return nullptr;
}
+static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
+ Value *RHS) {
+ // FIXME: Use m_APInt here and below to allow splat vector folds.
+ ConstantInt *CI = dyn_cast<ConstantInt>(RHS);
+ if (!CI)
+ return nullptr;
+
+ // Rule out tautological comparisons (eg., ult 0 or uge 0).
+ ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
+ if (RHS_CR.isEmptySet())
+ return ConstantInt::getFalse(CI->getContext());
+ if (RHS_CR.isFullSet())
+ return ConstantInt::getTrue(CI->getContext());
+
+ // Many binary operators with constant RHS have easy to compute constant
+ // range. Use them to check whether the comparison is a tautology.
+ unsigned Width = CI->getBitWidth();
+ APInt Lower = APInt(Width, 0);
+ APInt Upper = APInt(Width, 0);
+ ConstantInt *CI2;
+ if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
+ // 'urem x, CI2' produces [0, CI2).
+ Upper = CI2->getValue();
+ } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
+ // 'srem x, CI2' produces (-|CI2|, |CI2|).
+ Upper = CI2->getValue().abs();
+ Lower = (-Upper) + 1;
+ } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
+ // 'udiv CI2, x' produces [0, CI2].
+ Upper = CI2->getValue() + 1;
+ } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
+ // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
+ APInt NegOne = APInt::getAllOnesValue(Width);
+ if (!CI2->isZero())
+ Upper = NegOne.udiv(CI2->getValue()) + 1;
+ } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
+ if (CI2->isMinSignedValue()) {
+ // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
+ Lower = CI2->getValue();
+ Upper = Lower.lshr(1) + 1;
+ } else {
+ // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
+ Upper = CI2->getValue().abs() + 1;
+ Lower = (-Upper) + 1;
+ }
+ } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
+ APInt IntMin = APInt::getSignedMinValue(Width);
+ APInt IntMax = APInt::getSignedMaxValue(Width);
+ const APInt &Val = CI2->getValue();
+ if (Val.isAllOnesValue()) {
+ // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
+ // where CI2 != -1 and CI2 != 0 and CI2 != 1
+ Lower = IntMin + 1;
+ Upper = IntMax + 1;
+ } else if (Val.countLeadingZeros() < Width - 1) {
+ // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]
+ // where CI2 != -1 and CI2 != 0 and CI2 != 1
+ Lower = IntMin.sdiv(Val);
+ Upper = IntMax.sdiv(Val);
+ if (Lower.sgt(Upper))
+ std::swap(Lower, Upper);
+ Upper = Upper + 1;
+ assert(Upper != Lower && "Upper part of range has wrapped!");
+ }
+ } else if (match(LHS, m_NUWShl(m_ConstantInt(CI2), m_Value()))) {
+ // 'shl nuw CI2, x' produces [CI2, CI2 << CLZ(CI2)]
+ Lower = CI2->getValue();
+ Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
+ } else if (match(LHS, m_NSWShl(m_ConstantInt(CI2), m_Value()))) {
+ if (CI2->isNegative()) {
+ // 'shl nsw CI2, x' produces [CI2 << CLO(CI2)-1, CI2]
+ unsigned ShiftAmount = CI2->getValue().countLeadingOnes() - 1;
+ Lower = CI2->getValue().shl(ShiftAmount);
+ Upper = CI2->getValue() + 1;
+ } else {
+ // 'shl nsw CI2, x' produces [CI2, CI2 << CLZ(CI2)-1]
+ unsigned ShiftAmount = CI2->getValue().countLeadingZeros() - 1;
+ Lower = CI2->getValue();
+ Upper = CI2->getValue().shl(ShiftAmount) + 1;
+ }
+ } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
+ // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
+ APInt NegOne = APInt::getAllOnesValue(Width);
+ if (CI2->getValue().ult(Width))
+ Upper = NegOne.lshr(CI2->getValue()) + 1;
+ } else if (match(LHS, m_LShr(m_ConstantInt(CI2), m_Value()))) {
+ // 'lshr CI2, x' produces [CI2 >> (Width-1), CI2].
