) - return BinaryOperator::CreateUDiv(A, X); - } - - // (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 nullptr; -} - -Instruction *InstCombiner::visitSDiv(BinaryOperator &I) { - if (Value *V = SimplifySDivInst(I.getOperand(0), I.getOperand(1), - SQ.getWithInstruction(&I))) - return replaceInstUsesWith(I, V); - - if (Instruction *X = foldVectorBinop(I)) - return X; - - // Handle the integer div common cases - if (Instruction *Common = commonIDivTransforms(I)) - return Common; - - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - Value *X; - // sdiv Op0, -1 --> -Op0 - // sdiv Op0, (sext i1 X) --> -Op0 (because if X is 0, the op is undefined) - if (match(Op1, m_AllOnes()) || - (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))) - return BinaryOperator::CreateNeg(Op0); - - const APInt *Op1C; - if (match(Op1, m_APInt(Op1C))) { - // sdiv exact X, C --> ashr exact X, log2(C) - if (I.isExact() && Op1C->isNonNegative() && Op1C->isPowerOf2()) { - Value *ShAmt = ConstantInt::get(Op1->getType(), Op1C->exactLogBase2()); - return BinaryOperator::CreateExactAShr(Op0, ShAmt, I.getName()); - } - - // If the dividend is sign-extended and the constant divisor is small enough - // to fit in the source type, shrink the division to the narrower type: - // (sext X) sdiv C --> sext (X sdiv C) - Value *Op0Src; - if (match(Op0, m_OneUse(m_SExt(m_Value(Op0Src)))) && - Op0Src->getType()->getScalarSizeInBits() >= Op1C->getMinSignedBits()) { - - // In the general case, we need to make sure that the dividend is not the - // minimum signed value because dividing that by -1 is UB. But here, we - // know that the -1 divisor case is already handled above. - - Constant *NarrowDivisor = - ConstantExpr::getTrunc(cast<Constant>(Op1), Op0Src->getType()); - Value *NarrowOp = Builder.CreateSDiv(Op0Src, NarrowDivisor); - return new SExtInst(NarrowOp, Op0->getType()); - } - } - - if (Constant *RHS = dyn_cast<Constant>(Op1)) { - // X/INT_MIN -> X == INT_MIN - if (RHS->isMinSignedValue()) - return new ZExtInst(Builder.CreateICmpEQ(Op0, Op1), I.getType()); - - // -X/C --> X/-C provided the negation doesn't overflow. - Value *X; - if (match(Op0, m_NSWSub(m_Zero(), m_Value(X)))) { - auto *BO = BinaryOperator::CreateSDiv(X, ConstantExpr::getNeg(RHS)); - BO->setIsExact(I.isExact()); - return BO; - } - } - - // If the sign bits of both operands are zero (i.e. we can prove they are - // unsigned inputs), turn this into a udiv. - APInt Mask(APInt::getSignMask(I.getType()->getScalarSizeInBits())); - if (MaskedValueIsZero(Op0, Mask, 0, &I)) { - if (MaskedValueIsZero(Op1, Mask, 0, &I)) { - // X sdiv Y -> X udiv Y, iff X and Y don't have sign bit set - auto *BO = BinaryOperator::CreateUDiv(Op0, Op1, I.getName()); - BO->setIsExact(I.isExact()); - return BO; - } - - if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/ true, 0, &I)) { - // X sdiv (1 << Y) -> X udiv (1 << Y) ( -> X u>> Y) - // Safe because the only negative value (1 << Y) can take on is - // INT_MIN, and X sdiv INT_MIN == X udiv INT_MIN == 0 if X doesn't have - // the sign bit set. - auto *BO = BinaryOperator::CreateUDiv(Op0, Op1, I.getName()); - BO->setIsExact(I.isExact()); - return BO; - } - } - - return nullptr; -} - -/// Remove negation and try to convert division into multiplication. -static Instruction *foldFDivConstantDivisor(BinaryOperator &I) { - Constant *C; - if (!match(I.getOperand(1), m_Constant(C))) - return nullptr; - - // -X / C --> X / -C - Value *X; - if (match(I.getOperand(0), m_FNeg(m_Value(X)))) - return BinaryOperator::CreateFDivFMF(X, ConstantExpr::getFNeg(C), &I); - - // If the constant divisor has an exact inverse, this is always safe. If not, - // then we can still create a reciprocal if fast-math-flags allow it and the - // constant is a regular number (not zero, infinite, or denormal). - if (!