//
//===----------------------------------------------------------------------===//
-#include "InstCombine.h"
-#include "llvm/IntrinsicInst.h"
+#include "InstCombineInternal.h"
#include "llvm/Analysis/InstructionSimplify.h"
-#include "llvm/Support/PatternMatch.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/PatternMatch.h"
using namespace llvm;
using namespace PatternMatch;
+#define DEBUG_TYPE "instcombine"
+
/// simplifyValueKnownNonZero - 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) {
+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 0;
-
+ 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 = 0, *B = 0, *PowerOf2 = 0;
- if (match(V, m_LShr(m_OneUse(m_Shl(m_Value(PowerOf2), m_Value(A))),
- m_Value(B))) &&
- // The "1" can be any value known to be a power of 2.
- isPowerOfTwo(PowerOf2, IC.getTargetData())) {
+ 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(PowerOf2, A);
+ return IC.Builder->CreateShl(One, A);
}
-
+
// (PowerOfTwo >>u B) --> isExact since shifting out the result would make it
// inexact. Similarly for <<.
if (BinaryOperator *I = dyn_cast<BinaryOperator>(V))
if (I->isLogicalShift() &&
- isPowerOfTwo(I->getOperand(0), IC.getTargetData())) {
+ isKnownToBeAPowerOfTwo(I->getOperand(0), IC.getDataLayout(), false, 0,
+ IC.getAssumptionCache(), &CxtI,
+ IC.getDominatorTree())) {
// 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)) {
+ 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 : 0;
+
+ return MadeChange ? V : nullptr;
}
/// MultiplyOverflows - True if the multiply can not be expressed in an int
/// this size.
-static bool MultiplyOverflows(ConstantInt *C1, ConstantInt *C2, bool sign) {
- uint32_t W = C1->getBitWidth();
- APInt LHSExt = C1->getValue(), RHSExt = C2->getValue();
- if (sign) {
- LHSExt = LHSExt.sext(W * 2);
- RHSExt = RHSExt.sext(W * 2);
- } else {
- LHSExt = LHSExt.zext(W * 2);
- RHSExt = RHSExt.zext(W * 2);
- }
-
- APInt MulExt = LHSExt * RHSExt;
-
- if (!sign)
- return MulExt.ugt(APInt::getLowBitsSet(W * 2, W));
-
- APInt Min = APInt::getSignedMinValue(W).sext(W * 2);
- APInt Max = APInt::getSignedMaxValue(W).sext(W * 2);
- return MulExt.slt(Min) || MulExt.sgt(Max);
+static bool MultiplyOverflows(const APInt &C1, const APInt &C2, APInt &Product,
+ bool IsSigned) {
+ bool Overflow;
+ if (IsSigned)
+ Product = C1.smul_ov(C2, Overflow);
+ else
+ Product = C1.umul_ov(C2, Overflow);
+
+ return Overflow;
+}
+
+/// \brief True if C2 is a multiple of C1. Quotient contains C2/C1.
+static bool IsMultiple(const APInt &C1, const APInt &C2, APInt &Quotient,
+ bool IsSigned) {
+ assert(C1.getBitWidth() == C2.getBitWidth() &&
+ "Inconsistent width of constants!");
+
+ 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();
+}
+
+/// \brief A helper routine of InstCombiner::visitMul().
+///
+/// If C is a vector of known powers of 2, then this function returns
+/// a new vector obtained from C replacing each element with its logBase2.
+/// Return a null pointer otherwise.
+static Constant *getLogBase2Vector(ConstantDataVector *CV) {
+ const APInt *IVal;
+ SmallVector<Constant *, 4> Elts;
+
+ for (unsigned I = 0, E = CV->getNumElements(); I != E; ++I) {
+ Constant *Elt = CV->getElementAsConstant(I);
+ if (!match(Elt, m_APInt(IVal)) || !IVal->isPowerOf2())
+ return nullptr;
+ Elts.push_back(ConstantInt::get(Elt->getType(), IVal->logBase2()));
+ }
+
+ return ConstantVector::get(Elts);
+}
+
+/// \brief Return true if we can prove that:
+/// (mul LHS, RHS) === (mul nsw LHS, RHS)
+bool InstCombiner::WillNotOverflowSignedMul(Value *LHS, Value *RHS,
+ Instruction &CxtI) {
+ // Multiplying n * m significant bits yields a result of n + m significant
+ // bits. If the total number of significant bits does not exceed the
+ // result bit width (minus 1), there is no overflow.
+ // This means if we have enough leading sign bits in the operands
+ // we can guarantee that the result does not overflow.
+ // Ref: "Hacker's Delight" by Henry Warren
+ unsigned BitWidth = LHS->getType()->getScalarSizeInBits();
+
+ // Note that underestimating the number of sign bits gives a more
+ // conservative answer.
+ unsigned SignBits =
+ ComputeNumSignBits(LHS, 0, &CxtI) + ComputeNumSignBits(RHS, 0, &CxtI);
+
+ // First handle the easy case: if we have enough sign bits there's
+ // definitely no overflow.
+ if (SignBits > BitWidth + 1)
+ return true;
+
+ // There are two ambiguous cases where there can be no overflow:
+ // SignBits == BitWidth + 1 and
+ // SignBits == BitWidth
+ // The second case is difficult to check, therefore we only handle the
+ // first case.
+ if (SignBits == BitWidth + 1) {
+ // It overflows only when both arguments are negative and the true
+ // product is exactly the minimum negative number.
+ // E.g. mul i16 with 17 sign bits: 0xff00 * 0xff80 = 0x8000
+ // For simplicity we just check if at least one side is not negative.
