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[libc][stdbit] implement stdc_first_leading_one (C23) (#81502)

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This commit is contained in:
Nick Desaulniers
2024-02-14 09:16:00 -08:00
committed by GitHub
parent 7c4c274643
commit 60596716c2
24 changed files with 385 additions and 26 deletions
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5
libc/config/linux/x86_64/entrypoints.txt
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@@ -117,6 +117,11 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.stdbit.stdc_first_leading_zero_ui
libc.src.stdbit.stdc_first_leading_zero_ul
libc.src.stdbit.stdc_first_leading_zero_ull
libc.src.stdbit.stdc_first_leading_one_uc
libc.src.stdbit.stdc_first_leading_one_us
libc.src.stdbit.stdc_first_leading_one_ui
libc.src.stdbit.stdc_first_leading_one_ul
libc.src.stdbit.stdc_first_leading_one_ull
# stdlib.h entrypoints
libc.src.stdlib.abs

48
libc/docs/stdbit.rst
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@@ -41,26 +41,26 @@ stdc_leading_ones_us |check|
stdc_leading_ones_ui |check|
stdc_leading_ones_ul |check|
stdc_leading_ones_ull |check|
stdc_trailing_zeros_uc
stdc_trailing_zeros_us
stdc_trailing_zeros_ui
stdc_trailing_zeros_ul
stdc_trailing_zeros_ull
stdc_trailing_ones_uc
stdc_trailing_ones_us
stdc_trailing_ones_ui
stdc_trailing_ones_ul
stdc_trailing_ones_ull
stdc_first_leading_zero_uc
stdc_first_leading_zero_us
stdc_first_leading_zero_ui
stdc_first_leading_zero_ul
stdc_first_leading_zero_ull
stdc_first_leading_one_uc
stdc_first_leading_one_us
stdc_first_leading_one_ui
stdc_first_leading_one_ul
stdc_first_leading_one_ull
stdc_trailing_zeros_uc |check|
stdc_trailing_zeros_us |check|
stdc_trailing_zeros_ui |check|
stdc_trailing_zeros_ul |check|
stdc_trailing_zeros_ull |check|
stdc_trailing_ones_uc |check|
stdc_trailing_ones_us |check|
stdc_trailing_ones_ui |check|
stdc_trailing_ones_ul |check|
stdc_trailing_ones_ull |check|
stdc_first_leading_zero_uc |check|
stdc_first_leading_zero_us |check|
stdc_first_leading_zero_ui |check|
stdc_first_leading_zero_ul |check|
stdc_first_leading_zero_ull |check|
stdc_first_leading_one_uc |check|
stdc_first_leading_one_us |check|
stdc_first_leading_one_ui |check|
stdc_first_leading_one_ul |check|
stdc_first_leading_one_ull |check|
stdc_first_trailing_zero_uc
stdc_first_trailing_zero_us
stdc_first_trailing_zero_ui
@@ -116,10 +116,10 @@ __STDC_ENDIAN_BIG__
__STDC_ENDIAN_NATIVE__
stdc_leading_zeros |check|
stdc_leading_ones |check|
stdc_trailing_zeros
stdc_trailing_ones
stdc_first_leading_zero
stdc_first_leading_one
stdc_trailing_zeros |check|
stdc_trailing_ones |check|
stdc_first_leading_zero |check|
stdc_first_leading_one |check|
stdc_first_trailing_zero
stdc_first_trailing_one
stdc_count_zeros

22
libc/include/llvm-libc-macros/stdbit-macros.h
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@@ -86,6 +86,21 @@ inline unsigned stdc_first_leading_zero(unsigned long x) {
inline unsigned stdc_first_leading_zero(unsigned long long x) {
return stdc_first_leading_zero_ull(x);
}
inline unsigned stdc_first_leading_one(unsigned char x) {
return stdc_first_leading_one_uc(x);
}
inline unsigned stdc_first_leading_one(unsigned short x) {
return stdc_first_leading_one_us(x);
}
inline unsigned stdc_first_leading_one(unsigned x) {
return stdc_first_leading_one_ui(x);
}
inline unsigned stdc_first_leading_one(unsigned long x) {
return stdc_first_leading_one_ul(x);
}
inline unsigned stdc_first_leading_one(unsigned long long x) {
return stdc_first_leading_one_ull(x);
}
#else
#define stdc_leading_zeros(x) \
_Generic((x), \
@@ -122,6 +137,13 @@ inline unsigned stdc_first_leading_zero(unsigned long long x) {
unsigned: stdc_first_leading_zero_ui, \
unsigned long: stdc_first_leading_zero_ul, \
unsigned long long: stdc_first_leading_zero_ull)(x)
#define stdc_first_leading_one(x) \
_Generic((x), \
unsigned char: stdc_first_leading_one_uc, \
unsigned short: stdc_first_leading_one_us, \
unsigned: stdc_first_leading_one_ui, \
unsigned long: stdc_first_leading_one_ul, \
unsigned long long: stdc_first_leading_one_ull)(x)
#endif // __cplusplus
#endif // __LLVM_LIBC_MACROS_STDBIT_MACROS_H

