forked from OSchip/llvm-project
[ConstantRange] Support subtraction in makeGuaranteedNoWrapRegion.
Previously ConstantRange::makeGuaranteedNoWrapRegion only handled addition. This adds support for subtraction. Differential Revision: https://reviews.llvm.org/D40036 llvm-svn: 319806
This commit is contained in:
Joel Galenson
parent
3b4a475c37
commit
c32b0fc249
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@ -96,9 +96,9 @@ public:
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///
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/// NB! The returned set does *not* contain **all** possible values of X for
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/// which "X BinOpC Y" does not wrap -- some viable values of X may be
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/// missing, so you cannot use this to constrain X's range. E.g. in the last
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/// example, "(-2) + 1" is both nsw and nuw (so the "X" could be -2), but (-2)
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/// is not in the set returned.
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/// missing, so you cannot use this to constrain X's range. E.g. in the
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/// fourth example, "(-2) + 1" is both nsw and nuw (so the "X" could be -2),
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/// but (-2) is not in the set returned.
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///
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/// Examples:
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/// typedef OverflowingBinaryOperator OBO;
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@ -109,6 +109,10 @@ public:
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/// MGNR(Add, [i8 1, 2), OBO::NoUnsignedWrap | OBO::NoSignedWrap)
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/// == [0,INT_MAX)
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/// MGNR(Add, [i8 -1, 6), OBO::NoSignedWrap) == [INT_MIN+1, INT_MAX-4)
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/// MGNR(Sub, [i8 1, 2), OBO::NoSignedWrap) == [-127, 128)
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/// MGNR(Sub, [i8 1, 2), OBO::NoUnsignedWrap) == [1, 0)
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/// MGNR(Sub, [i8 1, 2), OBO::NoUnsignedWrap | OBO::NoSignedWrap)
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/// == [1,INT_MAX)
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static ConstantRange makeGuaranteedNoWrapRegion(Instruction::BinaryOps BinOp,
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const ConstantRange &Other,
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unsigned NoWrapKind);
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@ -199,39 +199,63 @@ ConstantRange::makeGuaranteedNoWrapRegion(Instruction::BinaryOps BinOp,
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"NoWrapKind invalid!");
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unsigned BitWidth = Other.getBitWidth();
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if (BinOp != Instruction::Add)
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ConstantRange Result(BitWidth);
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switch (BinOp) {
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default:
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// Conservative answer: empty set
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return ConstantRange(BitWidth, false);
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if (auto *C = Other.getSingleElement())
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if (C->isNullValue())
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// Full set: nothing signed / unsigned wraps when added to 0.
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return ConstantRange(BitWidth);
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case Instruction::Add:
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if (auto *C = Other.getSingleElement())
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if (C->isNullValue())
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// Full set: nothing signed / unsigned wraps when added to 0.
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return ConstantRange(BitWidth);
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if (NoWrapKind & OBO::NoUnsignedWrap)
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Result =
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SubsetIntersect(Result, ConstantRange(APInt::getNullValue(BitWidth),
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-Other.getUnsignedMax()));
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if (NoWrapKind & OBO::NoSignedWrap) {
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const APInt &SignedMin = Other.getSignedMin();
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const APInt &SignedMax = Other.getSignedMax();
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if (SignedMax.isStrictlyPositive())
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Result = SubsetIntersect(
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Result,
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ConstantRange(APInt::getSignedMinValue(BitWidth),
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APInt::getSignedMinValue(BitWidth) - SignedMax));
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if (SignedMin.isNegative())
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Result = SubsetIntersect(
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Result,
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ConstantRange(APInt::getSignedMinValue(BitWidth) - SignedMin,
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APInt::getSignedMinValue(BitWidth)));
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}
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return Result;
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ConstantRange Result(BitWidth);
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if (NoWrapKind & OBO::NoUnsignedWrap)
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Result =
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SubsetIntersect(Result, ConstantRange(APInt::getNullValue(BitWidth),
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-Other.getUnsignedMax()));
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if (NoWrapKind & OBO::NoSignedWrap) {
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const APInt &SignedMin = Other.getSignedMin();
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const APInt &SignedMax = Other.getSignedMax();
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if (SignedMax.isStrictlyPositive())
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Result = SubsetIntersect(
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Result,
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ConstantRange(APInt::getSignedMinValue(BitWidth),
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APInt::getSignedMinValue(BitWidth) - SignedMax));
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if (SignedMin.isNegative())
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Result = SubsetIntersect(
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Result, ConstantRange(APInt::getSignedMinValue(BitWidth) - SignedMin,
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APInt::getSignedMinValue(BitWidth)));
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case Instruction::Sub:
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if (auto *C = Other.getSingleElement())
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if (C->isNullValue())
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// Full set: nothing signed / unsigned wraps when subtracting 0.