+ bool LHSNonNegative, LHSNegative;
+ bool RHSNonNegative, RHSNegative;
+ ComputeSignBit(LHS, LHSNonNegative, LHSNegative, /*Depth=*/0, &CxtI);
+ ComputeSignBit(RHS, RHSNonNegative, RHSNegative, /*Depth=*/0, &CxtI);
+ if (LHSNonNegative || RHSNonNegative)
+ return true;
+ }
+ return false;
}
Instruction *InstCombiner::visitMul(BinaryOperator &I) {
bool Changed = SimplifyAssociativeOrCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifyMulInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifyMulInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
if (Value *V = SimplifyUsingDistributiveLaws(I))
return ReplaceInstUsesWith(I, V);
- if (match(Op1, m_AllOnes())) // X * -1 == 0 - X
- return BinaryOperator::CreateNeg(Op0, I.getName());
-
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
-
- // ((X << C1)*C2) == (X * (C2 << C1))
- if (BinaryOperator *SI = dyn_cast<BinaryOperator>(Op0))
- if (SI->getOpcode() == Instruction::Shl)
- if (Constant *ShOp = dyn_cast<Constant>(SI->getOperand(1)))
- return BinaryOperator::CreateMul(SI->getOperand(0),
- ConstantExpr::getShl(CI, ShOp));
-
- const APInt &Val = CI->getValue();
- if (Val.isPowerOf2()) { // Replace X*(2^C) with X << C
- Constant *NewCst = ConstantInt::get(Op0->getType(), Val.logBase2());
- BinaryOperator *Shl = BinaryOperator::CreateShl(Op0, NewCst);
- if (I.hasNoSignedWrap()) Shl->setHasNoSignedWrap();
- if (I.hasNoUnsignedWrap()) Shl->setHasNoUnsignedWrap();
- return Shl;
- }
-
- // Canonicalize (X+C1)*CI -> X*CI+C1*CI.
- { Value *X; ConstantInt *C1;
- if (Op0->hasOneUse() &&
- match(Op0, m_Add(m_Value(X), m_ConstantInt(C1)))) {
- Value *Add = Builder->CreateMul(X, CI);
- return BinaryOperator::CreateAdd(Add, Builder->CreateMul(C1, CI));
+ // X * -1 == 0 - X
+ 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)))) {
+ Constant *NewCst = nullptr;
+ if (match(C1, m_APInt(IVal)) && IVal->isPowerOf2())
+ // Replace X*(2^C) with X << C, where C is either a scalar or a splat.
+ NewCst = ConstantInt::get(NewOp->getType(), IVal->logBase2());
+ else if (ConstantDataVector *CV = dyn_cast<ConstantDataVector>(C1))
+ // Replace X*(2^C) with X << C, where C is a vector of known
+ // constant powers of 2.
+ NewCst = getLogBase2Vector(CV);
+
+ if (NewCst) {
+ unsigned Width = NewCst->getType()->getPrimitiveSizeInBits();
+ BinaryOperator *Shl = BinaryOperator::CreateShl(NewOp, NewCst);
+
+ if (I.hasNoUnsignedWrap())
+ Shl->setHasNoUnsignedWrap();
+ if (I.hasNoSignedWrap()) {
+ uint64_t V;
+ if (match(NewCst, m_ConstantInt(V)) && V != Width - 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 = 0, *Y = 0;
+ Value *X = nullptr, *Y = nullptr;
if (Op0->hasOneUse()) {
ConstantInt *C1;
- Value *Sub = 0;
+ 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))))
}
}
}
-
+
// Simplify mul instructions with a constant RHS.
- if (isa<Constant>(Op1)) {
+ if (isa<Constant>(Op1)) {
// Try to fold constant mul into select arguments.
if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
if (Instruction *R = FoldOpIntoSelect(I, SI))
if (isa<PHINode>(Op0))
if (Instruction *NV = FoldOpIntoPhi(I))
return NV;
+
+ // 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);
+ }
+ }
}
- if (Value *Op0v = dyn_castNegVal(Op0)) // -X * -Y = X*Y
- if (Value *Op1v = dyn_castNegVal(Op1))
- return BinaryOperator::CreateMul(Op0v, Op1v);
+ if (Value *Op0v = dyn_castNegVal(Op0)) { // -X * -Y = X*Y
+ if (Value *Op1v = dyn_castNegVal(Op1)) {
+ BinaryOperator *BO = BinaryOperator::CreateMul(Op0v, Op1v);
+ if (I.hasNoSignedWrap() &&
+ match(Op0, m_NSWSub(m_Value(), m_Value())) &&
+ match(Op1, m_NSWSub(m_Value(), m_Value())))
+ BO->setHasNoSignedWrap();
+ return BO;
+ }
+ }
// (X / Y) * Y = X - (X % Y)
// (X / Y) * -Y = (X % Y) - X
Value *Op1C = Op1;
BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0);
if (!BO ||
- (BO->getOpcode() != Instruction::UDiv &&
+ (BO->getOpcode() != Instruction::UDiv &&
BO->getOpcode() != Instruction::SDiv)) {
Op1C = Op0;
BO = dyn_cast<BinaryOperator>(Op1);
}
/// i1 mul -> i1 and.
- if (I.getType()->isIntegerTy(1))
+ if (I.getType()->getScalarType()->isIntegerTy(1))
return BinaryOperator::CreateAnd(Op0, Op1);
// X*(1 << Y) --> X << Y
// (1 << Y)*X --> X << Y
{
Value *Y;
- if (match(Op0, m_Shl(m_One(), m_Value(Y))))
- return BinaryOperator::CreateShl(Op1, Y);
- if (match(Op1, m_Shl(m_One(), m_Value(Y))))
- return BinaryOperator::CreateShl(Op0, 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;
+ }
}
-
+
// If one of the operands of the multiply is a cast from a boolean value, then
// we know the bool is either zero or one, so this is a 'masking' multiply.
// X * Y (where Y is 0 or 1) -> X & (0-Y)
if (!I.getType()->isVectorTy()) {
// -2 is "-1 << 1" so it is all bits set except the low one.
