forked from OSchip/llvm-project
131 lines
3.8 KiB
C++
131 lines
3.8 KiB
C++
//===- llvm/unittest/Support/KnownBitsTest.cpp - KnownBits tests ----------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements unit tests for KnownBits functions.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/KnownBits.h"
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#include "gtest/gtest.h"
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using namespace llvm;
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namespace {
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template<typename FnTy>
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void ForeachKnownBits(unsigned Bits, FnTy Fn) {
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unsigned Max = 1 << Bits;
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KnownBits Known(Bits);
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for (unsigned Zero = 0; Zero < Max; ++Zero) {
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for (unsigned One = 0; One < Max; ++One) {
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Known.Zero = Zero;
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Known.One = One;
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if (Known.hasConflict())
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continue;
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Fn(Known);
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}
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}
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}
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template<typename FnTy>
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void ForeachNumInKnownBits(const KnownBits &Known, FnTy Fn) {
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unsigned Bits = Known.getBitWidth();
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unsigned Max = 1 << Bits;
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for (unsigned N = 0; N < Max; ++N) {
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APInt Num(Bits, N);
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if ((Num & Known.Zero) != 0 || (~Num & Known.One) != 0)
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continue;
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Fn(Num);
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}
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}
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TEST(KnownBitsTest, AddCarryExhaustive) {
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unsigned Bits = 4;
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ForeachKnownBits(Bits, [&](const KnownBits &Known1) {
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ForeachKnownBits(Bits, [&](const KnownBits &Known2) {
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ForeachKnownBits(1, [&](const KnownBits &KnownCarry) {
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// Explicitly compute known bits of the addition by trying all
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// possibilities.
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KnownBits Known(Bits);
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Known.Zero.setAllBits();
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Known.One.setAllBits();
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ForeachNumInKnownBits(Known1, [&](const APInt &N1) {
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ForeachNumInKnownBits(Known2, [&](const APInt &N2) {
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ForeachNumInKnownBits(KnownCarry, [&](const APInt &Carry) {
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APInt Add = N1 + N2;
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if (Carry.getBoolValue())
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++Add;
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Known.One &= Add;
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Known.Zero &= ~Add;
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});
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});
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});
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KnownBits KnownComputed = KnownBits::computeForAddCarry(
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Known1, Known2, KnownCarry);
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EXPECT_EQ(Known.Zero, KnownComputed.Zero);
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EXPECT_EQ(Known.One, KnownComputed.One);
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});
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});
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});
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}
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static void TestAddSubExhaustive(bool IsAdd) {
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unsigned Bits = 4;
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ForeachKnownBits(Bits, [&](const KnownBits &Known1) {
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ForeachKnownBits(Bits, [&](const KnownBits &Known2) {
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KnownBits Known(Bits), KnownNSW(Bits);
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Known.Zero.setAllBits();
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Known.One.setAllBits();
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KnownNSW.Zero.setAllBits();
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KnownNSW.One.setAllBits();
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ForeachNumInKnownBits(Known1, [&](const APInt &N1) {
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ForeachNumInKnownBits(Known2, [&](const APInt &N2) {
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bool Overflow;
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APInt Res;
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if (IsAdd)
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Res = N1.sadd_ov(N2, Overflow);
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else
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Res = N1.ssub_ov(N2, Overflow);
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Known.One &= Res;
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Known.Zero &= ~Res;
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if (!Overflow) {
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KnownNSW.One &= Res;
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KnownNSW.Zero &= ~Res;
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}
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});
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});
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KnownBits KnownComputed = KnownBits::computeForAddSub(
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IsAdd, /*NSW*/false, Known1, Known2);
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EXPECT_EQ(Known.Zero, KnownComputed.Zero);
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EXPECT_EQ(Known.One, KnownComputed.One);
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// The NSW calculation is not precise, only check that it's
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// conservatively correct.
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KnownBits KnownNSWComputed = KnownBits::computeForAddSub(
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IsAdd, /*NSW*/true, Known1, Known2);
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EXPECT_TRUE(KnownNSWComputed.Zero.isSubsetOf(KnownNSW.Zero));
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EXPECT_TRUE(KnownNSWComputed.One.isSubsetOf(KnownNSW.One));
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});
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});
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}
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TEST(KnownBitsTest, AddSubExhaustive) {
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TestAddSubExhaustive(true);
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TestAddSubExhaustive(false);
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}
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} // end anonymous namespace
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