//===----------------------------------------------------------------------===//
#include "InstCombine.h"
-#include "llvm/IntrinsicInst.h"
#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/IR/IntrinsicInst.h"
#include "llvm/Support/PatternMatch.h"
using namespace llvm;
using namespace PatternMatch;
+
+/// 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) {
+ // 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;
+
+ 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.
+ isKnownToBeAPowerOfTwo(PowerOf2)) {
+ A = IC.Builder->CreateSub(A, B);
+ return IC.Builder->CreateShl(PowerOf2, 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() && isKnownToBeAPowerOfTwo(I->getOperand(0))) {
+ // 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)) {
+ 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;
+}
+
+
/// MultiplyOverflows - True if the multiply can not be expressed in an int
/// this size.
static bool MultiplyOverflows(ConstantInt *C1, ConstantInt *C2, bool sign) {
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);
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());
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, "tmp");
+ Value *Add = Builder->CreateMul(X, CI);
return BinaryOperator::CreateAdd(Add, Builder->CreateMul(C1, CI));
}
}
+
+ // (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;
+ if (Op0->hasOneUse()) {
+ ConstantInt *C1;
+ Value *Sub = 0;
+ 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));
+ }
+ }
+ }
}
-
+
// 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))
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);
if (match(Op1, m_Shl(m_One(), m_Value(Y))))
return BinaryOperator::CreateShl(Op0, Y);
}
-
+
// 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))
BoolCast = Op0, OtherOp = Op1;
if (BoolCast) {
Value *V = Builder->CreateSub(Constant::getNullValue(I.getType()),
- BoolCast, "tmp");
+ BoolCast);
return BinaryOperator::CreateAnd(V, OtherOp);
}
}
return Changed ? &I : 0;
}
+//
+// Detect pattern:
+//
+// log2(Y*0.5)
+//
+// And check for 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;
+
+ ConstantFP *CFP = dyn_cast<ConstantFP>(I->getOperand(0));
+ if (CFP && CFP->isExactlyValue(0.5)) {
+ Y = I->getOperand(1);
+ return;
+ }
+ CFP = dyn_cast<ConstantFP>(I->getOperand(1));
+ if (CFP && CFP->isExactlyValue(0.5))
+ Y = I->getOperand(0);
+}
+
+/// 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;
+
+ ConstantFP *C0 = dyn_cast<ConstantFP>(I->getOperand(0));
+ ConstantFP *C1 = dyn_cast<ConstantFP>(I->getOperand(1));
+
+ if (C0 && C1)
+ return false;
+
+ return (C0 && C0->getValueAPF().isNormal()) ||
+ (C1 && C1->getValueAPF().isNormal());
+}
+
+static bool isNormalFp(const ConstantFP *C) {
+ const APFloat &Flt = C->getValueAPF();
+ return Flt.isNormal() && !Flt.isDenormal();
+}
+
+/// 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, ConstantFP *C,
+ Instruction *InsertBefore) {
+ assert(isFMulOrFDivWithConstant(FMulOrDiv) && "V is invalid");
+
+ Value *Opnd0 = FMulOrDiv->getOperand(0);
+ Value *Opnd1 = FMulOrDiv->getOperand(1);
+
+ ConstantFP *C0 = dyn_cast<ConstantFP>(Opnd0);
+ ConstantFP *C1 = dyn_cast<ConstantFP>(Opnd1);
+
+ BinaryOperator *R = 0;
+
+ // (X * C0) * C => X * (C0*C)
+ if (FMulOrDiv->getOpcode() == Instruction::FMul) {
+ Constant *F = ConstantExpr::getFMul(C1 ? C1 : C0, C);
+ if (isNormalFp(cast<ConstantFP>(F)))
+ R = BinaryOperator::CreateFMul(C1 ? Opnd0 : Opnd1, F);
+ } else {
+ if (C0) {
+ // (C0 / X) * C => (C0 * C) / X
+ ConstantFP *F = cast<ConstantFP>(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
+ ConstantFP *F = cast<ConstantFP>(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(cast<ConstantFP>(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 (Op1C->getType()->isVectorTy()) {
- if (ConstantVector *Op1V = dyn_cast<ConstantVector>(Op1C)) {
- // As above, vector X*splat(1.0) -> X in all defined cases.