APInt Negative2(I.getType()->getPrimitiveSizeInBits(), (uint64_t)-2, true);
-
- Value *BoolCast = 0, *OtherOp = 0;
- if (MaskedValueIsZero(Op0, Negative2))
+
+ Value *BoolCast = nullptr, *OtherOp = nullptr;
+ if (MaskedValueIsZero(Op0, Negative2, 0, &I))
BoolCast = Op0, OtherOp = Op1;
- else if (MaskedValueIsZero(Op1, Negative2))
+ else if (MaskedValueIsZero(Op1, Negative2, 0, &I))
BoolCast = Op1, OtherOp = Op0;
if (BoolCast) {
}
}
- return Changed ? &I : 0;
+ if (!I.hasNoSignedWrap() && WillNotOverflowSignedMul(Op0, Op1, I)) {
+ Changed = true;
+ I.setHasNoSignedWrap(true);
+ }
+
+ if (!I.hasNoUnsignedWrap() &&
+ computeOverflowForUnsignedMul(Op0, Op1, &I) ==
+ OverflowResult::NeverOverflows) {
+ Changed = true;
+ I.setHasNoUnsignedWrap(true);
+ }
+
+ return Changed ? &I : nullptr;
+}
+
+/// Detect pattern log2(Y * 0.5) with corresponding fast math flags.
+static void detectLog2OfHalf(Value *&Op, Value *&Y, IntrinsicInst *&Log2) {
+ if (!Op->hasOneUse())
+ return;
+
+ IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op);
+ if (!II)
+ return;
+ if (II->getIntrinsicID() != Intrinsic::log2 || !II->hasUnsafeAlgebra())
+ return;
+ Log2 = II;
+
+ Value *OpLog2Of = II->getArgOperand(0);
+ if (!OpLog2Of->hasOneUse())
+ return;
+
+ Instruction *I = dyn_cast<Instruction>(OpLog2Of);
+ if (!I)
+ return;
+ if (I->getOpcode() != Instruction::FMul || !I->hasUnsafeAlgebra())
+ return;
+
+ if (match(I->getOperand(0), m_SpecificFP(0.5)))
+ Y = I->getOperand(1);
+ else if (match(I->getOperand(1), m_SpecificFP(0.5)))
+ Y = I->getOperand(0);
+}
+
+static bool isFiniteNonZeroFp(Constant *C) {
+ if (C->getType()->isVectorTy()) {
+ for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E;
+ ++I) {
+ ConstantFP *CFP = dyn_cast_or_null<ConstantFP>(C->getAggregateElement(I));
+ if (!CFP || !CFP->getValueAPF().isFiniteNonZero())
+ return false;
+ }
+ return true;
+ }
+
+ return isa<ConstantFP>(C) &&
+ cast<ConstantFP>(C)->getValueAPF().isFiniteNonZero();
+}
+
+static bool isNormalFp(Constant *C) {
+ if (C->getType()->isVectorTy()) {
+ for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E;
+ ++I) {
+ ConstantFP *CFP = dyn_cast_or_null<ConstantFP>(C->getAggregateElement(I));
+ if (!CFP || !CFP->getValueAPF().isNormal())
+ return false;
+ }
+ return true;
+ }
+
+ return isa<ConstantFP>(C) && cast<ConstantFP>(C)->getValueAPF().isNormal();
+}
+
+/// Helper function of InstCombiner::visitFMul(BinaryOperator(). It returns
+/// true iff the given value is FMul or FDiv with one and only one operand
+/// being a normal constant (i.e. not Zero/NaN/Infinity).
+static bool isFMulOrFDivWithConstant(Value *V) {
+ Instruction *I = dyn_cast<Instruction>(V);
+ if (!I || (I->getOpcode() != Instruction::FMul &&
+ I->getOpcode() != Instruction::FDiv))
+ return false;
+
+ Constant *C0 = dyn_cast<Constant>(I->getOperand(0));
+ Constant *C1 = dyn_cast<Constant>(I->getOperand(1));
+
+ if (C0 && C1)
+ return false;
+
+ return (C0 && isFiniteNonZeroFp(C0)) || (C1 && isFiniteNonZeroFp(C1));
+}
+
+/// foldFMulConst() is a helper routine of InstCombiner::visitFMul().
+/// The input \p FMulOrDiv is a FMul/FDiv with one and only one operand
+/// being a constant (i.e. isFMulOrFDivWithConstant(FMulOrDiv) == true).
+/// This function is to simplify "FMulOrDiv * C" and returns the
+/// resulting expression. Note that this function could return NULL in
+/// case the constants cannot be folded into a normal floating-point.
+///
+Value *InstCombiner::foldFMulConst(Instruction *FMulOrDiv, Constant *C,
+ Instruction *InsertBefore) {
+ assert(isFMulOrFDivWithConstant(FMulOrDiv) && "V is invalid");
+
+ Value *Opnd0 = FMulOrDiv->getOperand(0);
+ Value *Opnd1 = FMulOrDiv->getOperand(1);
+
+ Constant *C0 = dyn_cast<Constant>(Opnd0);
+ Constant *C1 = dyn_cast<Constant>(Opnd1);
+
+ BinaryOperator *R = nullptr;
+
+ // (X * C0) * C => X * (C0*C)
+ if (FMulOrDiv->getOpcode() == Instruction::FMul) {
+ Constant *F = ConstantExpr::getFMul(C1 ? C1 : C0, C);
+ if (isNormalFp(F))
+ R = BinaryOperator::CreateFMul(C1 ? Opnd0 : Opnd1, F);
+ } else {
+ if (C0) {
+ // (C0 / X) * C => (C0 * C) / X
+ if (FMulOrDiv->hasOneUse()) {
+ // It would otherwise introduce another div.
+ Constant *F = ConstantExpr::getFMul(C0, C);
+ if (isNormalFp(F))
+ R = BinaryOperator::CreateFDiv(F, Opnd1);
+ }
+ } else {
+ // (X / C1) * C => X * (C/C1) if C/C1 is not a denormal
+ Constant *F = ConstantExpr::getFDiv(C, C1);
+ if (isNormalFp(F)) {
+ R = BinaryOperator::CreateFMul(Opnd0, F);
+ } else {
+ // (X / C1) * C => X / (C1/C)
+ Constant *F = ConstantExpr::getFDiv(C1, C);
+ if (isNormalFp(F))
+ R = BinaryOperator::CreateFDiv(Opnd0, F);
+ }
+ }
+ }
+
+ if (R) {
+ R->setHasUnsafeAlgebra(true);
+ InsertNewInstWith(R, *InsertBefore);
+ }
+
+ return R;
}
Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
bool Changed = SimplifyAssociativeOrCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- // Simplify mul instructions with a constant RHS.
