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//===- llvm/unittest/Support/KnownBitsTest.cpp - KnownBits tests ----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements unit tests for KnownBits functions.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/KnownBits.h"
#include "KnownBitsTest.h"
#include "gtest/gtest.h"
using namespace llvm;
namespace {
TEST(KnownBitsTest, AddCarryExhaustive) {
unsigned Bits = 4;
ForeachKnownBits(Bits, [&](const KnownBits &Known1) {
ForeachKnownBits(Bits, [&](const KnownBits &Known2) {
ForeachKnownBits(1, [&](const KnownBits &KnownCarry) {
// Explicitly compute known bits of the addition by trying all
// possibilities.
KnownBits Known(Bits);
Known.Zero.setAllBits();
Known.One.setAllBits();
ForeachNumInKnownBits(Known1, [&](const APInt &N1) {
ForeachNumInKnownBits(Known2, [&](const APInt &N2) {
ForeachNumInKnownBits(KnownCarry, [&](const APInt &Carry) {
APInt Add = N1 + N2;
if (Carry.getBoolValue())
++Add;
Known.One &= Add;
Known.Zero &= ~Add;
});
});
});
KnownBits KnownComputed = KnownBits::computeForAddCarry(
Known1, Known2, KnownCarry);
EXPECT_EQ(Known.Zero, KnownComputed.Zero);
EXPECT_EQ(Known.One, KnownComputed.One);
});
});
});
}
static void TestAddSubExhaustive(bool IsAdd) {
unsigned Bits = 4;
ForeachKnownBits(Bits, [&](const KnownBits &Known1) {
ForeachKnownBits(Bits, [&](const KnownBits &Known2) {
KnownBits Known(Bits), KnownNSW(Bits);
Known.Zero.setAllBits();
Known.One.setAllBits();
KnownNSW.Zero.setAllBits();
KnownNSW.One.setAllBits();
ForeachNumInKnownBits(Known1, [&](const APInt &N1) {
ForeachNumInKnownBits(Known2, [&](const APInt &N2) {
bool Overflow;
APInt Res;
if (IsAdd)
Res = N1.sadd_ov(N2, Overflow);
else
Res = N1.ssub_ov(N2, Overflow);
Known.One &= Res;
Known.Zero &= ~Res;
if (!Overflow) {
KnownNSW.One &= Res;
KnownNSW.Zero &= ~Res;
}
});
});
KnownBits KnownComputed = KnownBits::computeForAddSub(
IsAdd, /*NSW*/false, Known1, Known2);
EXPECT_EQ(Known.Zero, KnownComputed.Zero);
EXPECT_EQ(Known.One, KnownComputed.One);
// The NSW calculation is not precise, only check that it's
// conservatively correct.
KnownBits KnownNSWComputed = KnownBits::computeForAddSub(
IsAdd, /*NSW*/true, Known1, Known2);
EXPECT_TRUE(KnownNSWComputed.Zero.isSubsetOf(KnownNSW.Zero));
EXPECT_TRUE(KnownNSWComputed.One.isSubsetOf(KnownNSW.One));
});
});
}
TEST(KnownBitsTest, AddSubExhaustive) {
TestAddSubExhaustive(true);
TestAddSubExhaustive(false);
}
TEST(KnownBitsTest, BinaryExhaustive) {
unsigned Bits = 4;
ForeachKnownBits(Bits, [&](const KnownBits &Known1) {
ForeachKnownBits(Bits, [&](const KnownBits &Known2) {
KnownBits KnownAnd(Bits);
KnownAnd.Zero.setAllBits();