(C->hasExactInverseFP() || (I.hasAllowReciprocal() && C->isNormalFP()))) - return nullptr; - - // Disallow denormal constants because we don't know what would happen - // on all targets. - // TODO: Use Intrinsic::canonicalize or let function attributes tell us that - // denorms are flushed? - auto *RecipC = ConstantExpr::getFDiv(ConstantFP::get(I.getType(), 1.0), C); - if (!RecipC->isNormalFP()) - return nullptr; - - // X / C --> X * (1 / C) - return BinaryOperator::CreateFMulFMF(I.getOperand(0), RecipC, &I); -} - -/// Remove negation and try to reassociate constant math. -static Instruction *foldFDivConstantDividend(BinaryOperator &I) { - Constant *C; - if (!match(I.getOperand(0), m_Constant(C))) - return nullptr; - - // C / -X --> -C / X - Value *X; - if (match(I.getOperand(1), m_FNeg(m_Value(X)))) - return BinaryOperator::CreateFDivFMF(ConstantExpr::getFNeg(C), X, &I); - - if (!I.hasAllowReassoc() || !I.hasAllowReciprocal()) - return nullptr; - - // Try to reassociate C / X expressions where X includes another constant. - Constant *C2, *NewC = nullptr; - if (match(I.getOperand(1), m_FMul(m_Value(X), m_Constant(C2)))) { - // C / (X * C2) --> (C / C2) / X - NewC = ConstantExpr::getFDiv(C, C2); - } else if (match(I.getOperand(1), m_FDiv(m_Value(X), m_Constant(C2)))) { - // C / (X / C2) --> (C * C2) / X - NewC = ConstantExpr::getFMul(C, C2); - } - // Disallow denormal constants because we don't know what would happen - // on all targets. - // TODO: Use Intrinsic::canonicalize or let function attributes tell us that - // denorms are flushed? - if (!NewC || !NewC->isNormalFP()) - return nullptr; - - return BinaryOperator::CreateFDivFMF(NewC, X, &I); -} - -Instruction *InstCombiner::visitFDiv(BinaryOperator &I) { - if (Value *V = SimplifyFDivInst(I.getOperand(0), I.getOperand(1), - I.getFastMathFlags(), - SQ.getWithInstruction(&I))) - return replaceInstUsesWith(I, V); - - if (Instruction *X = foldVectorBinop(I)) - return X; - - if (Instruction *R = foldFDivConstantDivisor(I)) - return R; - - if (Instruction *R = foldFDivConstantDividend(I)) - return R; - - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - if (isa<Constant>(Op0)) - if (SelectInst *SI = dyn_cast<SelectInst>(Op1)) - if (Instruction *R = FoldOpIntoSelect(I, SI)) - return R; - - if (isa<Constant>(Op1)) - if (SelectInst *SI = dyn_cast<SelectInst>(Op0)) - if (Instruction *R = FoldOpIntoSelect(I, SI)) - return R; - - if (I.hasAllowReassoc() && I.hasAllowReciprocal()) { - Value *X, *Y; - if (match(Op0, m_OneUse(m_FDiv(m_Value(X), m_Value(Y)))) && - (!isa<Constant>(Y) || !isa<Constant>(Op1))) { - // (X / Y) / Z => X / (Y * Z) - Value *YZ = Builder.CreateFMulFMF(Y, Op1, &I); - return BinaryOperator::CreateFDivFMF(X, YZ, &I); - } - if (match(Op1, m_OneUse(m_FDiv(m_Value(X), m_Value(Y)))) && - (!isa<Constant>(Y) || !isa<Constant>(Op0))) { - // Z / (X / Y) => (Y * Z) / X - Value *YZ = Builder.CreateFMulFMF(Y, Op0, &I); - return BinaryOperator::CreateFDivFMF(YZ, X, &I); - } - } - - if (I.hasAllowReassoc() && Op0->hasOneUse() && Op1->hasOneUse()) { - // sin(X) / cos(X) -> tan(X) - // cos(X) / sin(X) -> 