- if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
- if (ConstantFP *Op1F = dyn_cast<ConstantFP>(Op1C)) {
- // "In IEEE floating point, x*1 is not equivalent to x for nans. However,
- // ANSI says we can drop signals, so we can do this anyway." (from GCC)
- if (Op1F->isExactlyValue(1.0))
- return ReplaceInstUsesWith(I, Op0); // Eliminate 'fmul double %X, 1.0'
- } else if (ConstantDataVector *Op1V = dyn_cast<ConstantDataVector>(Op1C)) {
- // As above, vector X*splat(1.0) -> X in all defined cases.
- if (ConstantFP *F = dyn_cast_or_null<ConstantFP>(Op1V->getSplatValue()))
- if (F->isExactlyValue(1.0))
- return ReplaceInstUsesWith(I, Op0);
- }
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (isa<Constant>(Op0))
+ std::swap(Op0, Op1);
+
+ if (Value *V =
+ SimplifyFMulInst(Op0, Op1, I.getFastMathFlags(), DL, TLI, DT, AC))
+ return ReplaceInstUsesWith(I, V);
+ bool AllowReassociate = I.hasUnsafeAlgebra();
+
+ // Simplify mul instructions with a constant RHS.
+ if (isa<Constant>(Op1)) {
// Try to fold constant mul into select arguments.
if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
if (Instruction *R = FoldOpIntoSelect(I, SI))
if (isa<PHINode>(Op0))
if (Instruction *NV = FoldOpIntoPhi(I))
return NV;
+
+ // (fmul X, -1.0) --> (fsub -0.0, X)
+ if (match(Op1, m_SpecificFP(-1.0))) {
+ Constant *NegZero = ConstantFP::getNegativeZero(Op1->getType());
+ Instruction *RI = BinaryOperator::CreateFSub(NegZero, Op0);
+ RI->copyFastMathFlags(&I);
+ return RI;
+ }
+
+ Constant *C = cast<Constant>(Op1);
+ if (AllowReassociate && isFiniteNonZeroFp(C)) {
+ // Let MDC denote an expression in one of these forms:
+ // X * C, C/X, X/C, where C is a constant.
+ //
+ // Try to simplify "MDC * Constant"
+ if (isFMulOrFDivWithConstant(Op0))
+ if (Value *V = foldFMulConst(cast<Instruction>(Op0), C, &I))
+ return ReplaceInstUsesWith(I, V);
+
+ // (MDC +/- C1) * C => (MDC * C) +/- (C1 * C)
+ Instruction *FAddSub = dyn_cast<Instruction>(Op0);
+ if (FAddSub &&
+ (FAddSub->getOpcode() == Instruction::FAdd ||
+ FAddSub->getOpcode() == Instruction::FSub)) {
+ Value *Opnd0 = FAddSub->getOperand(0);
+ Value *Opnd1 = FAddSub->getOperand(1);
+ Constant *C0 = dyn_cast<Constant>(Opnd0);
+ Constant *C1 = dyn_cast<Constant>(Opnd1);
+ bool Swap = false;
+ if (C0) {
+ std::swap(C0, C1);
+ std::swap(Opnd0, Opnd1);
+ Swap = true;
+ }
+
+ if (C1 && isFiniteNonZeroFp(C1) && isFMulOrFDivWithConstant(Opnd0)) {
+ Value *M1 = ConstantExpr::getFMul(C1, C);
+ Value *M0 = isNormalFp(cast<Constant>(M1)) ?
+ foldFMulConst(cast<Instruction>(Opnd0), C, &I) :
+ nullptr;
+ if (M0 && M1) {
+ if (Swap && FAddSub->getOpcode() == Instruction::FSub)
+ std::swap(M0, M1);
+
+ Instruction *RI = (FAddSub->getOpcode() == Instruction::FAdd)
+ ? BinaryOperator::CreateFAdd(M0, M1)
+ : BinaryOperator::CreateFSub(M0, M1);
+ RI->copyFastMathFlags(&I);
+ return RI;
+ }
+ }
+ }
+ }
+ }
+
+ // sqrt(X) * sqrt(X) -> X
+ if (AllowReassociate && (Op0 == Op1))
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op0))
+ if (II->getIntrinsicID() == Intrinsic::sqrt)
+ return ReplaceInstUsesWith(I, II->getOperand(0));
+
+ // Under unsafe algebra do:
+ // X * log2(0.5*Y) = X*log2(Y) - X
+ if (AllowReassociate) {
+ Value *OpX = nullptr;
+ Value *OpY = nullptr;
+ IntrinsicInst *Log2;
+ detectLog2OfHalf(Op0, OpY, Log2);
+ if (OpY) {
+ OpX = Op1;
+ } else {
+ detectLog2OfHalf(Op1, OpY, Log2);
+ if (OpY) {
+ OpX = Op0;
+ }
+ }
+ // if pattern detected emit alternate sequence
+ if (OpX && OpY) {
+ BuilderTy::FastMathFlagGuard Guard(*Builder);
+ Builder->SetFastMathFlags(Log2->getFastMathFlags());
+ Log2->setArgOperand(0, OpY);
+ Value *FMulVal = Builder->CreateFMul(OpX, Log2);
+ Value *FSub = Builder->CreateFSub(FMulVal, OpX);
+ FSub->takeName(&I);
+ return ReplaceInstUsesWith(I, FSub);
+ }
}
- if (Value *Op0v = dyn_castFNegVal(Op0)) // -X * -Y = X*Y
- if (Value *Op1v = dyn_castFNegVal(Op1))
- return BinaryOperator::CreateFMul(Op0v, Op1v);
+ // Handle symmetric situation in a 2-iteration loop
+ Value *Opnd0 = Op0;
+ Value *Opnd1 = Op1;
+ for (int i = 0; i < 2; i++) {
+ bool IgnoreZeroSign = I.hasNoSignedZeros();
+ if (BinaryOperator::isFNeg(Opnd0, IgnoreZeroSign)) {
+ BuilderTy::FastMathFlagGuard Guard(*Builder);
+ Builder->SetFastMathFlags(I.getFastMathFlags());
+
+ Value *N0 = dyn_castFNegVal(Opnd0, IgnoreZeroSign);
+ Value *N1 = dyn_castFNegVal(Opnd1, IgnoreZeroSign);
+
+ // -X * -Y => X*Y
+ if (N1) {