10
libc/spec/stdc.td
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@@ -781,7 +781,8 @@ def StdC : StandardSpec<"stdc"> {
Macro<"stdc_leading_ones">,
Macro<"stdc_trailing_zeros">,
Macro<"stdc_trailing_ones">,
Macro<"stdc_first_leading_zero">
Macro<"stdc_first_leading_zero">,
Macro<"stdc_first_leading_one">
], // Macros
[], // Types
[], // Enumerations
@@ -810,7 +811,12 @@ def StdC : StandardSpec<"stdc"> {
FunctionSpec<"stdc_first_leading_zero_us", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedShortType>]>,
FunctionSpec<"stdc_first_leading_zero_ui", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedIntType>]>,
FunctionSpec<"stdc_first_leading_zero_ul", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongType>]>,
FunctionSpec<"stdc_first_leading_zero_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>
FunctionSpec<"stdc_first_leading_zero_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>,
FunctionSpec<"stdc_first_leading_one_uc", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedCharType>]>,
FunctionSpec<"stdc_first_leading_one_us", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedShortType>]>,
FunctionSpec<"stdc_first_leading_one_ui", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedIntType>]>,
FunctionSpec<"stdc_first_leading_one_ul", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongType>]>,
FunctionSpec<"stdc_first_leading_one_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>
] // Functions
>;

5
libc/src/__support/CPP/bit.h
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@@ -231,6 +231,11 @@ template <typename T, typename = cpp::enable_if_t<cpp::is_unsigned_v<T>>>
return value == cpp::numeric_limits<T>::max() ? 0 : countl_one(value) + 1;
}
template <typename T, typename = cpp::enable_if_t<cpp::is_unsigned_v<T>>>
[[nodiscard]] LIBC_INLINE constexpr int first_leading_one(T value) {
return first_leading_zero(static_cast<T>(~value));
}
} // namespace LIBC_NAMESPACE::cpp
#endif // LLVM_LIBC_SRC___SUPPORT_CPP_BIT_H

1
libc/src/stdbit/CMakeLists.txt
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@@ -4,6 +4,7 @@ set(prefixes
trailing_zeros
trailing_ones
first_leading_zero
first_leading_one
)
set(suffixes c s i l ll)
foreach(prefix IN LISTS prefixes)

20
libc/src/stdbit/stdc_first_leading_one_uc.cpp Normal file
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@@ -0,0 +1,20 @@
//===-- Implementation of stdc_first_leading_one_uc -----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/stdbit/stdc_first_leading_one_uc.h"
#include "src/__support/CPP/bit.h"
#include "src/__support/common.h"
namespace LIBC_NAMESPACE {
LLVM_LIBC_FUNCTION(unsigned, stdc_first_leading_one_uc, (unsigned char value)) {
return static_cast<unsigned>(cpp::first_leading_one(value));
}
} // namespace LIBC_NAMESPACE

18
libc/src/stdbit/stdc_first_leading_one_uc.h Normal file
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@@ -0,0 +1,18 @@
//===-- Implementation header for stdc_first_leading_one_uc -----*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UC_H
#define LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UC_H
namespace LIBC_NAMESPACE {
unsigned stdc_first_leading_one_uc(unsigned char value);
} // namespace LIBC_NAMESPACE
#endif // LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UC_H

20
libc/src/stdbit/stdc_first_leading_one_ui.cpp Normal file
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@@ -0,0 +1,20 @@
//===-- Implementation of stdc_first_leading_one_ui -----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/stdbit/stdc_first_leading_one_ui.h"
#include "src/__support/CPP/bit.h"
#include "src/__support/common.h"
namespace LIBC_NAMESPACE {
LLVM_LIBC_FUNCTION(unsigned, stdc_first_leading_one_ui, (unsigned value)) {
return static_cast<unsigned>(cpp::first_leading_one(value));
}
} // namespace LIBC_NAMESPACE

18
libc/src/stdbit/stdc_first_leading_one_ui.h Normal file
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@@ -0,0 +1,18 @@
//===-- Implementation header for stdc_first_leading_one_ui -----*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UI_H
#define LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UI_H
namespace LIBC_NAMESPACE {
unsigned stdc_first_leading_one_ui(unsigned value);
} // namespace LIBC_NAMESPACE
#endif // LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UI_H