- if (Constant *Splat = Op1V->getSplatValue()) {
- if (ConstantFP *F = dyn_cast<ConstantFP>(Splat))
- if (F->isExactlyValue(1.0))
- return ReplaceInstUsesWith(I, Op0);
- }
- }
- }
+ if (isa<Constant>(Op0))
+ std::swap(Op0, Op1);
+
+ if (Value *V = SimplifyFMulInst(Op0, Op1, I.getFastMathFlags(), TD))
+ 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;
+
+ ConstantFP *C = dyn_cast<ConstantFP>(Op1);
+ if (C && AllowReassociate && C->getValueAPF().isNormal()) {
+ // 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)) {
+ Value *V = foldFMulConst(cast<Instruction>(Op0), C, &I);
+ if (V)
+ 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);
+ ConstantFP *C0 = dyn_cast<ConstantFP>(Opnd0);
+ ConstantFP *C1 = dyn_cast<ConstantFP>(Opnd1);
+ bool Swap = false;
+ if (C0) {
+ std::swap(C0, C1);
+ std::swap(Opnd0, Opnd1);
+ Swap = true;
+ }
+
+ if (C1 && C1->getValueAPF().isNormal() &&
+ isFMulOrFDivWithConstant(Opnd0)) {
+ Value *M1 = ConstantExpr::getFMul(C1, C);
+ Value *M0 = isNormalFp(cast<ConstantFP>(M1)) ?
+ foldFMulConst(cast<Instruction>(Opnd0), C, &I) :
+ 0;
+ if (M0 && M1) {
+ if (Swap && FAddSub->getOpcode() == Instruction::FSub)
+ std::swap(M0, M1);
+
+ Value *R = (FAddSub->getOpcode() == Instruction::FAdd) ?
+ BinaryOperator::CreateFAdd(M0, M1) :
+ BinaryOperator::CreateFSub(M0, M1);
+ Instruction *RI = cast<Instruction>(R);
+ RI->copyFastMathFlags(&I);
+ return RI;
+ }
+ }
+ }
+ }
+ }
+
+
+ // Under unsafe algebra do:
+ // X * log2(0.5*Y) = X*log2(Y) - X
+ if (I.hasUnsafeAlgebra()) {
+ Value *OpX = NULL;
+ Value *OpY = NULL;
+ 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) {
+ Log2->setArgOperand(0, OpY);
+ Value *FMulVal = Builder->CreateFMul(OpX, Log2);
+ Instruction *FMul = cast<Instruction>(FMulVal);
+ FMul->copyFastMathFlags(Log2);
+ Instruction *FSub = BinaryOperator::CreateFSub(FMulVal, OpX);
+ FSub->copyFastMathFlags(Log2);
+ return 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)) {
+ Value *N0 = dyn_castFNegVal(Opnd0, IgnoreZeroSign);
+ Value *N1 = dyn_castFNegVal(Opnd1, IgnoreZeroSign);
+
+ // -X * -Y => X*Y
+ if (N1)
+ return BinaryOperator::CreateFMul(N0, N1);
+
+ if (Opnd0->hasOneUse()) {
+ // -X * Y => -(X*Y) (Promote negation as high as possible)
+ Value *T = Builder->CreateFMul(N0, Opnd1);
+ cast<Instruction>(T)->setDebugLoc(I.getDebugLoc());
+ Instruction *Neg = BinaryOperator::CreateFNeg(T);
+ if (I.getFastMathFlags().any()) {
+ cast<Instruction>(T)->copyFastMathFlags(&I);
+ Neg->copyFastMathFlags(&I);
+ }
+ return 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 = 0;
+ if (Opnd0_0 == Opnd1 && Opnd0_1 != Opnd1)
+ Y = Opnd0_1;
+ else if (Opnd0_1 == Opnd1 && Opnd0_0 != Opnd1)
+ Y = Opnd0_0;
+
+ if (Y) {
+ Instruction *T = cast<Instruction>(Builder->CreateFMul(Opnd1, Opnd1));
+ T->copyFastMathFlags(&I);
+ T->setDebugLoc(I.getDebugLoc());
+
+ Instruction *R = BinaryOperator::CreateFMul(T, Y);
+ R->copyFastMathFlags(&I);
+ return R;
+ }
+ }
+ }
+
+ if (!isa<Constant>(Op1))
+ std::swap(Opnd0, Opnd1);
+ else
+ break;
+ }
return Changed ? &I : 0;
}
/// 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) {
Worklist.Add(BBI);
}
}
-
+
// If we past the instruction, quit looking for it.