+ Value *FMul = Builder->CreateFMul(N0, N1);
+ FMul->takeName(&I);
+ return ReplaceInstUsesWith(I, FMul);
+ }
- return Changed ? &I : 0;
+ if (Opnd0->hasOneUse()) {
+ // -X * Y => -(X*Y) (Promote negation as high as possible)
+ Value *T = Builder->CreateFMul(N0, Opnd1);
+ Value *Neg = Builder->CreateFNeg(T);
+ Neg->takeName(&I);
+ return ReplaceInstUsesWith(I, Neg);
+ }
+ }
+
+ // (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 (AllowReassociate) {
+ Value *Opnd0_0, *Opnd0_1;
+ if (Opnd0->hasOneUse() &&
+ match(Opnd0, m_FMul(m_Value(Opnd0_0), m_Value(Opnd0_1)))) {
+ Value *Y = nullptr;
+ if (Opnd0_0 == Opnd1 && Opnd0_1 != Opnd1)
+ Y = Opnd0_1;
+ else if (Opnd0_1 == Opnd1 && Opnd0_0 != Opnd1)
+ Y = Opnd0_0;
+
+ if (Y) {
+ BuilderTy::FastMathFlagGuard Guard(*Builder);
+ Builder->SetFastMathFlags(I.getFastMathFlags());
+ Value *T = Builder->CreateFMul(Opnd1, Opnd1);
+
+ Value *R = Builder->CreateFMul(T, Y);
+ R->takeName(&I);
+ return ReplaceInstUsesWith(I, R);
+ }
+ }
+ }
+
+ if (!isa<Constant>(Op1))
+ std::swap(Opnd0, Opnd1);
+ else
+ break;
+ }
+
+ return Changed ? &I : nullptr;
}
/// SimplifyDivRemOfSelect - Try to fold a divide or remainder of a select
/// instruction.
bool InstCombiner::SimplifyDivRemOfSelect(BinaryOperator &I) {
SelectInst *SI = cast<SelectInst>(I.getOperand(1));
-
+
// div/rem X, (Cond ? 0 : Y) -> div/rem X, Y
int NonNullOperand = -1;
if (Constant *ST = dyn_cast<Constant>(SI->getOperand(1)))
if (Constant *ST = dyn_cast<Constant>(SI->getOperand(2)))
if (ST->isNullValue())
NonNullOperand = 1;
-
+
if (NonNullOperand == -1)
return false;
-
+
Value *SelectCond = SI->getOperand(0);
-
+
// 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.
if (SI->use_empty() && SelectCond->hasOneUse())
return true;
-
+
// Scan the current block backward, looking for other uses of SI.
BasicBlock::iterator BBI = &I, BBFront = I.getParent()->begin();
-
+
while (BBI != BBFront) {
--BBI;
// If we found a call to a function, we can't assume it will return, so
// information from below it cannot be propagated above it.
if (isa<CallInst>(BBI) && !isa<IntrinsicInst>(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) {
*I = SI->getOperand(NonNullOperand);
Worklist.Add(BBI);
} else if (*I == SelectCond) {
- *I = NonNullOperand == 1 ? ConstantInt::getTrue(BBI->getContext()) :
- ConstantInt::getFalse(BBI->getContext());
+ *I = Builder->getInt1(NonNullOperand == 1);
Worklist.Add(BBI);
}
}
-
+
// If we past the instruction, quit looking for it.
if (&*BBI == SI)
- SI = 0;
+ SI = nullptr;
if (&*BBI == SelectCond)
- SelectCond = 0;
-
+ SelectCond = nullptr;
+
// If we ran out of things to eliminate, break out of the loop.
- if (SelectCond == 0 && SI == 0)
+ if (!SelectCond && !SI)
break;
-
+
}
return true;
}
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// The RHS is known non-zero.
- if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this)) {
+ 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 (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
return &I;
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // (X / C1) / C2 -> X / (C1*C2)
- if (Instruction *LHS = dyn_cast<Instruction>(Op0))
- if (Instruction::BinaryOps(LHS->getOpcode()) == I.getOpcode())
- if (ConstantInt *LHSRHS = dyn_cast<ConstantInt>(LHS->getOperand(1))) {
- if (MultiplyOverflows(RHS, LHSRHS,
- I.getOpcode()==Instruction::SDiv))
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- return BinaryOperator::Create(I.getOpcode(), LHS->getOperand(0),
- ConstantExpr::getMul(RHS, LHSRHS));
+ if (Instruction *LHS = dyn_cast<Instruction>(Op0)) {
+ const APInt *C2;
+ if (match(Op1, m_APInt(C2))) {
+ Value *X;
+ const APInt *C1;
+ bool IsSigned = I.getOpcode() == Instruction::SDiv;
+
+ // (X / C1) / C2 -> X / (C1*C2)
+ if ((IsSigned && match(LHS, m_SDiv(m_Value(X), m_APInt(C1)))) ||
+ (!IsSigned && match(LHS, 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(I.getType(), Product));
+ }
+
+ if ((IsSigned && match(LHS, m_NSWMul(m_Value(X), m_APInt(C1)))) ||
+ (!IsSigned && match(LHS, 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)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ I.getOpcode(), X, ConstantInt::get(X->getType(), Quotient));
+ BO->setIsExact(I.isExact());
+ return BO;
}
- if (!RHS->isZero()) { // avoid X udiv 0
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
+ // (X * C1) / C2 -> X * (C1 / C2) if C1 is a multiple of C2.