20
libc/src/stdbit/stdc_first_leading_one_ul.cpp Normal file
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@@ -0,0 +1,20 @@
//===-- Implementation of stdc_first_leading_one_ul -----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/stdbit/stdc_first_leading_one_ul.h"
#include "src/__support/CPP/bit.h"
#include "src/__support/common.h"
namespace LIBC_NAMESPACE {
LLVM_LIBC_FUNCTION(unsigned, stdc_first_leading_one_ul, (unsigned long value)) {
return static_cast<unsigned>(cpp::first_leading_one(value));
}
} // namespace LIBC_NAMESPACE

18
libc/src/stdbit/stdc_first_leading_one_ul.h Normal file
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@@ -0,0 +1,18 @@
//===-- Implementation header for stdc_first_leading_one_ul -----*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UL_H
#define LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UL_H
namespace LIBC_NAMESPACE {
unsigned stdc_first_leading_one_ul(unsigned long value);
} // namespace LIBC_NAMESPACE
#endif // LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UL_H

21
libc/src/stdbit/stdc_first_leading_one_ull.cpp Normal file
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@@ -0,0 +1,21 @@
//===-- Implementation of stdc_first_leading_one_ull ----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/stdbit/stdc_first_leading_one_ull.h"
#include "src/__support/CPP/bit.h"
#include "src/__support/common.h"
namespace LIBC_NAMESPACE {
LLVM_LIBC_FUNCTION(unsigned, stdc_first_leading_one_ull,
(unsigned long long value)) {
return static_cast<unsigned>(cpp::first_leading_one(value));
}
} // namespace LIBC_NAMESPACE

18
libc/src/stdbit/stdc_first_leading_one_ull.h Normal file
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@@ -0,0 +1,18 @@
//===-- Implementation header for stdc_first_leading_one_ull ----*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_ULL_H
#define LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_ULL_H
namespace LIBC_NAMESPACE {
unsigned stdc_first_leading_one_ull(unsigned long long value);
} // namespace LIBC_NAMESPACE
#endif // LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_ULL_H

21
libc/src/stdbit/stdc_first_leading_one_us.cpp Normal file
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@@ -0,0 +1,21 @@
//===-- Implementation of stdc_first_leading_one_us -----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/stdbit/stdc_first_leading_one_us.h"
#include "src/__support/CPP/bit.h"
#include "src/__support/common.h"
namespace LIBC_NAMESPACE {
LLVM_LIBC_FUNCTION(unsigned, stdc_first_leading_one_us,
(unsigned short value)) {
return static_cast<unsigned>(cpp::first_leading_one(value));
}
} // namespace LIBC_NAMESPACE

18
libc/src/stdbit/stdc_first_leading_one_us.h Normal file
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@@ -0,0 +1,18 @@
//===-- Implementation header for stdc_first_leading_one_us -----*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_US_H
#define LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_US_H
namespace LIBC_NAMESPACE {
unsigned stdc_first_leading_one_us(unsigned short value);
} // namespace LIBC_NAMESPACE
#endif // LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_US_H

15
libc/test/include/stdbit_test.cpp
View File

@@ -50,6 +50,13 @@ unsigned stdc_first_leading_zero_ul(unsigned long) noexcept { return 0xEDU; }
unsigned stdc_first_leading_zero_ull(unsigned long long) noexcept {
return 0xEFU;
}
unsigned stdc_first_leading_one_uc(unsigned char) noexcept { return 0xFAU; }
unsigned stdc_first_leading_one_us(unsigned short) noexcept { return 0xFBU; }
unsigned stdc_first_leading_one_ui(unsigned) noexcept { return 0xFCU; }
unsigned stdc_first_leading_one_ul(unsigned long) noexcept { return 0xFDU; }
unsigned stdc_first_leading_one_ull(unsigned long long) noexcept {
return 0xFFU;
}
}
#include "include/llvm-libc-macros/stdbit-macros.h"
@@ -93,3 +100,11 @@ TEST(LlvmLibcStdbitTest, TypeGenericMacroFirstLeadingZero) {
EXPECT_EQ(stdc_first_leading_zero(0UL), 0xEDU);
EXPECT_EQ(stdc_first_leading_zero(0ULL), 0xEFU);
}
TEST(LlvmLibcStdbitTest, TypeGenericMacroFirstLeadingOne) {
EXPECT_EQ(stdc_first_leading_one(static_cast<unsigned char>(0U)), 0xFAU);
EXPECT_EQ(stdc_first_leading_one(static_cast<unsigned short>(0U)), 0xFBU);
EXPECT_EQ(stdc_first_leading_one(0U), 0xFCU);
EXPECT_EQ(stdc_first_leading_one(0UL), 0xFDU);
EXPECT_EQ(stdc_first_leading_one(0ULL), 0xFFU);
}