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return ConstantRange(BitWidth);
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if (NoWrapKind & OBO::NoUnsignedWrap)
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Result =
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SubsetIntersect(Result, ConstantRange(Other.getUnsignedMax(),
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APInt::getMinValue(BitWidth)));
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if (NoWrapKind & OBO::NoSignedWrap) {
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const APInt &SignedMin = Other.getSignedMin();
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const APInt &SignedMax = Other.getSignedMax();
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if (SignedMax.isStrictlyPositive())
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Result = SubsetIntersect(
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Result,
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ConstantRange(APInt::getSignedMinValue(BitWidth) + SignedMax,
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APInt::getSignedMinValue(BitWidth)));
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if (SignedMin.isNegative())
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Result = SubsetIntersect(
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Result,
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ConstantRange(APInt::getSignedMinValue(BitWidth),
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APInt::getSignedMinValue(BitWidth) + SignedMin));
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}
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return Result;
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}
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return Result;
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}
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bool ConstantRange::isFullSet() const {
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@ -715,24 +715,102 @@ TEST(ConstantRange, MakeGuaranteedNoWrapRegion) {
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}
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}
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for (int Const : {0, -1, -2, 1, 2, IntMin4Bits, IntMax4Bits}) {
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APInt C(4, Const, true /* = isSigned */);
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auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, C, OBO::NoUnsignedWrap);
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EXPECT_FALSE(NUWRegion.isEmptySet());
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auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, C, OBO::NoSignedWrap);
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EXPECT_FALSE(NSWRegion.isEmptySet());
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auto NoWrapRegion = ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, C, OBO::NoSignedWrap | OBO::NoUnsignedWrap);
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EXPECT_FALSE(NoWrapRegion.isEmptySet());
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EXPECT_TRUE(NUWRegion.intersectWith(NSWRegion).contains(NoWrapRegion));
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for (APInt I = NUWRegion.getLower(), E = NUWRegion.getUpper(); I != E;
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++I) {
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bool Overflow = false;
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(void)I.usub_ov(C, Overflow);
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EXPECT_FALSE(Overflow);
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}
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for (APInt I = NSWRegion.getLower(), E = NSWRegion.getUpper(); I != E;
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++I) {
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bool Overflow = false;
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(void)I.ssub_ov(C, Overflow);
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EXPECT_FALSE(Overflow);
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}
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for (APInt I = NoWrapRegion.getLower(), E = NoWrapRegion.getUpper(); I != E;
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++I) {
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bool Overflow = false;
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(void)I.ssub_ov(C, Overflow);
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EXPECT_FALSE(Overflow);
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(void)I.usub_ov(C, Overflow);
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EXPECT_FALSE(Overflow);
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}
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}
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auto NSWForAllValues = ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, ConstantRange(32, /* isFullSet = */ true),
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OBO::NoSignedWrap);
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EXPECT_TRUE(NSWForAllValues.isSingleElement() &&
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NSWForAllValues.getSingleElement()->isMinValue());
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NSWForAllValues = ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, ConstantRange(32, /* isFullSet = */ true),
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OBO::NoSignedWrap);
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EXPECT_TRUE(NSWForAllValues.isSingleElement() &&
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NSWForAllValues.getSingleElement()->isMaxValue());
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auto NUWForAllValues = ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, ConstantRange(32, /* isFullSet = */ true),
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OBO::NoUnsignedWrap);
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EXPECT_TRUE(NUWForAllValues.isSingleElement() &&
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NUWForAllValues.getSingleElement()->isMinValue());
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NUWForAllValues = ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, ConstantRange(32, /* isFullSet = */ true),
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OBO::NoUnsignedWrap);
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EXPECT_TRUE(NUWForAllValues.isSingleElement() &&
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NUWForAllValues.getSingleElement()->isMaxValue());
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auto NUWAndNSWForAllValues = ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, ConstantRange(32, /* isFullSet = */ true),
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OBO::NoUnsignedWrap | OBO::NoSignedWrap);
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EXPECT_TRUE(NUWAndNSWForAllValues.isSingleElement() &&
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NUWAndNSWForAllValues.getSingleElement()->isMinValue());
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NUWAndNSWForAllValues = ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, ConstantRange(32, /* isFullSet = */ true),
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OBO::NoUnsignedWrap | OBO::NoSignedWrap);
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EXPECT_TRUE(NUWAndNSWForAllValues.isSingleElement() &&