+ if (IsMultiple(*C1, *C2, Quotient, IsSigned)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ Instruction::Mul, X, ConstantInt::get(X->getType(), Quotient));
+ BO->setHasNoUnsignedWrap(
+ !IsSigned &&
+ cast<OverflowingBinaryOperator>(LHS)->hasNoUnsignedWrap());
+ BO->setHasNoSignedWrap(
+ cast<OverflowingBinaryOperator>(LHS)->hasNoSignedWrap());
+ return BO;
+ }
+ }
+
+ if ((IsSigned && match(LHS, m_NSWShl(m_Value(X), m_APInt(C1))) &&
+ *C1 != C1->getBitWidth() - 1) ||
+ (!IsSigned && match(LHS, 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 C1.
+ if (IsMultiple(*C2, C1Shifted, Quotient, IsSigned)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ I.getOpcode(), X, ConstantInt::get(X->getType(), Quotient));
+ BO->setIsExact(I.isExact());
+ return BO;
+ }
+
+ // (X << C1) / C2 -> X * (C2 >> C1) if C1 is a multiple of C2.
+ if (IsMultiple(C1Shifted, *C2, Quotient, IsSigned)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ Instruction::Mul, X, ConstantInt::get(X->getType(), Quotient));
+ BO->setHasNoUnsignedWrap(
+ !IsSigned &&
+ cast<OverflowingBinaryOperator>(LHS)->hasNoUnsignedWrap());
+ BO->setHasNoSignedWrap(
+ cast<OverflowingBinaryOperator>(LHS)->hasNoSignedWrap());
+ return BO;
+ }
+ }
+
+ if (*C2 != 0) { // avoid X udiv 0
+ if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+ if (Instruction *R = FoldOpIntoSelect(I, SI))
+ return R;
+ if (isa<PHINode>(Op0))
+ if (Instruction *NV = FoldOpIntoPhi(I))
+ return NV;
+ }
+ }
+ }
+
+ if (ConstantInt *One = dyn_cast<ConstantInt>(Op0)) {
+ if (One->isOne() && !I.getType()->isIntegerTy(1)) {
+ bool isSigned = I.getOpcode() == Instruction::SDiv;
+ 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, One);
+ Value *Cmp = Builder->CreateICmpULT(
+ Inc, ConstantInt::get(I.getType(), 3));
+ return SelectInst::Create(Cmp, Op1, ConstantInt::get(I.getType(), 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, One), I.getType());
+ }
}
}
return &I;
// (X - (X rem Y)) / Y -> X / Y; usually originates as ((X / Y) * Y) / Y
- Value *X = 0, *Z = 0;
+ Value *X = nullptr, *Z = nullptr;
if (match(Op0, m_Sub(m_Value(X), m_Value(Z)))) { // (X - Z) / Y; Y = Op1
bool isSigned = I.getOpcode() == Instruction::SDiv;
if ((isSigned && match(Z, m_SRem(m_Specific(X), m_Specific(Op1)))) ||
return BinaryOperator::Create(I.getOpcode(), X, Op1);
}
- return 0;
+ return nullptr;
}
/// dyn_castZExtVal - Checks if V is a zext or constant that can
if (C->getValue().getActiveBits() <= cast<IntegerType>(Ty)->getBitWidth())
return ConstantExpr::getTrunc(C, Ty);
}
+ return nullptr;
+}
+
+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(nullptr) {}
+ UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand, size_t SLHS)
+ : FoldAction(FA), OperandToFold(InputOperand), SelectLHSIdx(SLHS) {}
+};
+} // namespace
+
+// 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;
+}
+
+// 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));
+
+ 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))
+ // X udiv C, where C >= signbit
+ if (C->getValue().isNegative()) {
+ 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, Depth))
+ if (visitUDivOperand(Op0, SI->getOperand(2), I, Actions, Depth)) {
+ Actions.push_back(UDivFoldAction(nullptr, 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))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifyUDivInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
// Handle the integer div common cases
if (Instruction *Common = commonIDivTransforms(I))
return Common;
-
- {
- // 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;
- }
- }
-
- 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));
- }
- }
// (x lshr C1) udiv C2 --> x udiv (C2 << C1)
- if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) {
+ {
Value *X;
- ConstantInt *C1;
- if (match(Op0, m_LShr(m_Value(X), m_ConstantInt(C1)))) {
- APInt NC = C2->getValue().shl(C1->getLimitedValue(C1->getBitWidth()-1));
- return BinaryOperator::CreateUDiv(X, Builder->getInt(NC));
- }
- }
-
- // 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);
+ const APInt *C1, *C2;
+ if (match(Op0, m_LShr(m_Value(X), m_APInt(C1))) &&
+ match(Op1, m_APInt(C2))) {
+ 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;
+ }
}
}
// (zext A) udiv (zext B) --> zext (A udiv B)
if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0))
if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy()))
- return new ZExtInst(Builder->CreateUDiv(ZOp0->getOperand(0), ZOp1, "div",
- I.isExact()),
- I.getType());
+ return new ZExtInst(
+ Builder->CreateUDiv(ZOp0->getOperand(0), ZOp1, "div", 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);
+ }
- return 0;
+ // 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) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifySDivInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifySDivInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
// Handle the integer div common cases
if (Instruction *Common = commonIDivTransforms(I))
return Common;
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // sdiv X, -1 == -X
- if (RHS->isAllOnesValue())
- return BinaryOperator::CreateNeg(Op0);
+ // sdiv X, -1 == -X
+ if (match(Op1, m_AllOnes()))
+ return BinaryOperator::CreateNeg(Op0);
+ if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
// sdiv X, C --> ashr exact X, log2(C)
if (I.isExact() && RHS->getValue().isNonNegative() &&
RHS->getValue().isPowerOf2()) {
RHS->getValue().exactLogBase2());
return BinaryOperator::CreateExactAShr(Op0, ShAmt, I.getName());
}
+ }
+
+ 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.