1/tan(X) (cotangent) - Value *X; - bool IsTan = match(Op0, m_Intrinsic<Intrinsic::sin>(m_Value(X))) && - match(Op1, m_Intrinsic<Intrinsic::cos>(m_Specific(X))); - bool IsCot = - !IsTan && match(Op0, m_Intrinsic<Intrinsic::cos>(m_Value(X))) && - match(Op1, m_Intrinsic<Intrinsic::sin>(m_Specific(X))); - - if ((IsTan || IsCot) && hasUnaryFloatFn(&TLI, I.getType(), LibFunc_tan, - LibFunc_tanf, LibFunc_tanl)) { - IRBuilder<> B(&I); - IRBuilder<>::FastMathFlagGuard FMFGuard(B); - B.setFastMathFlags(I.getFastMathFlags()); - AttributeList Attrs = CallSite(Op0).getCalledFunction()->getAttributes(); - Value *Res = emitUnaryFloatFnCall(X, &TLI, LibFunc_tan, LibFunc_tanf, - LibFunc_tanl, B, Attrs); - if (IsCot) - Res = B.CreateFDiv(ConstantFP::get(I.getType(), 1.0), Res); - return replaceInstUsesWith(I, Res); - } - } - - // -X / -Y -> X / Y - Value *X, *Y; - if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_FNeg(m_Value(Y)))) { - I.setOperand(0, X); - I.setOperand(1, Y); - return &I; - } - - // X / (X * Y) --> 1.0 / Y - // Reassociate to (X / X -> 1.0) is legal when NaNs are not allowed. - // We can ignore the possibility that X is infinity because INF/INF is NaN. - if (I.hasNoNaNs() && I.hasAllowReassoc() && - match(Op1, m_c_FMul(m_Specific(Op0), m_Value(Y)))) { - I.setOperand(0, ConstantFP::get(I.getType(), 1.0)); - I.setOperand(1, Y); - return &I; - } - - return nullptr; -} - -/// This function implements the transforms common to both integer remainder -/// instructions (urem and srem). It is called by the visitors to those integer -/// remainder instructions. -/// Common integer remainder transforms -Instruction *InstCombiner::commonIRemTransforms(BinaryOperator &I) { - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - - // The RHS is known non-zero. - if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this, I)) { - I.setOperand(1, V); - return &I; - } - - // Handle cases involving: rem X, (select Cond, Y, Z) - if (simplifyDivRemOfSelectWithZeroOp(I)) - return &I; - - if (isa<Constant>(Op1)) { - if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) { - if (SelectInst *SI = dyn_cast<SelectInst>(Op0I)) { - if (Instruction *R = FoldOpIntoSelect(I, SI)) - return R; - } else if (auto *PN = dyn_cast<PHINode>(Op0I)) { - const APInt *Op1Int; - if (match(Op1, m_APInt(Op1Int)) && !Op1Int->isMinValue() && - (I.getOpcode() == Instruction::URem || - !Op1Int->isMinSignedValue())) { - // foldOpIntoPhi will speculate instructions to the end of the PHI's - // predecessor blocks, so do this only if we know the srem or urem - // will not fault. - if (Instruction *NV = foldOpIntoPhi(I, PN)) - return NV; - } - } - - // See if we can fold away this rem instruction. - if (SimplifyDemandedInstructionBits(I)) - return &I; - } - } - - return nullptr; -} - -Instruction *InstCombiner::visitURem(BinaryOperator &I) { - if (Value *V = SimplifyURemInst(I.getOperand(0), I.getOperand(1), - SQ.getWithInstruction(&I))) - return replaceInstUsesWith(I, V); - - if (Instruction *X = foldVectorBinop(I)) - return X; - - if (Instruction *common = commonIRemTransforms(I)) - return common; - - if (Instruction *NarrowRem = narrowUDivURem(I, Builder)) - return NarrowRem; - - // X urem Y -> X and Y-1, where Y is a power of 2, - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - Type *Ty = I.getType(); - if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/ true, 