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nickdesaulniersnickdesaulniers
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[libc][stdbit] implement stdc_first_leading_one (C23) (#81502)
1 parent 7c4c274 commit 6059671

24 files changed

+385
-26
lines changed

‎libc/config/linux/x86_64/entrypoints.txt‎

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@@ -117,6 +117,11 @@ set(TARGET_LIBC_ENTRYPOINTS
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libc.src.stdbit.stdc_first_leading_zero_ui
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libc.src.stdbit.stdc_first_leading_zero_ul
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libc.src.stdbit.stdc_first_leading_zero_ull
120+
libc.src.stdbit.stdc_first_leading_one_uc
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libc.src.stdbit.stdc_first_leading_one_us
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libc.src.stdbit.stdc_first_leading_one_ui
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libc.src.stdbit.stdc_first_leading_one_ul
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libc.src.stdbit.stdc_first_leading_one_ull
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# stdlib.h entrypoints
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libc.src.stdlib.abs

‎libc/docs/stdbit.rst‎

Lines changed: 24 additions & 24 deletions
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@@ -41,26 +41,26 @@ stdc_leading_ones_us |check|
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stdc_leading_ones_ui |check|
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stdc_leading_ones_ul |check|
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stdc_leading_ones_ull |check|
44-
stdc_trailing_zeros_uc
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stdc_trailing_zeros_us
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stdc_trailing_zeros_ui
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stdc_trailing_zeros_ul
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stdc_trailing_zeros_ull
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stdc_trailing_ones_uc
50-
stdc_trailing_ones_us
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stdc_trailing_ones_ui
52-
stdc_trailing_ones_ul
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stdc_trailing_ones_ull
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stdc_first_leading_zero_uc
55-
stdc_first_leading_zero_us
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stdc_first_leading_zero_ui
57-
stdc_first_leading_zero_ul
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stdc_first_leading_zero_ull
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stdc_first_leading_one_uc
60-
stdc_first_leading_one_us
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stdc_first_leading_one_ui
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stdc_first_leading_one_ul
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stdc_first_leading_one_ull
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stdc_trailing_zeros_uc |check|
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stdc_trailing_zeros_us |check|
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stdc_trailing_zeros_ui |check|
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stdc_trailing_zeros_ul |check|
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stdc_trailing_zeros_ull |check|
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stdc_trailing_ones_uc |check|
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stdc_trailing_ones_us |check|
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stdc_trailing_ones_ui |check|
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stdc_trailing_ones_ul |check|
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stdc_trailing_ones_ull |check|
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stdc_first_leading_zero_uc |check|
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stdc_first_leading_zero_us |check|
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stdc_first_leading_zero_ui |check|
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stdc_first_leading_zero_ul |check|
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stdc_first_leading_zero_ull |check|
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stdc_first_leading_one_uc |check|
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stdc_first_leading_one_us |check|
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stdc_first_leading_one_ui |check|
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stdc_first_leading_one_ul |check|
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stdc_first_leading_one_ull |check|
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stdc_first_trailing_zero_uc
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stdc_first_trailing_zero_us
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stdc_first_trailing_zero_ui
@@ -116,10 +116,10 @@ __STDC_ENDIAN_BIG__
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__STDC_ENDIAN_NATIVE__
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stdc_leading_zeros |check|
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stdc_leading_ones |check|
119-
stdc_trailing_zeros
120-
stdc_trailing_ones
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stdc_first_leading_zero
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stdc_first_leading_one
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stdc_trailing_zeros |check|
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stdc_trailing_ones |check|
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stdc_first_leading_zero |check|
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stdc_first_leading_one |check|
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stdc_first_trailing_zero
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stdc_first_trailing_one
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stdc_count_zeros

‎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) {
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inline unsigned stdc_first_leading_zero(unsigned long long x) {
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return stdc_first_leading_zero_ull(x);
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}
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inline unsigned stdc_first_leading_one(unsigned char x) {
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return stdc_first_leading_one_uc(x);
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}
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inline unsigned stdc_first_leading_one(unsigned short x) {
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return stdc_first_leading_one_us(x);
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}
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inline unsigned stdc_first_leading_one(unsigned x) {
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return stdc_first_leading_one_ui(x);
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}
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inline unsigned stdc_first_leading_one(unsigned long x) {
99+
return stdc_first_leading_one_ul(x);
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}
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inline unsigned stdc_first_leading_one(unsigned long long x) {
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return stdc_first_leading_one_ull(x);
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}
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#else
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#define stdc_leading_zeros(x) \
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_Generic((x), \
@@ -122,6 +137,13 @@ inline unsigned stdc_first_leading_zero(unsigned long long x) {
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unsigned: stdc_first_leading_zero_ui, \
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unsigned long: stdc_first_leading_zero_ul, \
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unsigned long long: stdc_first_leading_zero_ull)(x)
140+
#define stdc_first_leading_one(x) \
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_Generic((x), \
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unsigned char: stdc_first_leading_one_uc, \
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unsigned short: stdc_first_leading_one_us, \
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unsigned: stdc_first_leading_one_ui, \
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unsigned long: stdc_first_leading_one_ul, \
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unsigned long long: stdc_first_leading_one_ull)(x)
125147
#endif // __cplusplus
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127149
#endif // __LLVM_LIBC_MACROS_STDBIT_MACROS_H