- if (SubOperator *Sub = dyn_cast<SubOperator>(Op0))
- if (match(Sub->getOperand(0), m_Zero()) && Sub->hasNoSignedWrap())
- return BinaryOperator::CreateSDiv(Sub->getOperand(1),
- ConstantExpr::getNeg(RHS));
+ 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.
if (I.getType()->isIntegerTy()) {
APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
- if (MaskedValueIsZero(Op0, Mask)) {
- if (MaskedValueIsZero(Op1, Mask)) {
- // X sdiv Y -> X udiv Y, if X and Y don't have sign bit set
- return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
+ 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 (match(Op1, m_Shl(m_Power2(), m_Value()))) {
+
+ if (isKnownToBeAPowerOfTwo(Op1, DL, /*OrZero*/ true, 0, AC, &I, DT)) {
// 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.
- return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
+ auto *BO = BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
+ BO->setIsExact(I.isExact());
+ return BO;
}
}
}
-
- return 0;
+
+ return nullptr;
+}
+
+/// CvtFDivConstToReciprocal tries to convert X/C into X*1/C if C not a special
+/// FP value and:
+/// 1) 1/C is exact, or
+/// 2) reciprocal is allowed.
+/// If the conversion was successful, the simplified expression "X * 1/C" is
+/// returned; otherwise, NULL is returned.
+///
+static Instruction *CvtFDivConstToReciprocal(Value *Dividend, Constant *Divisor,
+ bool AllowReciprocal) {
+ if (!isa<ConstantFP>(Divisor)) // TODO: handle vectors.
+ return nullptr;
+
+ const APFloat &FpVal = cast<ConstantFP>(Divisor)->getValueAPF();
+ APFloat Reciprocal(FpVal.getSemantics());
+ bool Cvt = FpVal.getExactInverse(&Reciprocal);
+
+ if (!Cvt && AllowReciprocal && FpVal.isFiniteNonZero()) {
+ Reciprocal = APFloat(FpVal.getSemantics(), 1.0f);
+ (void)Reciprocal.divide(FpVal, APFloat::rmNearestTiesToEven);
+ Cvt = !Reciprocal.isDenormal();
+ }
+
+ if (!Cvt)
+ return nullptr;
+
+ ConstantFP *R;
+ R = ConstantFP::get(Dividend->getType()->getContext(), Reciprocal);
+ return BinaryOperator::CreateFMul(Dividend, R);
}
Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifyFDivInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
return ReplaceInstUsesWith(I, V);
- if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
- const APFloat &Op1F = Op1C->getValueAPF();
+ if (Value *V = SimplifyFDivInst(Op0, Op1, I.getFastMathFlags(),
+ DL, TLI, DT, AC))
+ return ReplaceInstUsesWith(I, V);
+
+ if (isa<Constant>(Op0))
+ if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
+ if (Instruction *R = FoldOpIntoSelect(I, SI))
+ return R;
- // If the divisor has an exact multiplicative inverse we can turn the fdiv
- // into a cheaper fmul.
- APFloat Reciprocal(Op1F.getSemantics());
- if (Op1F.getExactInverse(&Reciprocal)) {
- ConstantFP *RFP = ConstantFP::get(Builder->getContext(), Reciprocal);
- return BinaryOperator::CreateFMul(Op0, RFP);
+ bool AllowReassociate = I.hasUnsafeAlgebra();
+ bool AllowReciprocal = I.hasAllowReciprocal();
+
+ if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
+ if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+ if (Instruction *R = FoldOpIntoSelect(I, SI))
+ return R;
+
+ if (AllowReassociate) {
+ Constant *C1 = nullptr;
+ Constant *C2 = Op1C;
+ Value *X;
+ Instruction *Res = nullptr;
+
+ if (match(Op0, m_FMul(m_Value(X), m_Constant(C1)))) {
+ // (X*C1)/C2 => X * (C1/C2)
+ //
+ Constant *C = ConstantExpr::getFDiv(C1, C2);
+ if (isNormalFp(C))
+ Res = BinaryOperator::CreateFMul(X, C);
+ } else if (match(Op0, m_FDiv(m_Value(X), m_Constant(C1)))) {
+ // (X/C1)/C2 => X /(C2*C1) [=> X * 1/(C2*C1) if reciprocal is allowed]
+ //
+ Constant *C = ConstantExpr::getFMul(C1, C2);
+ if (isNormalFp(C)) {
+ Res = CvtFDivConstToReciprocal(X, C, AllowReciprocal);
+ if (!Res)
+ Res = BinaryOperator::CreateFDiv(X, C);
+ }
+ }
+
+ if (Res) {
+ Res->setFastMathFlags(I.getFastMathFlags());
+ return Res;
+ }
+ }
+
+ // X / C => X * 1/C
+ if (Instruction *T = CvtFDivConstToReciprocal(Op0, Op1C, AllowReciprocal)) {
+ T->copyFastMathFlags(&I);
+ return T;
}
+
+ return nullptr;
}
- return 0;
+ if (AllowReassociate && isa<Constant>(Op0)) {
+ Constant *C1 = cast<Constant>(Op0), *C2;
+ Constant *Fold = nullptr;
+ Value *X;
+ bool CreateDiv = true;
+
+ // C1 / (X*C2) => (C1/C2) / X
+ if (match(Op1, m_FMul(m_Value(X), m_Constant(C2))))
+ Fold = ConstantExpr::getFDiv(C1, C2);
+ else if (match(Op1, m_FDiv(m_Value(X), m_Constant(C2)))) {
+ // C1 / (X/C2) => (C1*C2) / X
+ Fold = ConstantExpr::getFMul(C1, C2);
+ } else if (match(Op1, m_FDiv(m_Constant(C2), m_Value(X)))) {
+ // C1 / (C2/X) => (C1/C2) * X
+ Fold = ConstantExpr::getFDiv(C1, C2);
+ CreateDiv = false;
+ }
+
+ if (Fold && isNormalFp(Fold)) {
+ Instruction *R = CreateDiv ? BinaryOperator::CreateFDiv(Fold, X)
+ : BinaryOperator::CreateFMul(X, Fold);
+ R->setFastMathFlags(I.getFastMathFlags());
+ return R;
+ }
+ return nullptr;
+ }
+
+ if (AllowReassociate) {
+ Value *X, *Y;
+ Value *NewInst = nullptr;
+ Instruction *SimpR = nullptr;
+
+ if (Op0->hasOneUse() && match(Op0, m_FDiv(m_Value(X), m_Value(Y)))) {