KnownAnd.One.setAllBits();
KnownBits KnownOr(KnownAnd);
KnownBits KnownXor(KnownAnd);
KnownBits KnownUMax(KnownAnd);
KnownBits KnownUMin(KnownAnd);
KnownBits KnownSMax(KnownAnd);
KnownBits KnownSMin(KnownAnd);
KnownBits KnownMul(KnownAnd);
KnownBits KnownUDiv(KnownAnd);
KnownBits KnownURem(KnownAnd);
KnownBits KnownSRem(KnownAnd);
KnownBits KnownShl(KnownAnd);
KnownBits KnownLShr(KnownAnd);
KnownBits KnownAShr(KnownAnd);
ForeachNumInKnownBits(Known1, [&](const APInt &N1) {
ForeachNumInKnownBits(Known2, [&](const APInt &N2) {
APInt Res;
Res = N1 & N2;
KnownAnd.One &= Res;
KnownAnd.Zero &= ~Res;
Res = N1 | N2;
KnownOr.One &= Res;
KnownOr.Zero &= ~Res;
Res = N1 ^ N2;
KnownXor.One &= Res;
KnownXor.Zero &= ~Res;
Res = APIntOps::umax(N1, N2);
KnownUMax.One &= Res;
KnownUMax.Zero &= ~Res;
Res = APIntOps::umin(N1, N2);
KnownUMin.One &= Res;
KnownUMin.Zero &= ~Res;
Res = APIntOps::smax(N1, N2);
KnownSMax.One &= Res;
KnownSMax.Zero &= ~Res;
Res = APIntOps::smin(N1, N2);
KnownSMin.One &= Res;
KnownSMin.Zero &= ~Res;
Res = N1 * N2;
KnownMul.One &= Res;
KnownMul.Zero &= ~Res;
if (!N2.isNullValue()) {
Res = N1.udiv(N2);
KnownUDiv.One &= Res;
KnownUDiv.Zero &= ~Res;
Res = N1.urem(N2);
KnownURem.One &= Res;
KnownURem.Zero &= ~Res;
Res = N1.srem(N2);
KnownSRem.One &= Res;
KnownSRem.Zero &= ~Res;
}
if (N2.ult(1ULL << N1.getBitWidth())) {
Res = N1.shl(N2);
KnownShl.One &= Res;
KnownShl.Zero &= ~Res;
Res = N1.lshr(N2);
KnownLShr.One &= Res;
KnownLShr.Zero &= ~Res;
Res = N1.ashr(N2);
KnownAShr.One &= Res;
KnownAShr.Zero &= ~Res;
} else {
KnownShl.resetAll();
KnownLShr.resetAll();
KnownAShr.resetAll();
}
});
});
KnownBits ComputedAnd = Known1 & Known2;
EXPECT_EQ(KnownAnd.Zero, ComputedAnd.Zero);
EXPECT_EQ(KnownAnd.One, ComputedAnd.One);
KnownBits ComputedOr = Known1 | Known2;
EXPECT_EQ(KnownOr.Zero, ComputedOr.Zero);
EXPECT_EQ(KnownOr.One, ComputedOr.One);
KnownBits ComputedXor = Known1 ^ Known2;
EXPECT_EQ(KnownXor.Zero, ComputedXor.Zero);
EXPECT_EQ(KnownXor.One, ComputedXor.One);
KnownBits ComputedUMax = KnownBits::umax(Known1, Known2);
EXPECT_EQ(KnownUMax.Zero, ComputedUMax.Zero);
EXPECT_EQ(KnownUMax.One, ComputedUMax.One);
KnownBits ComputedUMin = KnownBits::umin(Known1, Known2);
EXPECT_EQ(KnownUMin.Zero, ComputedUMin.Zero);
EXPECT_EQ(KnownUMin.One, ComputedUMin.One);
KnownBits ComputedSMax = KnownBits::smax(Known1, Known2);
EXPECT_EQ(KnownSMax.Zero, ComputedSMax.Zero);
EXPECT_EQ(KnownSMax.One, ComputedSMax.One);
KnownBits ComputedSMin = KnownBits::smin(Known1, Known2);
EXPECT_EQ(KnownSMin.Zero, ComputedSMin.Zero);
EXPECT_EQ(KnownSMin.One, ComputedSMin.One);
// ComputedMul is conservatively correct, but not guaranteed to be
// precise.