‎libc/spec/stdc.td‎

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@@ -781,7 +781,8 @@ def StdC : StandardSpec<"stdc"> {
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Macro<"stdc_leading_ones">,
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Macro<"stdc_trailing_zeros">,
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Macro<"stdc_trailing_ones">,
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Macro<"stdc_first_leading_zero">
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Macro<"stdc_first_leading_zero">,
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Macro<"stdc_first_leading_one">
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], // Macros
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[], // Types
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[], // Enumerations
@@ -810,7 +811,12 @@ def StdC : StandardSpec<"stdc"> {
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FunctionSpec<"stdc_first_leading_zero_us", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedShortType>]>,
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FunctionSpec<"stdc_first_leading_zero_ui", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedIntType>]>,
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FunctionSpec<"stdc_first_leading_zero_ul", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongType>]>,
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FunctionSpec<"stdc_first_leading_zero_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>
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FunctionSpec<"stdc_first_leading_zero_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>,
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FunctionSpec<"stdc_first_leading_one_uc", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedCharType>]>,
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FunctionSpec<"stdc_first_leading_one_us", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedShortType>]>,
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FunctionSpec<"stdc_first_leading_one_ui", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedIntType>]>,
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FunctionSpec<"stdc_first_leading_one_ul", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongType>]>,
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FunctionSpec<"stdc_first_leading_one_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>
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] // Functions
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>;
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‎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>>>
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return value == cpp::numeric_limits<T>::max() ? 0 : countl_one(value) + 1;
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}
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234+
template <typename T, typename = cpp::enable_if_t<cpp::is_unsigned_v<T>>>
235+
[[nodiscard]] LIBC_INLINE constexpr int first_leading_one(T value) {
236+
return first_leading_zero(static_cast<T>(~value));
237+
}
238+
234239
} // namespace LIBC_NAMESPACE::cpp
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236241
#endif // LLVM_LIBC_SRC___SUPPORT_CPP_BIT_H

‎libc/src/stdbit/CMakeLists.txt‎

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@@ -4,6 +4,7 @@ set(prefixes
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trailing_zeros
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trailing_ones
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first_leading_zero
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first_leading_one
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)
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set(suffixes c s i l ll)
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foreach(prefix IN LISTS prefixes)

‎libc/src/stdbit/stdc_first_leading_one_uc.cpp‎

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@@ -0,0 +1,20 @@
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//===-- Implementation of stdc_first_leading_one_uc -----------------------===//
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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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#include "src/stdbit/stdc_first_leading_one_uc.h"
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11+
#include "src/__support/CPP/bit.h"
12+
#include "src/__support/common.h"
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namespace LIBC_NAMESPACE {
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16+
LLVM_LIBC_FUNCTION(unsigned, stdc_first_leading_one_uc, (unsigned char value)) {
17+
return static_cast<unsigned>(cpp::first_leading_one(value));
18+
}
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} // namespace LIBC_NAMESPACE

‎libc/src/stdbit/stdc_first_leading_one_uc.h‎

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//===-- Implementation header for stdc_first_leading_one_uc -----*- C++ -*-===//
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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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#ifndef LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UC_H
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#define LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UC_H
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12+
namespace LIBC_NAMESPACE {
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14+
unsigned stdc_first_leading_one_uc(unsigned char value);
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} // namespace LIBC_NAMESPACE
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#endif // LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UC_H

‎libc/src/stdbit/stdc_first_leading_one_ui.cpp‎

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@@ -0,0 +1,20 @@
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//===-- Implementation of stdc_first_leading_one_ui -----------------------===//
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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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#include "src/stdbit/stdc_first_leading_one_ui.h"
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11+
#include "src/__support/CPP/bit.h"
12+
#include "src/__support/common.h"
13+
14+
namespace LIBC_NAMESPACE {
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16+
LLVM_LIBC_FUNCTION(unsigned, stdc_first_leading_one_ui, (unsigned value)) {
17+
return static_cast<unsigned>(cpp::first_leading_one(value));
18+
}
19+
20+
} // namespace LIBC_NAMESPACE

‎libc/src/stdbit/stdc_first_leading_one_ui.h‎

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@@ -0,0 +1,18 @@
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//===-- Implementation header for stdc_first_leading_one_ui -----*- C++ -*-===//
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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.
5+
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UI_H
10+
#define LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UI_H
11+
12+
namespace LIBC_NAMESPACE {
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14+
unsigned stdc_first_leading_one_ui(unsigned value);
15+
16+
} // namespace LIBC_NAMESPACE
17+
18+
#endif // LLVM_LIBC_SRC_STDBIT_STDC_FIRST_LEADING_ONE_UI_H

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