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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 "gtest/gtest.h"
using namespace llvm;
namespace {
template<typename FnTy>
void ForeachKnownBits(unsigned Bits, FnTy Fn) {
unsigned Max = 1 << Bits;
KnownBits Known(Bits);
for (unsigned Zero = 0; Zero < Max; ++Zero) {
for (unsigned One = 0; One < Max; ++One) {
Known.Zero = Zero;
Known.One = One;
if (Known.hasConflict())
continue;
Fn(Known);
}
}
}
template<typename FnTy>
void ForeachNumInKnownBits(const KnownBits &Known, FnTy Fn) {
unsigned Bits = Known.getBitWidth();
unsigned Max = 1 << Bits;
for (unsigned N = 0; N < Max; ++N) {
APInt Num(Bits, N);
if ((Num & Known.Zero) != 0 || (~Num & Known.One) != 0)
continue;
Fn(Num);
}
}
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);
}
} // end anonymous namespace
|