0, &I)) { - Constant *N1 = Constant::getAllOnesValue(Ty); - Value *Add = Builder.CreateAdd(Op1, N1); - return BinaryOperator::CreateAnd(Op0, Add); - } - - // 1 urem X -> zext(X != 1) - if (match(Op0, m_One())) - return CastInst::CreateZExtOrBitCast(Builder.CreateICmpNE(Op1, Op0), Ty); - - // X urem C -> X < C ? X : X - C, where C >= signbit. - if (match(Op1, m_Negative())) { - Value *Cmp = Builder.CreateICmpULT(Op0, Op1); - Value *Sub = Builder.CreateSub(Op0, Op1); - return SelectInst::Create(Cmp, Op0, Sub); - } - - // If the divisor is a sext of a boolean, then the divisor must be max - // unsigned value (-1). Therefore, the remainder is Op0 unless Op0 is also - // max unsigned value. In that case, the remainder is 0: - // urem Op0, (sext i1 X) --> (Op0 == -1) ? 0 : Op0 - Value *X; - if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) { - Value *Cmp = Builder.CreateICmpEQ(Op0, ConstantInt::getAllOnesValue(Ty)); - return SelectInst::Create(Cmp, ConstantInt::getNullValue(Ty), Op0); - } - - return nullptr; -} - -Instruction *InstCombiner::visitSRem(BinaryOperator &I) { - if (Value *V = SimplifySRemInst(I.getOperand(0), I.getOperand(1), - SQ.getWithInstruction(&I))) - return replaceInstUsesWith(I, V); - - if (Instruction *X = foldVectorBinop(I)) - return X; - - // Handle the integer rem common cases - if (Instruction *Common = commonIRemTransforms(I)) - return Common; - - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - { - const APInt *Y; - // X % -Y -> X % Y - if (match(Op1, m_Negative(Y)) && !Y->isMinSignedValue()) { - Worklist.AddValue(I.getOperand(1)); - I.setOperand(1, ConstantInt::get(I.getType(), -*Y)); - return &I; - } - } - - // If the sign bits of both operands are zero (i.e. we can prove they are - // unsigned inputs), turn this into a urem. - APInt Mask(APInt::getSignMask(I.getType()->getScalarSizeInBits())); - if (MaskedValueIsZero(Op1, Mask, 0, &I) && - MaskedValueIsZero(Op0, Mask, 0, &I)) { - // X srem Y -> X urem Y, iff X and Y don't have sign bit set - return BinaryOperator::CreateURem(Op0, Op1, I.getName()); - } - - // If it's a constant vector, flip any negative values positive. - if (isa<ConstantVector>(Op1) || isa<ConstantDataVector>(Op1)) { - Constant *C = cast<Constant>(Op1); - unsigned VWidth = C->getType()->getVectorNumElements(); - - bool hasNegative = false; - bool hasMissing = false; - for (unsigned i = 0; i != VWidth; ++i) { - Constant *Elt = C->getAggregateElement(i); - if (!Elt) { - hasMissing = true; - break; - } - - if (ConstantInt *RHS = dyn_cast<ConstantInt>(Elt)) - if (RHS->isNegative()) - hasNegative = true; - } - - if (hasNegative && !hasMissing) { - SmallVector<Constant *, 16> Elts(VWidth); - for (unsigned i = 0; i != VWidth; ++i) { - Elts[i] = C->getAggregateElement(i); // Handle undef, etc. - if (ConstantInt *RHS = dyn_cast<ConstantInt>(Elts[i])) { - if (RHS->isNegative()) - Elts[i] = cast<ConstantInt>(ConstantExpr::getNeg(RHS)); - } - } - - Constant *NewRHSV = ConstantVector::get(Elts); - if (NewRHSV != C) { // Don't loop on -MININT - Worklist.AddValue(I.getOperand(1)); - I.setOperand(1, NewRHSV); - return &I; - } - } - } - - return nullptr; -} - -Instruction *InstCombiner::visitFRem(BinaryOperator &I) { - if (Value *V = SimplifyFRemInst(I.getOperand(0), I.getOperand(1), - I.getFastMathFlags(), - SQ.getWithInstruction(&I))) - return replaceInstUsesWith(I, V); - - if (Instruction *X = foldVectorBinop(I)) - return X; - - return nullptr; -} |