using namespace llvm;
using namespace PatternMatch;
+#define DEBUG_TYPE "instcombine"
+
static ConstantInt *getOne(Constant *C) {
return ConstantInt::get(cast<IntegerType>(C->getType()), 1);
}
FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP, GlobalVariable *GV,
CmpInst &ICI, ConstantInt *AndCst) {
// We need TD information to know the pointer size unless this is inbounds.
- if (!GEP->isInBounds() && DL == 0)
- return 0;
+ if (!GEP->isInBounds() && !DL)
+ return nullptr;
Constant *Init = GV->getInitializer();
if (!isa<ConstantArray>(Init) && !isa<ConstantDataArray>(Init))
- return 0;
+ return nullptr;
uint64_t ArrayElementCount = Init->getType()->getArrayNumElements();
- if (ArrayElementCount > 1024) return 0; // Don't blow up on huge arrays.
+ if (ArrayElementCount > 1024) return nullptr; // Don't blow up on huge arrays.
// There are many forms of this optimization we can handle, for now, just do
// the simple index into a single-dimensional array.
!isa<ConstantInt>(GEP->getOperand(1)) ||
!cast<ConstantInt>(GEP->getOperand(1))->isZero() ||
isa<Constant>(GEP->getOperand(2)))
- return 0;
+ return nullptr;
// Check that indices after the variable are constants and in-range for the
// type they index. Collect the indices. This is typically for arrays of
Type *EltTy = Init->getType()->getArrayElementType();
for (unsigned i = 3, e = GEP->getNumOperands(); i != e; ++i) {
ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(i));
- if (Idx == 0) return 0; // Variable index.
+ if (!Idx) return nullptr; // Variable index.
uint64_t IdxVal = Idx->getZExtValue();
- if ((unsigned)IdxVal != IdxVal) return 0; // Too large array index.
+ if ((unsigned)IdxVal != IdxVal) return nullptr; // Too large array index.
if (StructType *STy = dyn_cast<StructType>(EltTy))
EltTy = STy->getElementType(IdxVal);
else if (ArrayType *ATy = dyn_cast<ArrayType>(EltTy)) {
- if (IdxVal >= ATy->getNumElements()) return 0;
+ if (IdxVal >= ATy->getNumElements()) return nullptr;
EltTy = ATy->getElementType();
} else {
- return 0; // Unknown type.
+ return nullptr; // Unknown type.
}
LaterIndices.push_back(IdxVal);
Constant *CompareRHS = cast<Constant>(ICI.getOperand(1));
for (unsigned i = 0, e = ArrayElementCount; i != e; ++i) {
Constant *Elt = Init->getAggregateElement(i);
- if (Elt == 0) return 0;
+ if (!Elt) return nullptr;
// If this is indexing an array of structures, get the structure element.
if (!LaterIndices.empty())
// If we can't compute the result for any of the elements, we have to give
// up evaluating the entire conditional.
- if (!isa<ConstantInt>(C)) return 0;
+ if (!isa<ConstantInt>(C)) return nullptr;
// Otherwise, we know if the comparison is true or false for this element,
// update our state machines.
if ((i & 8) == 0 && i >= 64 && SecondTrueElement == Overdefined &&
SecondFalseElement == Overdefined && TrueRangeEnd == Overdefined &&
FalseRangeEnd == Overdefined)
- return 0;
+ return nullptr;
}
// Now that we've scanned the entire array, emit our new comparison(s). We
// of this load, replace it with computation that does:
// ((magic_cst >> i) & 1) != 0
{
- Type *Ty = 0;
+ Type *Ty = nullptr;
// Look for an appropriate type:
// - The type of Idx if the magic fits
else if (ArrayElementCount <= 32)
Ty = Type::getInt32Ty(Init->getContext());
- if (Ty != 0) {
+ if (Ty) {
Value *V = Builder->CreateIntCast(Idx, Ty, false);
V = Builder->CreateLShr(ConstantInt::get(Ty, MagicBitvector), V);
V = Builder->CreateAnd(ConstantInt::get(Ty, 1), V);
}
}
- return 0;
+ return nullptr;
}
// If there are no variable indices, we must have a constant offset, just
// evaluate it the general way.
- if (i == e) return 0;
+ if (i == e) return nullptr;
Value *VariableIdx = GEP->getOperand(i);
// Determine the scale factor of the variable element. For example, this is
// Verify that there are no other variable indices. If so, emit the hard way.
for (++i, ++GTI; i != e; ++i, ++GTI) {
ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i));
- if (!CI) return 0;
+ if (!CI) return nullptr;
// Compute the aggregate offset of constant indices.
if (CI->isZero()) continue;
// multiple of the variable scale.
int64_t NewOffs = Offset / (int64_t)VariableScale;
if (Offset != NewOffs*(int64_t)VariableScale)
- return 0;
+ return nullptr;
// Okay, we can do this evaluation. Start by converting the index to intptr.
if (VariableIdx->getType() != IntPtrTy)
// e.g. "&foo[0] <s &foo[1]" can't be folded to "true" because "foo" could be
// the maximum signed value for the pointer type.
if (ICmpInst::isSigned(Cond))
- return 0;
+ return nullptr;
- // Look through bitcasts.
- if (BitCastInst *BCI = dyn_cast<BitCastInst>(RHS))
- RHS = BCI->getOperand(0);
+ // Look through bitcasts and addrspacecasts. We do not however want to remove
+ // 0 GEPs.