+ unsigned ShiftAmount = Width - 1;
+ if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
+ ShiftAmount = CI2->getValue().countTrailingZeros();
+ Lower = CI2->getValue().lshr(ShiftAmount);
+ Upper = CI2->getValue() + 1;
+ } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
+ // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
+ APInt IntMin = APInt::getSignedMinValue(Width);
+ APInt IntMax = APInt::getSignedMaxValue(Width);
+ if (CI2->getValue().ult(Width)) {
+ Lower = IntMin.ashr(CI2->getValue());
+ Upper = IntMax.ashr(CI2->getValue()) + 1;
+ }
+ } else if (match(LHS, m_AShr(m_ConstantInt(CI2), m_Value()))) {
+ unsigned ShiftAmount = Width - 1;
+ if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
+ ShiftAmount = CI2->getValue().countTrailingZeros();
+ if (CI2->isNegative()) {
+ // 'ashr CI2, x' produces [CI2, CI2 >> (Width-1)]
+ Lower = CI2->getValue();
+ Upper = CI2->getValue().ashr(ShiftAmount) + 1;
+ } else {
+ // 'ashr CI2, x' produces [CI2 >> (Width-1), CI2]
+ Lower = CI2->getValue().ashr(ShiftAmount);
+ Upper = CI2->getValue() + 1;
+ }
+ } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
+ // 'or x, CI2' produces [CI2, UINT_MAX].
+ Lower = CI2->getValue();
+ } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
+ // 'and x, CI2' produces [0, CI2].
+ Upper = CI2->getValue() + 1;
+ } else if (match(LHS, m_NUWAdd(m_Value(), m_ConstantInt(CI2)))) {
+ // 'add nuw x, CI2' produces [CI2, UINT_MAX].
+ Lower = CI2->getValue();
+ }
+
+ ConstantRange LHS_CR =
+ Lower != Upper ? ConstantRange(Lower, Upper) : ConstantRange(Width, true);
+
+ if (auto *I = dyn_cast<Instruction>(LHS))
+ if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
+ LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));
+
+ if (!LHS_CR.isFullSet()) {
+ if (RHS_CR.contains(LHS_CR))
+ return ConstantInt::getTrue(RHS->getContext());
+ if (RHS_CR.inverse().contains(LHS_CR))
+ return ConstantInt::getFalse(RHS->getContext());
+ }
+
+ return nullptr;
+}
+
/// Given operands for an ICmpInst, see if we can fold the result.
/// If not, this returns null.
static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
}
}
- // See if we are doing a comparison with a constant integer.
- if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
- // Rule out tautological comparisons (eg., ult 0 or uge 0).
- ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
- if (RHS_CR.isEmptySet())
- return ConstantInt::getFalse(CI->getContext());
- if (RHS_CR.isFullSet())
- return ConstantInt::getTrue(CI->getContext());
-
- // Many binary operators with constant RHS have easy to compute constant
- // range. Use them to check whether the comparison is a tautology.
- unsigned Width = CI->getBitWidth();
- APInt Lower = APInt(Width, 0);
- APInt Upper = APInt(Width, 0);
- ConstantInt *CI2;
- if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
- // 'urem x, CI2' produces [0, CI2).
- Upper = CI2->getValue();
- } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
- // 'srem x, CI2' produces (-|CI2|, |CI2|).
- Upper = CI2->getValue().abs();
- Lower = (-Upper) + 1;
- } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
- // 'udiv CI2, x' produces [0, CI2].