KnownBits ComputedMul = KnownBits::computeForMul(Known1, Known2);
EXPECT_TRUE(ComputedMul.Zero.isSubsetOf(KnownMul.Zero));
EXPECT_TRUE(ComputedMul.One.isSubsetOf(KnownMul.One));
KnownBits ComputedUDiv = KnownBits::udiv(Known1, Known2);
EXPECT_TRUE(ComputedUDiv.Zero.isSubsetOf(KnownUDiv.Zero));
EXPECT_TRUE(ComputedUDiv.One.isSubsetOf(KnownUDiv.One));
KnownBits ComputedURem = KnownBits::urem(Known1, Known2);
EXPECT_TRUE(ComputedURem.Zero.isSubsetOf(KnownURem.Zero));
EXPECT_TRUE(ComputedURem.One.isSubsetOf(KnownURem.One));
KnownBits ComputedSRem = KnownBits::srem(Known1, Known2);
EXPECT_TRUE(ComputedSRem.Zero.isSubsetOf(KnownSRem.Zero));
EXPECT_TRUE(ComputedSRem.One.isSubsetOf(KnownSRem.One));
KnownBits ComputedShl = KnownBits::shl(Known1, Known2);
EXPECT_TRUE(ComputedShl.Zero.isSubsetOf(KnownShl.Zero));
EXPECT_TRUE(ComputedShl.One.isSubsetOf(KnownShl.One));
KnownBits ComputedLShr = KnownBits::lshr(Known1, Known2);
EXPECT_TRUE(ComputedLShr.Zero.isSubsetOf(KnownLShr.Zero));
EXPECT_TRUE(ComputedLShr.One.isSubsetOf(KnownLShr.One));
KnownBits ComputedAShr = KnownBits::ashr(Known1, Known2);
EXPECT_TRUE(ComputedAShr.Zero.isSubsetOf(KnownAShr.Zero));
EXPECT_TRUE(ComputedAShr.One.isSubsetOf(KnownAShr.One));
});
});
}
TEST(KnownBitsTest, UnaryExhaustive) {
unsigned Bits = 4;
ForeachKnownBits(Bits, [&](const KnownBits &Known) {
KnownBits KnownAbs(Bits);
KnownAbs.Zero.setAllBits();
KnownAbs.One.setAllBits();
KnownBits KnownAbsPoison(KnownAbs);
ForeachNumInKnownBits(Known, [&](const APInt &N) {
APInt Res = N.abs();
KnownAbs.One &= Res;
KnownAbs.Zero &= ~Res;
if (!N.isMinSignedValue()) {
KnownAbsPoison.One &= Res;
KnownAbsPoison.Zero &= ~Res;
}
});
// abs() is conservatively correct, but not guaranteed to be precise.
KnownBits ComputedAbs = Known.abs();
EXPECT_TRUE(ComputedAbs.Zero.isSubsetOf(KnownAbs.Zero));
EXPECT_TRUE(ComputedAbs.One.isSubsetOf(KnownAbs.One));
KnownBits ComputedAbsPoison = Known.abs(true);
EXPECT_TRUE(ComputedAbsPoison.Zero.isSubsetOf(KnownAbsPoison.Zero));
EXPECT_TRUE(ComputedAbsPoison.One.isSubsetOf(KnownAbsPoison.One));
});
}
TEST(KnownBitsTest, GetMinMaxVal) {
unsigned Bits = 4;
ForeachKnownBits(Bits, [&](const KnownBits &Known) {
APInt Min = APInt::getMaxValue(Bits);
APInt Max = APInt::getMinValue(Bits);
ForeachNumInKnownBits(Known, [&](const APInt &N) {
Min = APIntOps::umin(Min, N);
Max = APIntOps::umax(Max, N);
});
EXPECT_EQ(Min, Known.getMinValue());
EXPECT_EQ(Max, Known.getMaxValue());
});
}
TEST(KnownBitsTest, SExtOrTrunc) {
const unsigned NarrowerSize = 4;
const unsigned BaseSize = 6;
const unsigned WiderSize = 8;
APInt NegativeFitsNarrower(BaseSize, -4, /*isSigned*/ true);
APInt NegativeDoesntFitNarrower(BaseSize, -28, /*isSigned*/ true);
APInt PositiveFitsNarrower(BaseSize, 14);
APInt PositiveDoesntFitNarrower(BaseSize, 36);
auto InitKnownBits = [&](KnownBits &Res, const APInt &Input) {
Res = KnownBits(Input.getBitWidth());
Res.One = Input;
Res.Zero = ~Input;
};
for (unsigned Size : {NarrowerSize, BaseSize, WiderSize}) {
for (const APInt &Input :
{NegativeFitsNarrower, NegativeDoesntFitNarrower, PositiveFitsNarrower,
PositiveDoesntFitNarrower}) {
KnownBits Test;
InitKnownBits(Test, Input);
KnownBits Baseline;
InitKnownBits(Baseline, Input.sextOrTrunc(Size));
Test = Test.sextOrTrunc(Size);
EXPECT_EQ(Test.One, Baseline.One);
EXPECT_EQ(Test.Zero, Baseline.Zero);
}
}
}
} // end anonymous namespace