[libc-commits] [libc] trailing ones (PR #80459)

via libc-commits libc-commits at lists.llvm.org
Fri Feb 2 08:26:44 PST 2024


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: Nick Desaulniers (nickdesaulniers)

<details>
<summary>Changes</summary>

- [libc][stdbit] implement stdc_trailing_zeros (C23)
- format
- refactor cmake; getting tired of writing these already
- s/LLONG_WIDTH/ULLONG_WIDTH/
- update stdc.td
- [libc][stdbit] implement stdc_trailing_ones (C23)


---

Patch is 40.52 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/80459.diff


35 Files Affected:

- (modified) libc/config/linux/x86_64/entrypoints.txt (+10) 
- (modified) libc/include/llvm-libc-macros/stdbit-macros.h (+44) 
- (modified) libc/spec/stdc.td (+11-1) 
- (modified) libc/src/stdbit/CMakeLists.txt (+20-99) 
- (added) libc/src/stdbit/stdc_trailing_ones_uc.cpp (+20) 
- (added) libc/src/stdbit/stdc_trailing_ones_uc.h (+18) 
- (added) libc/src/stdbit/stdc_trailing_ones_ui.cpp (+20) 
- (added) libc/src/stdbit/stdc_trailing_ones_ui.h (+18) 
- (added) libc/src/stdbit/stdc_trailing_ones_ul.cpp (+20) 
- (added) libc/src/stdbit/stdc_trailing_ones_ul.h (+18) 
- (added) libc/src/stdbit/stdc_trailing_ones_ull.cpp (+20) 
- (added) libc/src/stdbit/stdc_trailing_ones_ull.h (+18) 
- (added) libc/src/stdbit/stdc_trailing_ones_us.cpp (+20) 
- (added) libc/src/stdbit/stdc_trailing_ones_us.h (+18) 
- (added) libc/src/stdbit/stdc_trailing_zeros_uc.cpp (+20) 
- (added) libc/src/stdbit/stdc_trailing_zeros_uc.h (+18) 
- (added) libc/src/stdbit/stdc_trailing_zeros_ui.cpp (+20) 
- (added) libc/src/stdbit/stdc_trailing_zeros_ui.h (+18) 
- (added) libc/src/stdbit/stdc_trailing_zeros_ul.cpp (+20) 
- (added) libc/src/stdbit/stdc_trailing_zeros_ul.h (+18) 
- (added) libc/src/stdbit/stdc_trailing_zeros_ull.cpp (+21) 
- (added) libc/src/stdbit/stdc_trailing_zeros_ull.h (+18) 
- (added) libc/src/stdbit/stdc_trailing_zeros_us.cpp (+20) 
- (added) libc/src/stdbit/stdc_trailing_zeros_us.h (+18) 
- (modified) libc/test/include/stdbit_test.cpp (+26) 
- (modified) libc/test/src/stdbit/CMakeLists.txt (+21-110) 
- (added) libc/test/src/stdbit/stdc_trailing_ones_uc_test.cpp (+21) 
- (added) libc/test/src/stdbit/stdc_trailing_ones_ui_test.cpp (+21) 
- (added) libc/test/src/stdbit/stdc_trailing_ones_ul_test.cpp (+21) 
- (added) libc/test/src/stdbit/stdc_trailing_ones_us_test.cpp (+21) 
- (added) libc/test/src/stdbit/stdc_trailing_zeros_uc_test.cpp (+21) 
- (added) libc/test/src/stdbit/stdc_trailing_zeros_ui_test.cpp (+21) 
- (added) libc/test/src/stdbit/stdc_trailing_zeros_ul_test.cpp (+21) 
- (added) libc/test/src/stdbit/stdc_trailing_zeros_ull_test.cpp (+21) 
- (added) libc/test/src/stdbit/stdc_trailing_zeros_us_test.cpp (+21) 


``````````diff
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 9946b93c346ce..82c40a5cbcc06 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -102,6 +102,16 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdbit.stdc_leading_ones_ui
     libc.src.stdbit.stdc_leading_ones_ul
     libc.src.stdbit.stdc_leading_ones_ull
+    libc.src.stdbit.stdc_trailing_zeros_uc
+    libc.src.stdbit.stdc_trailing_zeros_us
+    libc.src.stdbit.stdc_trailing_zeros_ui
+    libc.src.stdbit.stdc_trailing_zeros_ul
+    libc.src.stdbit.stdc_trailing_zeros_ull
+    libc.src.stdbit.stdc_trailing_ones_uc
+    libc.src.stdbit.stdc_trailing_ones_us
+    libc.src.stdbit.stdc_trailing_ones_ui
+    libc.src.stdbit.stdc_trailing_ones_ul
+    libc.src.stdbit.stdc_trailing_ones_ull
 
     # stdlib.h entrypoints
     libc.src.stdlib.abs
diff --git a/libc/include/llvm-libc-macros/stdbit-macros.h b/libc/include/llvm-libc-macros/stdbit-macros.h
index cc964a5268b0d..840246b795635 100644
--- a/libc/include/llvm-libc-macros/stdbit-macros.h
+++ b/libc/include/llvm-libc-macros/stdbit-macros.h
@@ -40,6 +40,36 @@ inline unsigned stdc_leading_ones(unsigned long x) {
 inline unsigned stdc_leading_ones(unsigned long long x) {
   return stdc_leading_ones_ull(x);
 }
+inline unsigned stdc_trailing_zeros(unsigned char x) {
+  return stdc_trailing_zeros_uc(x);
+}
+inline unsigned stdc_trailing_zeros(unsigned short x) {
+  return stdc_trailing_zeros_us(x);
+}
+inline unsigned stdc_trailing_zeros(unsigned x) {
+  return stdc_trailing_zeros_ui(x);
+}
+inline unsigned stdc_trailing_zeros(unsigned long x) {
+  return stdc_trailing_zeros_ul(x);
+}
+inline unsigned stdc_trailing_zeros(unsigned long long x) {
+  return stdc_trailing_zeros_ull(x);
+}
+inline unsigned stdc_trailing_ones(unsigned char x) {
+  return stdc_trailing_ones_uc(x);
+}
+inline unsigned stdc_trailing_ones(unsigned short x) {
+  return stdc_trailing_ones_us(x);
+}