7
libc/test/src/__support/CPP/bit_test.cpp
View File

@@ -213,4 +213,11 @@ TYPED_TEST(LlvmLibcBitTest, FirstLeadingZero, UnsignedTypes) {
cpp::numeric_limits<T>::digits - i);
}
TYPED_TEST(LlvmLibcBitTest, FirstLeadingOne, UnsignedTypes) {
EXPECT_EQ(first_leading_one<T>(static_cast<T>(0)), 0);
for (int i = 0U; i != cpp::numeric_limits<T>::digits; ++i)
EXPECT_EQ(first_leading_one<T>(T(1) << i),
cpp::numeric_limits<T>::digits - i);
}
} // namespace LIBC_NAMESPACE::cpp

1
libc/test/src/stdbit/CMakeLists.txt
View File

@@ -6,6 +6,7 @@ set(prefixes
trailing_zeros
trailing_ones
first_leading_zero
first_leading_one
)
set(suffixes c s i l ll)
foreach(prefix IN LISTS prefixes)

21
libc/test/src/stdbit/stdc_first_leading_one_uc_test.cpp Normal file
View File

@@ -0,0 +1,21 @@
//===-- Unittests for stdc_first_leading_one_uc ---------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/__support/CPP/limits.h"
#include "src/stdbit/stdc_first_leading_one_uc.h"
#include "test/UnitTest/Test.h"
TEST(LlvmLibcStdcFirstLeadingOneUcTest, Zero) {
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_uc(0U), 0U);
}
TEST(LlvmLibcStdcFirstLeadingOneUcTest, OneHot) {
for (unsigned i = 0U; i != UCHAR_WIDTH; ++i)
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_uc(1U << i),
UCHAR_WIDTH - i);
}

21
libc/test/src/stdbit/stdc_first_leading_one_ui_test.cpp Normal file
View File

@@ -0,0 +1,21 @@
//===-- Unittests for stdc_first_leading_one_ui ---------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/__support/CPP/limits.h"
#include "src/stdbit/stdc_first_leading_one_ui.h"
#include "test/UnitTest/Test.h"
TEST(LlvmLibcStdcFirstLeadingOneUiTest, Zero) {
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_ui(0U), 0U);
}
TEST(LlvmLibcStdcFirstLeadingOneUiTest, OneHot) {
for (unsigned i = 0U; i != UINT_WIDTH; ++i)
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_ui(1U << i),
UINT_WIDTH - i);
}

21
libc/test/src/stdbit/stdc_first_leading_one_ul_test.cpp Normal file
View File

@@ -0,0 +1,21 @@
//===-- Unittests for stdc_first_leading_one_ul ---------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/__support/CPP/limits.h"
#include "src/stdbit/stdc_first_leading_one_ul.h"
#include "test/UnitTest/Test.h"
TEST(LlvmLibcStdcFirstLeadingOneUlTest, Zero) {
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_ul(0UL), 0U);
}
TEST(LlvmLibcStdcFirstLeadingOneUlTest, OneHot) {
for (unsigned i = 0U; i != ULONG_WIDTH; ++i)
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_ul(1UL << i),
ULONG_WIDTH - i);
}

21
libc/test/src/stdbit/stdc_first_leading_one_ull_test.cpp Normal file
View File

@@ -0,0 +1,21 @@
//===-- Unittests for stdc_first_leading_one_ull --------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/__support/CPP/limits.h"
#include "src/stdbit/stdc_first_leading_one_ull.h"
#include "test/UnitTest/Test.h"
TEST(LlvmLibcStdcFirstLeadingOneUllTest, Zero) {
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_ull(0ULL), 0U);
}
TEST(LlvmLibcStdcFirstLeadingOneUllTest, OneHot) {
for (unsigned i = 0U; i != ULLONG_WIDTH; ++i)
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_ull(1ULL << i),
ULLONG_WIDTH - i);
}

21
libc/test/src/stdbit/stdc_first_leading_one_us_test.cpp Normal file
View File

@@ -0,0 +1,21 @@
//===-- Unittests for stdc_first_leading_one_us ---------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "src/__support/CPP/limits.h"
#include "src/stdbit/stdc_first_leading_one_us.h"
#include "test/UnitTest/Test.h"
TEST(LlvmLibcStdcFirstLeadingOneUsTest, Zero) {
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_us(0U), 0U);
}
TEST(LlvmLibcStdcFirstLeadingOneUsTest, OneHot) {
for (unsigned i = 0U; i != USHRT_WIDTH; ++i)
EXPECT_EQ(LIBC_NAMESPACE::stdc_first_leading_one_us(1U << i),
USHRT_WIDTH - i);
}