- Upper = CI2->getValue() + 1;
- } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
- // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
- APInt NegOne = APInt::getAllOnesValue(Width);
- if (!CI2->isZero())
- Upper = NegOne.udiv(CI2->getValue()) + 1;
- } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
- if (CI2->isMinSignedValue()) {
- // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
- Lower = CI2->getValue();
- Upper = Lower.lshr(1) + 1;
- } else {
- // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
- Upper = CI2->getValue().abs() + 1;
- Lower = (-Upper) + 1;
- }
- } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
- APInt IntMin = APInt::getSignedMinValue(Width);
- APInt IntMax = APInt::getSignedMaxValue(Width);
- const APInt &Val = CI2->getValue();
- if (Val.isAllOnesValue()) {
- // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
- // where CI2 != -1 and CI2 != 0 and CI2 != 1
- Lower = IntMin + 1;
- Upper = IntMax + 1;
- } else if (Val.countLeadingZeros() < Width - 1) {
- // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]
- // where CI2 != -1 and CI2 != 0 and CI2 != 1
- Lower = IntMin.sdiv(Val);
- Upper = IntMax.sdiv(Val);
- if (Lower.sgt(Upper))
- std::swap(Lower, Upper);
- Upper = Upper + 1;
- assert(Upper != Lower && "Upper part of range has wrapped!");
- }
- } else if (match(LHS, m_NUWShl(m_ConstantInt(CI2), m_Value()))) {
- // 'shl nuw CI2, x' produces [CI2, CI2 << CLZ(CI2)]
- Lower = CI2->getValue();
- Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
- } else if (match(LHS, m_NSWShl(m_ConstantInt(CI2), m_Value()))) {
- if (CI2->isNegative()) {
- // 'shl nsw CI2, x' produces [CI2 << CLO(CI2)-1, CI2]
- unsigned ShiftAmount = CI2->getValue().countLeadingOnes() - 1;
- Lower = CI2->getValue().shl(ShiftAmount);
- Upper = CI2->getValue() + 1;
- } else {
- // 'shl nsw CI2, x' produces [CI2, CI2 << CLZ(CI2)-1]
- unsigned ShiftAmount = CI2->getValue().countLeadingZeros() - 1;
- Lower = CI2->getValue();
- Upper = CI2->getValue().shl(ShiftAmount) + 1;
- }
- } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
- // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
- APInt NegOne = APInt::getAllOnesValue(Width);
- if (CI2->getValue().ult(Width))
- Upper = NegOne.lshr(CI2->getValue()) + 1;
- } else if (match(LHS, m_LShr(m_ConstantInt(CI2), m_Value()))) {
- // 'lshr CI2, x' produces [CI2 >> (Width-1), CI2].
- unsigned ShiftAmount = Width - 1;
- if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
- ShiftAmount = CI2->getValue().countTrailingZeros();
- Lower = CI2->getValue().lshr(ShiftAmount);
- Upper = CI2->getValue() + 1;
- } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
- // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
- APInt IntMin = APInt::getSignedMinValue(Width);
- APInt IntMax = APInt::getSignedMaxValue(Width);
- if (CI2->getValue().ult(Width)) {
- Lower = IntMin.ashr(CI2->getValue());
- Upper = IntMax.ashr(CI2->getValue()) + 1;
- }
- } else if (match(LHS, m_AShr(m_ConstantInt(CI2), m_Value()))) {
- unsigned ShiftAmount = Width - 1;
- if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
- ShiftAmount = CI2->getValue().countTrailingZeros();
- if (CI2->isNegative()) {
- // 'ashr CI2, x' produces [CI2, CI2 >> (Width-1)]
- Lower = CI2->getValue();
- Upper = CI2->getValue().ashr(ShiftAmount) + 1;
- } else {
- // 'ashr CI2, x' produces [CI2 >> (Width-1), CI2]
- Lower = CI2->getValue().ashr(ShiftAmount);
- Upper = CI2->getValue() + 1;
- }
- } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
- // 'or x, CI2' produces [CI2, UINT_MAX].
- Lower = CI2->getValue();
- } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
- // 'and x, CI2' produces [0, CI2].
- Upper = CI2->getValue() + 1;
- } else if (match(LHS, m_NUWAdd(m_Value(), m_ConstantInt(CI2)))) {
- // 'add nuw x, CI2' produces [CI2, UINT_MAX].
- Lower = CI2->getValue();
- }
-
- ConstantRange LHS_CR = Lower != Upper ? ConstantRange(Lower, Upper)
- : ConstantRange(Width, true);
-
- if (auto *I = dyn_cast<Instruction>(LHS))
- if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
- LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));
-
- if (!LHS_CR.isFullSet()) {
- if (RHS_CR.contains(LHS_CR))
- return ConstantInt::getTrue(RHS->getContext());
- if (RHS_CR.inverse().contains(LHS_CR))
- return ConstantInt::getFalse(RHS->getContext());
- }
- }
+ if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS))
+ return V;
// If both operands have range metadata, use the metadata
// to simplify the comparison.