if (&*BBI == SI)
SI = 0;
if (&*BBI == SelectCond)
SelectCond = 0;
-
+
// If we ran out of things to eliminate, break out of the loop.
if (SelectCond == 0 && SI == 0)
break;
-
+
}
return true;
}
Instruction *InstCombiner::commonIDivTransforms(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.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))
/// dyn_castZExtVal - Checks if V is a zext or constant that can
/// be truncated to Ty without losing bits.
-static Value *dyn_castZExtVal(Value *V, const Type *Ty) {
+static Value *dyn_castZExtVal(Value *V, Type *Ty) {
if (ZExtInst *Z = dyn_cast<ZExtInst>(V)) {
if (Z->getSrcTy() == Ty)
return Z->getOperand(0);
if (Instruction *Common = commonIDivTransforms(I))
return Common;
- if (ConstantInt *C = dyn_cast<ConstantInt>(Op1)) {
+ {
// X udiv 2^C -> X >> C
// Check to see if this is an unsigned division with an exact power of 2,
// if so, convert to a right shift.
- if (C->getValue().isPowerOf2()) { // 0 not included in isPowerOf2
+ const APInt *C;
+ if (match(Op1, m_Power2(C))) {
BinaryOperator *LShr =
- BinaryOperator::CreateLShr(Op0,
- ConstantInt::get(Op0->getType(), C->getValue().logBase2()));
+ 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);
}
}
+ // (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)))) {
+ 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(I.getType(), CI->logBase2()),
- "tmp");
+ 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;
// 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);
}
// X sdiv Y -> X udiv Y, iff X and Y don't have sign bit set
return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
}
-
+
if (match(Op1, m_Shl(m_Power2(), m_Value()))) {
// X sdiv (1 << Y) -> X udiv (1 << Y) ( -> X u>> Y)
// Safe because the only negative value (1 << Y) can take on is
}
}
}
-
+
return 0;
}
+/// 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 convertion was successful, the simplified expression "X * 1/C" is
+/// returned; otherwise, NULL is returned.
+///
+static Instruction *CvtFDivConstToReciprocal(Value *Dividend,
+ ConstantFP *Divisor,
+ bool AllowReciprocal) {
+ const APFloat &FpVal = Divisor->getValueAPF();
+ APFloat Reciprocal(FpVal.getSemantics());
+ bool Cvt = FpVal.getExactInverse(&Reciprocal);
+
+ if (!Cvt && AllowReciprocal && FpVal.isNormal()) {
+ Reciprocal = APFloat(FpVal.getSemantics(), 1.0f);
+ (void)Reciprocal.divide(FpVal, APFloat::rmNearestTiesToEven);
+ Cvt = !Reciprocal.isDenormal();
+ }
+
+ if (!Cvt)
+ return 0;
+
+ 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))
return ReplaceInstUsesWith(I, V);
+ bool AllowReassociate = I.hasUnsafeAlgebra();
+ bool AllowReciprocal = I.hasAllowReciprocal();
+
if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
- const APFloat &Op1F = Op1C->getValueAPF();
+ if (AllowReassociate) {
+ ConstantFP *C1 = 0;
+ ConstantFP *C2 = Op1C;
+ Value *X;
+ Instruction *Res = 0;
+
+ if (match(Op0, m_FMul(m_Value(X), m_ConstantFP(C1)))) {
+ // (X*C1)/C2 => X * (C1/C2)
+ //
+ Constant *C = ConstantExpr::getFDiv(C1, C2);
+ const APFloat &F = cast<ConstantFP>(C)->getValueAPF();
+ if (F.isNormal() && !F.isDenormal())
+ Res = BinaryOperator::CreateFMul(X, C);
+ } else if (match(Op0, m_FDiv(m_Value(X), m_ConstantFP(C1)))) {