+ if (!isa<GetElementPtrInst>(RHS))
+ RHS = RHS->stripPointerCasts();
Value *PtrBase = GEPLHS->getOperand(0);
if (DL && PtrBase == RHS && GEPLHS->isInBounds()) {
Value *Offset = EvaluateGEPOffsetExpression(GEPLHS, *this);
// If not, synthesize the offset the hard way.
- if (Offset == 0)
+ if (!Offset)
Offset = EmitGEPOffset(GEPLHS);
return new ICmpInst(ICmpInst::getSignedPredicate(Cond), Offset,
Constant::getNullValue(Offset->getType()));
(GEPRHS->hasAllConstantIndices() || GEPRHS->hasOneUse()) &&
PtrBase->stripPointerCasts() ==
GEPRHS->getOperand(0)->stripPointerCasts()) {
+ Value *LOffset = EmitGEPOffset(GEPLHS);
+ Value *ROffset = EmitGEPOffset(GEPRHS);
+
+ // If we looked through an addrspacecast between different sized address
+ // spaces, the LHS and RHS pointers are different sized
+ // integers. Truncate to the smaller one.
+ Type *LHSIndexTy = LOffset->getType();
+ Type *RHSIndexTy = ROffset->getType();
+ if (LHSIndexTy != RHSIndexTy) {
+ if (LHSIndexTy->getPrimitiveSizeInBits() <
+ RHSIndexTy->getPrimitiveSizeInBits()) {
+ ROffset = Builder->CreateTrunc(ROffset, LHSIndexTy);
+ } else
+ LOffset = Builder->CreateTrunc(LOffset, RHSIndexTy);
+ }
+
Value *Cmp = Builder->CreateICmp(ICmpInst::getSignedPredicate(Cond),
- EmitGEPOffset(GEPLHS),
- EmitGEPOffset(GEPRHS));
+ LOffset, ROffset);
return ReplaceInstUsesWith(I, Cmp);
}
// Otherwise, the base pointers are different and the indices are
// different, bail out.
- return 0;
+ return nullptr;
}
// If one of the GEPs has all zero indices, recurse.
- bool AllZeros = true;
- for (unsigned i = 1, e = GEPLHS->getNumOperands(); i != e; ++i)
- if (!isa<Constant>(GEPLHS->getOperand(i)) ||
- !cast<Constant>(GEPLHS->getOperand(i))->isNullValue()) {
- AllZeros = false;
- break;
- }
- if (AllZeros)
+ if (GEPLHS->hasAllZeroIndices())
return FoldGEPICmp(GEPRHS, GEPLHS->getOperand(0),
ICmpInst::getSwappedPredicate(Cond), I);
// If the other GEP has all zero indices, recurse.
- AllZeros = true;
- for (unsigned i = 1, e = GEPRHS->getNumOperands(); i != e; ++i)
- if (!isa<Constant>(GEPRHS->getOperand(i)) ||
- !cast<Constant>(GEPRHS->getOperand(i))->isNullValue()) {
- AllZeros = false;
- break;
- }
- if (AllZeros)
+ if (GEPRHS->hasAllZeroIndices())
return FoldGEPICmp(GEPLHS, GEPRHS->getOperand(0), Cond, I);
bool GEPsInBounds = GEPLHS->isInBounds() && GEPRHS->isInBounds();
return new ICmpInst(ICmpInst::getSignedPredicate(Cond), L, R);
}
}
- return 0;
+ return nullptr;
}
/// FoldICmpAddOpCst - Fold "icmp pred (X+CI), X".
Instruction *InstCombiner::FoldICmpAddOpCst(Instruction &ICI,
Value *X, ConstantInt *CI,
ICmpInst::Predicate Pred) {
- // If we have X+0, exit early (simplifying logic below) and let it get folded
- // elsewhere. icmp X+0, X -> icmp X, X
- if (CI->isZero()) {
- bool isTrue = ICmpInst::isTrueWhenEqual(Pred);
- return ReplaceInstUsesWith(ICI, ConstantInt::get(ICI.getType(), isTrue));
- }
-
- // (X+4) == X -> false.
- if (Pred == ICmpInst::ICMP_EQ)
- return ReplaceInstUsesWith(ICI, Builder->getFalse());
-
- // (X+4) != X -> true.
- if (Pred == ICmpInst::ICMP_NE)
- return ReplaceInstUsesWith(ICI, Builder->getTrue());
-
// From this point on, we know that (X+C <= X) --> (X+C < X) because C != 0,
// so the values can never be equal. Similarly for all other "or equals"
// operators.
// if it finds it.
bool DivIsSigned = DivI->getOpcode() == Instruction::SDiv;
if (!ICI.isEquality() && DivIsSigned != ICI.isSigned())
- return 0;
+ return nullptr;
if (DivRHS->isZero())
- return 0; // The ProdOV computation fails on divide by zero.
+ return nullptr; // The ProdOV computation fails on divide by zero.
if (DivIsSigned && DivRHS->isAllOnesValue())
- return 0; // The overflow computation also screws up here
+ return nullptr; // The overflow computation also screws up here
if (DivRHS->isOne()) {
// This eliminates some funny cases with INT_MIN.
ICI.setOperand(0, DivI->getOperand(0)); // X/1 == X.