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NUWAndNSWForAllValues.getSingleElement()->isMaxValue());
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EXPECT_TRUE(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, APInt(32, 0), OBO::NoUnsignedWrap).isFullSet());
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EXPECT_TRUE(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, APInt(32, 0), OBO::NoSignedWrap).isFullSet());
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EXPECT_TRUE(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, APInt(32, 0),
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OBO::NoUnsignedWrap | OBO::NoSignedWrap).isFullSet());
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EXPECT_TRUE(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, APInt(32, 0), OBO::NoUnsignedWrap).isFullSet());
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EXPECT_TRUE(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, APInt(32, 0), OBO::NoSignedWrap).isFullSet());
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EXPECT_TRUE(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, APInt(32, 0),
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OBO::NoUnsignedWrap | OBO::NoSignedWrap).isFullSet());
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ConstantRange OneToFive(APInt(32, 1), APInt(32, 6));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, OneToFive, OBO::NoSignedWrap),
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@ -745,6 +823,17 @@ TEST(ConstantRange, MakeGuaranteedNoWrapRegion) {
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ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, OneToFive, OBO::NoUnsignedWrap | OBO::NoSignedWrap),
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ConstantRange(APInt::getMinValue(32), APInt::getSignedMaxValue(32) - 4));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, OneToFive, OBO::NoSignedWrap),
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ConstantRange(APInt::getSignedMinValue(32) + 5,
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APInt::getSignedMinValue(32)));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, OneToFive, OBO::NoUnsignedWrap),
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ConstantRange(APInt::getMinValue(32) + 5, APInt::getMinValue(32)));
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EXPECT_EQ(
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ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, OneToFive, OBO::NoUnsignedWrap | OBO::NoSignedWrap),
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ConstantRange(APInt::getMinValue(32) + 5, APInt::getSignedMinValue(32)));
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ConstantRange MinusFiveToMinusTwo(APInt(32, -5), APInt(32, -1));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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@ -758,6 +847,19 @@ TEST(ConstantRange, MakeGuaranteedNoWrapRegion) {
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Instruction::Add, MinusFiveToMinusTwo,
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OBO::NoUnsignedWrap | OBO::NoSignedWrap),
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ConstantRange(APInt(32, 0), APInt(32, 2)));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, MinusFiveToMinusTwo, OBO::NoSignedWrap),
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ConstantRange(APInt::getSignedMinValue(32),
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APInt::getSignedMaxValue(32) - 4));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, MinusFiveToMinusTwo, OBO::NoUnsignedWrap),
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ConstantRange(APInt::getMaxValue(32) - 1,
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APInt::getMinValue(32)));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, MinusFiveToMinusTwo,
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OBO::NoUnsignedWrap | OBO::NoSignedWrap),
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ConstantRange(APInt::getMaxValue(32) - 1,
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APInt::getMinValue(32)));
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ConstantRange MinusOneToOne(APInt(32, -1), APInt(32, 2));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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@ -771,6 +873,43 @@ TEST(ConstantRange, MakeGuaranteedNoWrapRegion) {
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Instruction::Add, MinusOneToOne,
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OBO::NoUnsignedWrap | OBO::NoSignedWrap),
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ConstantRange(APInt(32, 0), APInt(32, 1)));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, MinusOneToOne, OBO::NoSignedWrap),
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ConstantRange(APInt::getSignedMinValue(32) + 1,
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APInt::getSignedMinValue(32) - 1));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, MinusOneToOne, OBO::NoUnsignedWrap),
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ConstantRange(APInt::getMaxValue(32),
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APInt::getMinValue(32)));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, MinusOneToOne,
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OBO::NoUnsignedWrap | OBO::NoSignedWrap),
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ConstantRange(APInt::getMaxValue(32),
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APInt::getMinValue(32)));
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ConstantRange One(APInt(32, 1), APInt(32, 2));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, One, OBO::NoSignedWrap),
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ConstantRange(APInt::getSignedMinValue(32),
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APInt::getSignedMaxValue(32)));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, One, OBO::NoUnsignedWrap),
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ConstantRange(APInt::getMinValue(32), APInt::getMaxValue(32)));
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EXPECT_EQ(
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ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Add, One, OBO::NoUnsignedWrap | OBO::NoSignedWrap),
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ConstantRange(APInt(32, 0), APInt::getSignedMaxValue(32)));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, One, OBO::NoSignedWrap),
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ConstantRange(APInt::getSignedMinValue(32) + 1,
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APInt::getSignedMinValue(32)));
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EXPECT_EQ(ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, One, OBO::NoUnsignedWrap),
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ConstantRange(APInt::getMinValue(32) + 1, APInt::getMinValue(32)));
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EXPECT_EQ(
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ConstantRange::makeGuaranteedNoWrapRegion(
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Instruction::Sub, One, OBO::NoUnsignedWrap | OBO::NoSignedWrap),
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ConstantRange(APInt::getMinValue(32) + 1, APInt::getSignedMinValue(32)));
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}
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TEST(ConstantRange, GetEquivalentICmp) {
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