+ // (X/C1)/C2 => X /(C2*C1) [=> X * 1/(C2*C1) if reciprocal is allowed]
+ //
+ Constant *C = ConstantExpr::getFMul(C1, C2);
+ const APFloat &F = cast<ConstantFP>(C)->getValueAPF();
+ if (F.isNormal() && !F.isDenormal()) {
+ Res = CvtFDivConstToReciprocal(X, cast<ConstantFP>(C),
+ AllowReciprocal);
+ if (!Res)
+ Res = BinaryOperator::CreateFDiv(X, C);
+ }
+ }
- // 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);
+ if (Res) {
+ Res->setFastMathFlags(I.getFastMathFlags());
+ return Res;
+ }
}
- }
- return 0;
-}
+ // X / C => X * 1/C
+ if (Instruction *T = CvtFDivConstToReciprocal(Op0, Op1C, AllowReciprocal))
+ return T;
-/// This function implements the transforms on rem instructions that work
-/// regardless of the kind of rem instruction it is (urem, srem, or frem). It
-/// is used by the visitors to those instructions.
-/// @brief Transforms common to all three rem instructions
-Instruction *InstCombiner::commonRemTransforms(BinaryOperator &I) {
- Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ return 0;
+ }
- if (isa<UndefValue>(Op0)) { // undef % X -> 0
- if (I.getType()->isFPOrFPVectorTy())
- return ReplaceInstUsesWith(I, Op0); // X % undef -> undef (could be SNaN)
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
+ if (AllowReassociate && isa<ConstantFP>(Op0)) {
+ ConstantFP *C1 = cast<ConstantFP>(Op0), *C2;
+ Constant *Fold = 0;
+ Value *X;
+ bool CreateDiv = true;
+
+ // C1 / (X*C2) => (C1/C2) / X
+ if (match(Op1, m_FMul(m_Value(X), m_ConstantFP(C2))))
+ Fold = ConstantExpr::getFDiv(C1, C2);
+ else if (match(Op1, m_FDiv(m_Value(X), m_ConstantFP(C2)))) {
+ // C1 / (X/C2) => (C1*C2) / X
+ Fold = ConstantExpr::getFMul(C1, C2);
+ } else if (match(Op1, m_FDiv(m_ConstantFP(C2), m_Value(X)))) {
+ // C1 / (C2/X) => (C1/C2) * X
+ Fold = ConstantExpr::getFDiv(C1, C2);
+ CreateDiv = false;
+ }
+
+ if (Fold) {
+ const APFloat &FoldC = cast<ConstantFP>(Fold)->getValueAPF();
+ if (FoldC.isNormal() && !FoldC.isDenormal()) {
+ Instruction *R = CreateDiv ?
+ BinaryOperator::CreateFDiv(Fold, X) :
+ BinaryOperator::CreateFMul(X, Fold);
+ R->setFastMathFlags(I.getFastMathFlags());
+ return R;
+ }
+ }
+ return 0;
}
- if (isa<UndefValue>(Op1))
- return ReplaceInstUsesWith(I, Op1); // X % undef -> undef
- // Handle cases involving: rem X, (select Cond, Y, Z)
- if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
- return &I;
+ if (AllowReassociate) {
+ Value *X, *Y;
+ Value *NewInst = 0;
+ Instruction *SimpR = 0;
+
+ if (Op0->hasOneUse() && match(Op0, m_FDiv(m_Value(X), m_Value(Y)))) {
+ // (X/Y) / Z => X / (Y*Z)
+ //
+ if (!isa<ConstantFP>(Y) || !isa<ConstantFP>(Op1)) {
+ NewInst = Builder->CreateFMul(Y, Op1);
+ 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<ConstantFP>(Y) || !isa<ConstantFP>(Op0)) {
+ NewInst = Builder->CreateFMul(Op0, Y);
+ 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 0;
}
Instruction *InstCombiner::commonIRemTransforms(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Instruction *common = commonRemTransforms(I))
- return common;
-
- // X % X == 0
- if (Op0 == Op1)
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
- // 0 % X == 0 for integer, we don't need to preserve faults!