// overflow variable is set to 0 if it's corresponding bound variable is valid
// -1 if overflowed off the bottom end, or +1 if overflowed off the top end.
int LoOverflow = 0, HiOverflow = 0;
- Constant *LoBound = 0, *HiBound = 0;
+ Constant *LoBound = nullptr, *HiBound = nullptr;
if (!DivIsSigned) { // udiv
// e.g. X/5 op 3 --> [15, 20)
HiBound = cast<ConstantInt>(ConstantExpr::getNeg(RangeSize));
if (HiBound == DivRHS) { // -INTMIN = INTMIN
HiOverflow = 1; // [INTMIN+1, overflow)
- HiBound = 0; // e.g. X/INTMIN = 0 --> X > INTMIN
+ HiBound = nullptr; // e.g. X/INTMIN = 0 --> X > INTMIN
}
} else if (CmpRHSV.isStrictlyPositive()) { // (X / neg) op pos
// e.g. X/-5 op 3 --> [-19, -14)
uint32_t TypeBits = CmpRHSV.getBitWidth();
uint32_t ShAmtVal = (uint32_t)ShAmt->getLimitedValue(TypeBits);
if (ShAmtVal >= TypeBits || ShAmtVal == 0)
- return 0;
+ return nullptr;
if (!ICI.isEquality()) {
// If we have an unsigned comparison and an ashr, we can't simplify this.
// Similarly for signed comparisons with lshr.
if (ICI.isSigned() != (Shr->getOpcode() == Instruction::AShr))
- return 0;
+ return nullptr;
// Otherwise, all lshr and most exact ashr's are equivalent to a udiv/sdiv
// by a power of 2. Since we already have logic to simplify these,
// transform to div and then simplify the resultant comparison.
if (Shr->getOpcode() == Instruction::AShr &&
(!Shr->isExact() || ShAmtVal == TypeBits - 1))
- return 0;
+ return nullptr;
// Revisit the shift (to delete it).
Worklist.Add(Shr);
// If the builder folded the binop, just return it.
BinaryOperator *TheDiv = dyn_cast<BinaryOperator>(Tmp);
- if (TheDiv == 0)
+ if (!TheDiv)
return &ICI;
// Otherwise, fold this div/compare.
Mask, Shr->getName()+".mask");
return new ICmpInst(ICI.getPredicate(), And, ShiftedCmpRHS);
}
- return 0;
+ return nullptr;
+}
+
+/// FoldICmpCstShrCst - Handle "(icmp eq/ne (ashr/lshr const2, A), const1)" ->
+/// (icmp eq/ne A, Log2(const2/const1)) ->
+/// (icmp eq/ne A, Log2(const2) - Log2(const1)).
+Instruction *InstCombiner::FoldICmpCstShrCst(ICmpInst &I, Value *Op, Value *A,
+ ConstantInt *CI1,
+ ConstantInt *CI2) {
+ assert(I.isEquality() && "Cannot fold icmp gt/lt");
+
+ auto getConstant = [&I, this](bool IsTrue) {
+ if (I.getPredicate() == I.ICMP_NE)
+ IsTrue = !IsTrue;
+ return ReplaceInstUsesWith(I, ConstantInt::get(I.getType(), IsTrue));
+ };
+
+ auto getICmp = [&I](CmpInst::Predicate Pred, Value *LHS, Value *RHS) {
+ if (I.getPredicate() == I.ICMP_NE)
+ Pred = CmpInst::getInversePredicate(Pred);
+ return new ICmpInst(Pred, LHS, RHS);
+ };
+
+ APInt AP1 = CI1->getValue();
+ APInt AP2 = CI2->getValue();
+
+ // Don't bother doing any work for cases which InstSimplify handles.
+ if (AP2 == 0)
+ return nullptr;
+ bool IsAShr = isa<AShrOperator>(Op);
+ if (IsAShr) {
+ if (AP2.isAllOnesValue())
+ return nullptr;
+ if (AP2.isNegative() != AP1.isNegative())
+ return nullptr;
+ if (AP2.sgt(AP1))
+ return nullptr;
+ }
+
+ if (!AP1)
+ // 'A' must be large enough to shift out the highest set bit.
+ return getICmp(I.ICMP_UGT, A,
+ ConstantInt::get(A->getType(), AP2.logBase2()));
+
+ if (AP1 == AP2)
+ return getICmp(I.ICMP_EQ, A, ConstantInt::getNullValue(A->getType()));
+
+ // Get the distance between the highest bit that's set.
+ int Shift;
+ // Both the constants are negative, take their positive to calculate log.
+ if (IsAShr && AP1.isNegative())
+ // Get the ones' complement of AP2 and AP1 when computing the distance.
+ Shift = (~AP2).logBase2() - (~AP1).logBase2();
+ else
+ Shift = AP2.logBase2() - AP1.logBase2();
+
+ if (Shift > 0) {
+ if (IsAShr ? AP1 == AP2.ashr(Shift) : AP1 == AP2.lshr(Shift))
+ return getICmp(I.ICMP_EQ, A, ConstantInt::get(A->getType(), Shift));
+ }
+ // Shifting const2 will never be equal to const1.
+ return getConstant(false);
}
+/// FoldICmpCstShlCst - Handle "(icmp eq/ne (shl const2, A), const1)" ->
+/// (icmp eq/ne A, TrailingZeros(const1) - TrailingZeros(const2)).