+ // (X/Y) / Z => X / (Y*Z)
+ //
+ if (!isa<Constant>(Y) || !isa<Constant>(Op1)) {
+ NewInst = Builder->CreateFMul(Y, Op1);
+ if (Instruction *RI = dyn_cast<Instruction>(NewInst)) {
+ FastMathFlags Flags = I.getFastMathFlags();
+ Flags &= cast<Instruction>(Op0)->getFastMathFlags();
+ RI->setFastMathFlags(Flags);
+ }
+ SimpR = BinaryOperator::CreateFDiv(X, NewInst);
+ }
+ } else if (Op1->hasOneUse() && match(Op1, m_FDiv(m_Value(X), m_Value(Y)))) {
+ // Z / (X/Y) => Z*Y / X
+ //
+ if (!isa<Constant>(Y) || !isa<Constant>(Op0)) {
+ NewInst = Builder->CreateFMul(Op0, Y);
+ if (Instruction *RI = dyn_cast<Instruction>(NewInst)) {
+ FastMathFlags Flags = I.getFastMathFlags();
+ Flags &= cast<Instruction>(Op1)->getFastMathFlags();
+ RI->setFastMathFlags(Flags);
+ }
+ SimpR = BinaryOperator::CreateFDiv(NewInst, X);
+ }
+ }
+
+ if (NewInst) {
+ if (Instruction *T = dyn_cast<Instruction>(NewInst))
+ T->setDebugLoc(I.getDebugLoc());
+ SimpR->setFastMathFlags(I.getFastMathFlags());
+ return SimpR;
+ }
+ }
+
+ return nullptr;
}
/// This function implements the transforms common to both integer remainder
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// The RHS is known non-zero.
- if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this)) {
+ if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this, I)) {
I.setOperand(1, V);
return &I;
}
if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
return &I;
- if (isa<ConstantInt>(Op1)) {
+ 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 0;
+ return nullptr;
}
Instruction *InstCombiner::visitURem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifyURemInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifyURemInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
if (Instruction *common = commonIRemTransforms(I))
return common;
-
- // X urem C^2 -> X and C-1
- { const APInt *C;
- if (match(Op1, m_Power2(C)))
- return BinaryOperator::CreateAnd(Op0,
- ConstantInt::get(I.getType(), *C-1));
- }
- // Turn A % (C << N), where C is 2^k, into A & ((C << N)-1)
- if (match(Op1, m_Shl(m_Power2(), m_Value()))) {
+ // (zext A) urem (zext B) --> zext (A urem B)
+ if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0))
+ if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy()))
+ return new ZExtInst(Builder->CreateURem(ZOp0->getOperand(0), ZOp1),
+ I.getType());
+
+ // X urem Y -> X and Y-1, where Y is a power of 2,
+ if (isKnownToBeAPowerOfTwo(Op1, DL, /*OrZero*/ true, 0, AC, &I, DT)) {
Constant *N1 = Constant::getAllOnesValue(I.getType());
Value *Add = Builder->CreateAdd(Op1, N1);
return BinaryOperator::CreateAnd(Op0, Add);
}
- // urem X, (select Cond, 2^C1, 2^C2) -->
- // select Cond, (and X, C1-1), (and X, C2-1)
- // when 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)))) {
- Value *TrueAnd = Builder->CreateAnd(Op0, *C1-1, Op1->getName()+".t");
- Value *FalseAnd = Builder->CreateAnd(Op0, *C2-1, Op1->getName()+".f");
- return SelectInst::Create(Cond, TrueAnd, FalseAnd);
- }
+ // 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);
}
- // (zext A) urem (zext B) --> zext (A urem B)
- if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0))
- if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy()))
- return new ZExtInst(Builder->CreateURem(ZOp0->getOperand(0), ZOp1),
- I.getType());
-
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitSRem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifySRemInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifySRemInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
// Handle the integer rem common cases
if (Instruction *Common = commonIRemTransforms(I))
return Common;
-
- if (Value *RHSNeg = dyn_castNegVal(Op1))
- if (!isa<Constant>(RHSNeg) ||
- (isa<ConstantInt>(RHSNeg) &&
- cast<ConstantInt>(RHSNeg)->getValue().isStrictlyPositive())) {
- // X % -Y -> X % Y
+
+ {
+ const APInt *Y;
+ // X % -Y -> X % Y
+ if (match(Op1, m_APInt(Y)) && Y->isNegative() && !Y->isMinSignedValue()) {
Worklist.AddValue(I.getOperand(1));
- I.setOperand(1, RHSNeg);
+ 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.
if (I.getType()->isIntegerTy()) {
APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
- if (MaskedValueIsZero(Op1, Mask) && MaskedValueIsZero(Op0, Mask)) {
- // X srem Y -> X urem Y, if X and Y don't have sign bit set
+ 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());
}
}
bool hasMissing = false;
for (unsigned i = 0; i != VWidth; ++i) {
Constant *Elt = C->getAggregateElement(i);
- if (Elt == 0) {
+ if (!Elt) {
hasMissing = true;
break;
}
}
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitFRem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifyFRemInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifyFRemInst(Op0, Op1, I.getFastMathFlags(),
+ DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
// Handle cases involving: rem X, (select Cond, Y, Z)
if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
return &I;
- return 0;
+ return nullptr;
}
projects / oota-llvm.git / blobdiff