- if (Constant *LHS = dyn_cast<Constant>(Op0))
- if (LHS->isNullValue())
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
+ // The RHS is known non-zero.
+ if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this)) {
+ I.setOperand(1, V);
+ return &I;
+ }
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // X % 0 == undef, we don't need to preserve faults!
- if (RHS->equalsInt(0))
- return ReplaceInstUsesWith(I, UndefValue::get(I.getType()));
-
- if (RHS->equalsInt(1)) // X % 1 == 0
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
+ // Handle cases involving: rem X, (select Cond, Y, Z)
+ if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
+ return &I;
+ if (isa<ConstantInt>(Op1)) {
if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) {
if (SelectInst *SI = dyn_cast<SelectInst>(Op0I)) {
if (Instruction *R = FoldOpIntoSelect(I, SI))
Instruction *InstCombiner::visitURem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyURemInst(Op0, Op1, TD))
+ 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)))
ConstantInt::get(I.getType(), *C-1));
}
- // Turn A % (C << N), where C is 2^k, into A & ((C << N)-1)
+ // Turn A % (C << N), where C is 2^k, into A & ((C << N)-1)
if (match(Op1, m_Shl(m_Power2(), m_Value()))) {
Constant *N1 = Constant::getAllOnesValue(I.getType());
- Value *Add = Builder->CreateAdd(Op1, N1, "tmp");
+ Value *Add = Builder->CreateAdd(Op1, N1);
return BinaryOperator::CreateAnd(Op0, Add);
}
Instruction *InstCombiner::visitSRem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifySRemInst(Op0, Op1, TD))
+ 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) &&
}
// If it's a constant vector, flip any negative values positive.
- if (ConstantVector *RHSV = dyn_cast<ConstantVector>(Op1)) {
- unsigned VWidth = RHSV->getNumOperands();
+ if (isa<ConstantVector>(Op1) || isa<ConstantDataVector>(Op1)) {
+ Constant *C = cast<Constant>(Op1);
+ unsigned VWidth = C->getType()->getVectorNumElements();
bool hasNegative = false;
- for (unsigned i = 0; !hasNegative && i != VWidth; ++i)
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(RHSV->getOperand(i)))
- if (RHS->getValue().isNegative())
+ bool hasMissing = false;
+ for (unsigned i = 0; i != VWidth; ++i) {
+ Constant *Elt = C->getAggregateElement(i);
+ if (Elt == 0) {
+ hasMissing = true;
+ break;
+ }
+
+ if (ConstantInt *RHS = dyn_cast<ConstantInt>(Elt))
+ if (RHS->isNegative())
hasNegative = true;
+ }
- if (hasNegative) {
- std::vector<Constant *> Elts(VWidth);
+ if (hasNegative && !hasMissing) {
+ SmallVector<Constant *, 16> Elts(VWidth);
for (unsigned i = 0; i != VWidth; ++i) {
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(RHSV->getOperand(i))) {
- if (RHS->getValue().isNegative())
+ 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));
- else
- Elts[i] = RHS;
}
}
Constant *NewRHSV = ConstantVector::get(Elts);
- if (NewRHSV != RHSV) {
+ if (NewRHSV != C) { // Don't loop on -MININT
Worklist.AddValue(I.getOperand(1));
I.setOperand(1, NewRHSV);
return &I;
}
Instruction *InstCombiner::visitFRem(BinaryOperator &I) {
- return commonRemTransforms(I);
-}
+ Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+
+ if (Value *V = SimplifyFRemInst(Op0, Op1, TD))
+ return ReplaceInstUsesWith(I, V);
+
+ // Handle cases involving: rem X, (select Cond, Y, Z)
+ if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
+ return &I;
+ return 0;
+}
projects / oota-llvm.git / blobdiff