+Instruction *InstCombiner::FoldICmpCstShlCst(ICmpInst &I, Value *Op, Value *A,
+ ConstantInt *CI1,
+ ConstantInt *CI2) {
+ assert(I.isEquality() && "Cannot fold icmp gt/lt");
+
+ auto getConstant = [&I, this](bool IsTrue) {
+ if (I.getPredicate() == I.ICMP_NE)
+ IsTrue = !IsTrue;
+ return ReplaceInstUsesWith(I, ConstantInt::get(I.getType(), IsTrue));
+ };
+
+ auto getICmp = [&I](CmpInst::Predicate Pred, Value *LHS, Value *RHS) {
+ if (I.getPredicate() == I.ICMP_NE)
+ Pred = CmpInst::getInversePredicate(Pred);
+ return new ICmpInst(Pred, LHS, RHS);
+ };
+
+ APInt AP1 = CI1->getValue();
+ APInt AP2 = CI2->getValue();
+
+ // Don't bother doing any work for cases which InstSimplify handles.
+ if (AP2 == 0)
+ return nullptr;
+
+ unsigned AP2TrailingZeros = AP2.countTrailingZeros();
+
+ if (!AP1 && AP2TrailingZeros != 0)
+ return getICmp(I.ICMP_UGE, A,
+ ConstantInt::get(A->getType(), AP2.getBitWidth() - AP2TrailingZeros));
+
+ if (AP1 == AP2)
+ return getICmp(I.ICMP_EQ, A, ConstantInt::getNullValue(A->getType()));
+
+ // Get the distance between the lowest bits that are set.
+ int Shift = AP1.countTrailingZeros() - AP2TrailingZeros;
+
+ if (Shift > 0 && AP2.shl(Shift) == AP1)
+ return getICmp(I.ICMP_EQ, A, ConstantInt::get(A->getType(), Shift));
+
+ // Shifting const2 will never be equal to const1.
+ return getConstant(false);
+}
/// visitICmpInstWithInstAndIntCst - Handle "icmp (instr, intcst)".
///
unsigned DstBits = LHSI->getType()->getPrimitiveSizeInBits(),
SrcBits = LHSI->getOperand(0)->getType()->getPrimitiveSizeInBits();
APInt KnownZero(SrcBits, 0), KnownOne(SrcBits, 0);
- ComputeMaskedBits(LHSI->getOperand(0), KnownZero, KnownOne);
+ computeKnownBits(LHSI->getOperand(0), KnownZero, KnownOne, 0, &ICI);
// If all the high bits are known, we can do this xform.
if ((KnownZero|KnownOne).countLeadingOnes() >= SrcBits-DstBits) {
// access.
BinaryOperator *Shift = dyn_cast<BinaryOperator>(LHSI->getOperand(0));
if (Shift && !Shift->isShift())
- Shift = 0;
+ Shift = nullptr;
ConstantInt *ShAmt;
- ShAmt = Shift ? dyn_cast<ConstantInt>(Shift->getOperand(1)) : 0;
+ ShAmt = Shift ? dyn_cast<ConstantInt>(Shift->getOperand(1)) : nullptr;
// This seemingly simple opportunity to fold away a shift turns out to
// be rather complicated. See PR17827
return &ICI;
}
+ // (icmp pred (and (or (lshr X, Y), X), 1), 0) -->
+ // (icmp pred (and X, (or (shl 1, Y), 1), 0))
+ //
+ // iff pred isn't signed
+ {
+ Value *X, *Y, *LShr;
+ if (!ICI.isSigned() && RHSV == 0) {
+ if (match(LHSI->getOperand(1), m_One())) {
+ Constant *One = cast<Constant>(LHSI->getOperand(1));
+ Value *Or = LHSI->getOperand(0);
+ if (match(Or, m_Or(m_Value(LShr), m_Value(X))) &&
+ match(LShr, m_LShr(m_Specific(X), m_Value(Y)))) {
+ unsigned UsesRemoved = 0;
+ if (LHSI->hasOneUse())
+ ++UsesRemoved;
+ if (Or->hasOneUse())
+ ++UsesRemoved;
+ if (LShr->hasOneUse())
+ ++UsesRemoved;
+ Value *NewOr = nullptr;
+ // Compute X & ((1 << Y) | 1)
+ if (auto *C = dyn_cast<Constant>(Y)) {
+ if (UsesRemoved >= 1)
+ NewOr =
+ ConstantExpr::getOr(ConstantExpr::getNUWShl(One, C), One);
+ } else {
+ if (UsesRemoved >= 3)
+ NewOr = Builder->CreateOr(Builder->CreateShl(One, Y,
+ LShr->getName(),
+ /*HasNUW=*/true),
+ One, Or->getName());
+ }
+ if (NewOr) {
+ Value *NewAnd = Builder->CreateAnd(X, NewOr, LHSI->getName());
+ ICI.setOperand(0, NewAnd);
+ return &ICI;
+ }
+ }
+ }
+ }
+ }
+
// Replace ((X & AndCst) > RHSV) with ((X & AndCst) != 0), if any
// bit set in (X & AndCst) will produce a result greater than RHSV.
if (ICI.getPredicate() == ICmpInst::ICMP_UGT) {
unsigned RHSLog2 = RHSV.logBase2();
// (1 << X) >= 2147483648 -> X >= 31 -> X == 31
- // (1 << X) > 2147483648 -> X > 31 -> false
- // (1 << X) <= 2147483648 -> X <= 31 -> true
// (1 << X) < 2147483648 -> X < 31 -> X != 31
if (RHSLog2 == TypeBits-1) {
if (Pred == ICmpInst::ICMP_UGE)
Pred = ICmpInst::ICMP_EQ;
- else if (Pred == ICmpInst::ICMP_UGT)
- return ReplaceInstUsesWith(ICI, Builder->getFalse());
- else if (Pred == ICmpInst::ICMP_ULE)
- return ReplaceInstUsesWith(ICI, Builder->getTrue());
else if (Pred == ICmpInst::ICMP_ULT)
Pred = ICmpInst::ICMP_NE;
}
if (RHSVIsPowerOf2)
return new ICmpInst(
Pred, X, ConstantInt::get(RHS->getType(), RHSV.logBase2()));
-
- return ReplaceInstUsesWith(
- ICI, Pred == ICmpInst::ICMP_EQ ? Builder->getFalse()
- : Builder->getTrue());
}
}
break;
}
}
}
- return 0;
+ return nullptr;
}
/// visitICmpInstWithCastAndCast - Handle icmp (cast x to y), (cast/cst).
// integer type is the same size as the pointer type.
if (DL && LHSCI->getOpcode() == Instruction::PtrToInt &&
DL->getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth()) {
- Value *RHSOp = 0;
+ Value *RHSOp = nullptr;
if (Constant *RHSC = dyn_cast<Constant>(ICI.getOperand(1))) {
RHSOp = ConstantExpr::getIntToPtr(RHSC, SrcTy);
} else if (PtrToIntInst *RHSC = dyn_cast<PtrToIntInst>(ICI.getOperand(1))) {
// Enforce this.
if (LHSCI->getOpcode() != Instruction::ZExt &&
LHSCI->getOpcode() != Instruction::SExt)
- return 0;
+ return nullptr;
bool isSignedExt = LHSCI->getOpcode() == Instruction::SExt;
bool isSignedCmp = ICI.isSigned();
// Not an extension from the same type?
RHSCIOp = CI->getOperand(0);
if (RHSCIOp->getType() != LHSCIOp->getType())
- return 0;
+ return nullptr;
// If the signedness of the two casts doesn't agree (i.e. one is a sext
// and the other is a zext), then we can't handle this.
if (CI->getOpcode() != LHSCI->getOpcode())
- return 0;
+ return nullptr;
// Deal with equality cases early.
if (ICI.isEquality())
// If we aren't dealing with a constant on the RHS, exit early
ConstantInt *CI = dyn_cast<ConstantInt>(ICI.getOperand(1));
if (!CI)
- return 0;
+ return nullptr;
// Compute the constant that would happen if we truncated to SrcTy then
// reextended to DestTy.
// by SimplifyICmpInst, so only deal with the tricky case.
if (isSignedCmp || !isSignedExt)
- return 0;
+ return nullptr;
// Evaluate the comparison for LT (we invert for GT below). LE and GE cases
// should have been folded away previously and not enter in here.
// In order to eliminate the add-with-constant, the compare can be its only
// use.
Instruction *AddWithCst = cast<Instruction>(I.getOperand(0));
- if (!AddWithCst->hasOneUse()) return 0;
+ if (!AddWithCst->hasOneUse()) return nullptr;
// If CI2 is 2^7, 2^15, 2^31, then it might be an sadd.with.overflow.
- if (!CI2->getValue().isPowerOf2()) return 0;
+ if (!CI2->getValue().isPowerOf2()) return nullptr;
unsigned NewWidth = CI2->getValue().countTrailingZeros();
- if (NewWidth != 7 && NewWidth != 15 && NewWidth != 31) return 0;
+ if (NewWidth != 7 && NewWidth != 15 && NewWidth != 31) return nullptr;
// The width of the new add formed is 1 more than the bias.
++NewWidth;
// Check to see that CI1 is an all-ones value with NewWidth bits.
if (CI1->getBitWidth() == NewWidth ||
CI1->getValue() != APInt::getLowBitsSet(CI1->getBitWidth(), NewWidth))
- return 0;
+ return nullptr;
// This is only really a signed overflow check if the inputs have been
// sign-extended; check for that condition. For example, if CI2 is 2^31 and
// the operands of the add are 64 bits wide, we need at least 33 sign bits.
unsigned NeededSignBits = CI1->getBitWidth() - NewWidth + 1;
- if (IC.ComputeNumSignBits(A) < NeededSignBits ||
- IC.ComputeNumSignBits(B) < NeededSignBits)
- return 0;
+ if (IC.ComputeNumSignBits(A, 0, &I) < NeededSignBits ||
+ IC.ComputeNumSignBits(B, 0, &I) < NeededSignBits)
+ return nullptr;
// In order to replace the original add with a narrower
// llvm.sadd.with.overflow, the only uses allowed are the add-with-constant
// original add had another add which was then immediately truncated, we
// could still do the transformation.
TruncInst *TI = dyn_cast<TruncInst>(U);
- if (TI == 0 ||
- TI->getType()->getPrimitiveSizeInBits() > NewWidth) return 0;
+ if (!TI || TI->getType()->getPrimitiveSizeInBits() > NewWidth)
+ return nullptr;
}
// If the pattern matches, truncate the inputs to the narrower type and
InstCombiner &IC) {
// Don't bother doing this transformation for pointers, don't do it for
// vectors.
- if (!isa<IntegerType>(OrigAddV->getType())) return 0;
+ if (!isa<IntegerType>(OrigAddV->getType())) return nullptr;
// If the add is a constant expr, then we don't bother transforming it.
Instruction *OrigAdd = dyn_cast<Instruction>(OrigAddV);
- if (OrigAdd == 0) return 0;
+ if (!OrigAdd) return nullptr;
Value *LHS = OrigAdd->getOperand(0), *RHS = OrigAdd->getOperand(1);
/// replacement required.
static Instruction *ProcessUMulZExtIdiom(ICmpInst &I, Value *MulVal,
Value *OtherVal, InstCombiner &IC) {
+ // Don't bother doing this transformation for pointers, don't do it for
+ // vectors.
+ if (!isa<IntegerType>(MulVal->getType()))
+ return nullptr;
+
assert(I.getOperand(0) == MulVal || I.getOperand(1) == MulVal);
assert(I.getOperand(0) == OtherVal || I.getOperand(1) == OtherVal);
- assert(isa<IntegerType>(MulVal->getType()));
Instruction *MulInstr = cast<Instruction>(MulVal);
assert(MulInstr->getOpcode() == Instruction::Mul);
- Instruction *LHS = cast<Instruction>(MulInstr->getOperand(0)),
- *RHS = cast<Instruction>(MulInstr->getOperand(1));
+ auto *LHS = cast<ZExtOperator>(MulInstr->getOperand(0)),
+ *RHS = cast<ZExtOperator>(MulInstr->getOperand(1));
assert(LHS->getOpcode() == Instruction::ZExt);
assert(RHS->getOpcode() == Instruction::ZExt);
Value *A = LHS->getOperand(0), *B = RHS->getOperand(0);
// Check if truncation ignores bits above MulWidth.
unsigned TruncWidth = TI->getType()->getPrimitiveSizeInBits();
if (TruncWidth > MulWidth)
- return 0;
+ return nullptr;
} else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(U)) {
// Check if AND ignores bits above MulWidth.
if (BO->getOpcode() != Instruction::And)
- return 0;
+ return nullptr;
if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(1))) {
const APInt &CVal = CI->getValue();
if (CVal.getBitWidth() - CVal.countLeadingZeros() > MulWidth)
- return 0;
+ return nullptr;
}
} else {
// Other uses prohibit this transformation.
- return 0;
+ return nullptr;
}
}
Value *ValToMask;
if (match(OtherVal, m_And(m_Value(ValToMask), m_ConstantInt(CI)))) {
if (ValToMask != MulVal)
- return 0;
+ return nullptr;
const APInt &CVal = CI->getValue() + 1;
if (CVal.isPowerOf2()) {
unsigned MaskWidth = CVal.logBase2();
break; // Recognized
}
}
- return 0;
+ return nullptr;
case ICmpInst::ICMP_UGT:
// Recognize pattern:
if (MaxVal.eq(CI->getValue()))
break; // Recognized
}
- return 0;
+ return nullptr;
case ICmpInst::ICMP_UGE:
// Recognize pattern:
if (MaxVal.eq(CI->getValue()))
break; // Recognized
}
- return 0;
+ return nullptr;
case ICmpInst::ICMP_ULE:
// Recognize pattern:
if (MaxVal.eq(CI->getValue()))
break; // Recognized
}
- return 0;
+ return nullptr;
case ICmpInst::ICMP_ULT:
// Recognize pattern:
// mulval = mul(zext A, zext B)
// cmp ule mulval, max + 1
if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) {
- APInt MaxVal(CI->getBitWidth(), 1ULL << MulWidth);
+ APInt MaxVal = APInt::getOneBitSet(CI->getBitWidth(), MulWidth);
if (MaxVal.eq(CI->getValue()))
break; // Recognized
}
- return 0;
+ return nullptr;
default:
- return 0;
+ return nullptr;
}
InstCombiner::BuilderTy *Builder = IC.Builder;
// If there are uses of mul result other than the comparison, we know that
// they are truncation or binary AND. Change them to use result of
- // mul.with.overflow and ajust properly mask/size.
+ // mul.with.overflow and adjust properly mask/size.
if (MulVal->hasNUsesOrMore(2)) {
Value *Mul = Builder->CreateExtractValue(Call, 0, "umul.value");
for (User *U : MulVal->users()) {
Changed = true;
}
- if (Value *V = SimplifyICmpInst(I.getPredicate(), Op0, Op1, DL))
+ if (Value *V = SimplifyICmpInst(I.getPredicate(), Op0, Op1, DL, TLI, DT, AT))
return ReplaceInstUsesWith(I, V);
// comparing -val or val with non-zero is the same as just comparing val
// See if we are doing a comparison with a constant.
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
- Value *A = 0, *B = 0;
+ Value *A = nullptr, *B = nullptr;
// Match the following pattern, which is a common idiom when writing
// overflow-safe integer arithmetic function. The source performs an
Builder->getInt(CI->getValue()-1));
}
+ if (I.isEquality()) {
+ ConstantInt *CI2;
+ if (match(Op0, m_AShr(m_ConstantInt(CI2), m_Value(A))) ||
+ match(Op0, m_LShr(m_ConstantInt(CI2), m_Value(A)))) {
+ // (icmp eq/ne (ashr/lshr const2, A), const1)
+ if (Instruction *Inst = FoldICmpCstShrCst(I, Op0, A, CI, CI2))
+ return Inst;
+ }
+ if (match(Op0, m_Shl(m_ConstantInt(CI2), m_Value(A)))) {
+ // (icmp eq/ne (shl const2, A), const1)
+ if (Instruction *Inst = FoldICmpCstShlCst(I, Op0, A, CI, CI2))
+ return Inst;
+ }
+ }
+
// If this comparison is a normal comparison, it demands all
// bits, if it is a sign bit comparison, it only demands the sign bit.
bool UnusedBit;
// bit is set. If the comparison is against zero, then this is a check
// to see if *that* bit is set.
APInt Op0KnownZeroInverted = ~Op0KnownZero;
- if (~Op1KnownZero == 0 && Op0KnownZeroInverted.isPowerOf2()) {
+ if (~Op1KnownZero == 0) {
// If the LHS is an AND with the same constant, look through it.
- Value *LHS = 0;
- ConstantInt *LHSC = 0;
+ Value *LHS = nullptr;
+ ConstantInt *LHSC = nullptr;
if (!match(Op0, m_And(m_Value(LHS), m_ConstantInt(LHSC))) ||
LHSC->getValue() != Op0KnownZeroInverted)
LHS = Op0;
// If the LHS is 1 << x, and we know the result is a power of 2 like 8,
// then turn "((1 << x)&8) == 0" into "x != 3".
- Value *X = 0;
+ // or turn "((1 << x)&7) == 0" into "x > 2".
+ Value *X = nullptr;
if (match(LHS, m_Shl(m_One(), m_Value(X)))) {
- unsigned CmpVal = Op0KnownZeroInverted.countTrailingZeros();
- return new ICmpInst(ICmpInst::ICMP_NE, X,
- ConstantInt::get(X->getType(), CmpVal));
+ APInt ValToCheck = Op0KnownZeroInverted;
+ if (ValToCheck.isPowerOf2()) {
+ unsigned CmpVal = ValToCheck.countTrailingZeros();
+ return new ICmpInst(ICmpInst::ICMP_NE, X,
+ ConstantInt::get(X->getType(), CmpVal));
+ } else if ((++ValToCheck).isPowerOf2()) {
+ unsigned CmpVal = ValToCheck.countTrailingZeros() - 1;
+ return new ICmpInst(ICmpInst::ICMP_UGT, X,
+ ConstantInt::get(X->getType(), CmpVal));
+ }
}
// If the LHS is 8 >>u x, and we know the result is a power of 2 like 1,
// bit is set. If the comparison is against zero, then this is a check
// to see if *that* bit is set.
APInt Op0KnownZeroInverted = ~Op0KnownZero;
- if (~Op1KnownZero == 0 && Op0KnownZeroInverted.isPowerOf2()) {
+ if (~Op1KnownZero == 0) {
// If the LHS is an AND with the same constant, look through it.
- Value *LHS = 0;
- ConstantInt *LHSC = 0;
+ Value *LHS = nullptr;
+ ConstantInt *LHSC = nullptr;
if (!match(Op0, m_And(m_Value(LHS), m_ConstantInt(LHSC))) ||
LHSC->getValue() != Op0KnownZeroInverted)
LHS = Op0;
// If the LHS is 1 << x, and we know the result is a power of 2 like 8,
// then turn "((1 << x)&8) != 0" into "x == 3".
- Value *X = 0;
+ // or turn "((1 << x)&7) != 0" into "x < 3".
+ Value *X = nullptr;
if (match(LHS, m_Shl(m_One(), m_Value(X)))) {
- unsigned CmpVal = Op0KnownZeroInverted.countTrailingZeros();
- return new ICmpInst(ICmpInst::ICMP_EQ, X,
- ConstantInt::get(X->getType(), CmpVal));
+ APInt ValToCheck = Op0KnownZeroInverted;
+ if (ValToCheck.isPowerOf2()) {
+ unsigned CmpVal = ValToCheck.countTrailingZeros();
+ return new ICmpInst(ICmpInst::ICMP_EQ, X,
+ ConstantInt::get(X->getType(), CmpVal));
+ } else if ((++ValToCheck).isPowerOf2()) {
+ unsigned CmpVal = ValToCheck.countTrailingZeros();
+ return new ICmpInst(ICmpInst::ICMP_ULT, X,
+ ConstantInt::get(X->getType(), CmpVal));
+ }
}
// If the LHS is 8 >>u x, and we know the result is a power of 2 like 1,
if (SelectInst *SI = dyn_cast<SelectInst>(*I.user_begin()))
if ((SI->getOperand(1) == Op0 && SI->getOperand(2) == Op1) ||
(SI->getOperand(2) == Op0 && SI->getOperand(1) == Op1))
- return 0;
+ return nullptr;
// See if we are doing a comparison between a constant and an instruction that
// can be folded into the comparison.
// If either operand of the select is a constant, we can fold the
// comparison into the select arms, which will cause one to be
// constant folded and the select turned into a bitwise or.
- Value *Op1 = 0, *Op2 = 0;
+ Value *Op1 = nullptr, *Op2 = nullptr;
if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(1)))
Op1 = ConstantExpr::getICmp(I.getPredicate(), C, RHSC);
if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(2)))
// Analyze the case when either Op0 or Op1 is an add instruction.
// Op0 = A + B (or A and B are null); Op1 = C + D (or C and D are null).
- Value *A = 0, *B = 0, *C = 0, *D = 0;
+ Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
if (BO0 && BO0->getOpcode() == Instruction::Add)
A = BO0->getOperand(0), B = BO0->getOperand(1);
if (BO1 && BO1->getOpcode() == Instruction::Add)
C = BO1->getOperand(0), D = BO1->getOperand(1);
+ // icmp (X+cst) < 0 --> X < -cst
+ if (NoOp0WrapProblem && ICmpInst::isSigned(Pred) && match(Op1, m_Zero()))
+ if (ConstantInt *RHSC = dyn_cast_or_null<ConstantInt>(B))
+ if (!RHSC->isMinValue(/*isSigned=*/true))
+ return new ICmpInst(Pred, A, ConstantExpr::getNeg(RHSC));
+
// icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
if ((A == Op1 || B == Op1) && NoOp0WrapProblem)
return new ICmpInst(Pred, A == Op1 ? B : A,
// Analyze the case when either Op0 or Op1 is a sub instruction.
// Op0 = A - B (or A and B are null); Op1 = C - D (or C and D are null).
- A = 0; B = 0; C = 0; D = 0;
+ A = nullptr; B = nullptr; C = nullptr; D = nullptr;
if (BO0 && BO0->getOpcode() == Instruction::Sub)
A = BO0->getOperand(0), B = BO0->getOperand(1);
if (BO1 && BO1->getOpcode() == Instruction::Sub)
BO0->hasOneUse() && BO1->hasOneUse())
return new ICmpInst(Pred, D, B);
- BinaryOperator *SRem = NULL;
+ // icmp (0-X) < cst --> x > -cst
+ if (NoOp0WrapProblem && ICmpInst::isSigned(Pred)) {
+ Value *X;
+ if (match(BO0, m_Neg(m_Value(X))))
+ if (ConstantInt *RHSC = dyn_cast<ConstantInt>(Op1))
+ if (!RHSC->isMinValue(/*isSigned=*/true))
+ return new ICmpInst(I.getSwappedPredicate(), X,
+ ConstantExpr::getNeg(RHSC));
+ }
+
+ BinaryOperator *SRem = nullptr;
// icmp (srem X, Y), Y
if (BO0 && BO0->getOpcode() == Instruction::SRem &&
Op1 == BO0->getOperand(1))
// and (A & ~B) != 0 --> (A & B) == 0
// if A is a power of 2.
if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) &&
- match(Op1, m_Zero()) && isKnownToBeAPowerOfTwo(A) && I.isEquality())
+ match(Op1, m_Zero()) && isKnownToBeAPowerOfTwo(A, false,
+ 0, AT, &I, DT) &&
+ I.isEquality())
return new ICmpInst(I.getInversePredicate(),
Builder->CreateAnd(A, B),
Op1);
// (X&Z) == (Y&Z) -> (X^Y) & Z == 0
if (match(Op0, m_OneUse(m_And(m_Value(A), m_Value(B)))) &&
match(Op1, m_OneUse(m_And(m_Value(C), m_Value(D))))) {
- Value *X = 0, *Y = 0, *Z = 0;
+ Value *X = nullptr, *Y = nullptr, *Z = nullptr;
if (A == C) {
X = B; Y = D; Z = A;
if (match(Op1, m_Add(m_Value(X), m_ConstantInt(Cst))) && Op0 == X)
return FoldICmpAddOpCst(I, X, Cst, I.getSwappedPredicate());
}
- return Changed ? &I : 0;
+ return Changed ? &I : nullptr;
}
/// FoldFCmp_IntToFP_Cst - Fold fcmp ([us]itofp x, cst) if possible.
Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I,
Instruction *LHSI,
Constant *RHSC) {
- if (!isa<ConstantFP>(RHSC)) return 0;
+ if (!isa<ConstantFP>(RHSC)) return nullptr;
const APFloat &RHS = cast<ConstantFP>(RHSC)->getValueAPF();
// Get the width of the mantissa. We don't want to hack on conversions that
// might lose information from the integer, e.g. "i64 -> float"
int MantissaWidth = LHSI->getType()->getFPMantissaWidth();
- if (MantissaWidth == -1) return 0; // Unknown.
+ if (MantissaWidth == -1) return nullptr; // Unknown.
// Check to see that the input is converted from an integer type that is small
// enough that preserves all bits. TODO: check here for "known" sign bits.
// If the conversion would lose info, don't hack on this.
if ((int)InputSize > MantissaWidth)
- return 0;
+ return nullptr;
// Otherwise, we can potentially simplify the comparison. We know that it
// will always come through as an integer value and we know the constant is
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifyFCmpInst(I.getPredicate(), Op0, Op1, DL))
+ if (Value *V = SimplifyFCmpInst(I.getPredicate(), Op0, Op1, DL, TLI, DT, AT))
return ReplaceInstUsesWith(I, V);
// Simplify 'fcmp pred X, X'
return new FCmpInst(I.getPredicate(), LHSExt->getOperand(0),
RHSExt->getOperand(0));
- return Changed ? &I : 0;
+ return Changed ? &I : nullptr;
}
projects / oota-llvm.git / blobdiff