+inline unsigned stdc_trailing_ones(unsigned x) {
+  return stdc_trailing_ones_ui(x);
+}
+inline unsigned stdc_trailing_ones(unsigned long x) {
+  return stdc_trailing_ones_ul(x);
+}
+inline unsigned stdc_trailing_ones(unsigned long long x) {
+  return stdc_trailing_ones_ull(x);
+}
 #else
 #define stdc_leading_zeros(x)                                                  \
   _Generic((x),                                                                \
@@ -55,6 +85,20 @@ inline unsigned stdc_leading_ones(unsigned long long x) {
       unsigned: stdc_leading_ones_ui,                                          \
       unsigned long: stdc_leading_ones_ul,                                     \
       unsigned long long: stdc_leading_ones_ull)(x)
+#define stdc_trailing_zeros(x)                                                 \
+  _Generic((x),                                                                \
+      unsigned char: stdc_trailing_zeros_uc,                                   \
+      unsigned short: stdc_trailing_zeros_us,                                  \
+      unsigned: stdc_trailing_zeros_ui,                                        \
+      unsigned long: stdc_trailing_zeros_ul,                                   \
+      unsigned long long: stdc_trailing_zeros_ull)(x)
+#define stdc_trailing_ones(x)                                                 \
+  _Generic((x),                                                                \
+      unsigned char: stdc_trailing_ones_uc,                                   \
+      unsigned short: stdc_trailing_ones_us,                                  \
+      unsigned: stdc_trailing_ones_ui,                                        \
+      unsigned long: stdc_trailing_ones_ul,                                   \
+      unsigned long long: stdc_trailing_ones_ull)(x)
 #endif // __cplusplus
 
 #endif // __LLVM_LIBC_MACROS_STDBIT_MACROS_H
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 6ff2c7c613696..b9fd3bac317b6 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -784,7 +784,17 @@ def StdC : StandardSpec<"stdc"> {
           FunctionSpec<"stdc_leading_ones_us", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedShortType>]>,
           FunctionSpec<"stdc_leading_ones_ui", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedIntType>]>,
           FunctionSpec<"stdc_leading_ones_ul", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongType>]>,
-          FunctionSpec<"stdc_leading_ones_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>
+          FunctionSpec<"stdc_leading_ones_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>,
+          FunctionSpec<"stdc_trailing_zeros_uc", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedCharType>]>,
+          FunctionSpec<"stdc_trailing_zeros_us", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedShortType>]>,
+          FunctionSpec<"stdc_trailing_zeros_ui", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedIntType>]>,
+          FunctionSpec<"stdc_trailing_zeros_ul", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongType>]>,
+          FunctionSpec<"stdc_trailing_zeros_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>,
+          FunctionSpec<"stdc_trailing_ones_uc", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedCharType>]>,
+          FunctionSpec<"stdc_trailing_ones_us", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedShortType>]>,
+          FunctionSpec<"stdc_trailing_ones_ui", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedIntType>]>,
+          FunctionSpec<"stdc_trailing_ones_ul", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongType>]>,
+          FunctionSpec<"stdc_trailing_ones_ull", RetValSpec<UnsignedIntType>, [ArgSpec<UnsignedLongLongType>]>
       ] // Functions
   >;
 
diff --git a/libc/src/stdbit/CMakeLists.txt b/libc/src/stdbit/CMakeLists.txt
index d7daff44dfda6..1904f6f77699f 100644
--- a/libc/src/stdbit/CMakeLists.txt
+++ b/libc/src/stdbit/CMakeLists.txt
@@ -1,99 +1,20 @@
-add_entrypoint_object(
-  stdc_leading_zeros_uc
-  SRCS
-    stdc_leading_zeros_uc.cpp
-  HDRS
-    stdc_leading_zeros_uc.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
-
-add_entrypoint_object(
-  stdc_leading_zeros_us
-  SRCS
-    stdc_leading_zeros_us.cpp
-  HDRS
-    stdc_leading_zeros_us.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
-
-add_entrypoint_object(
-  stdc_leading_zeros_ui
-  SRCS
-    stdc_leading_zeros_ui.cpp
-  HDRS
-    stdc_leading_zeros_ui.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
-
-add_entrypoint_object(
-  stdc_leading_zeros_ul
-  SRCS
-    stdc_leading_zeros_ul.cpp
-  HDRS
-    stdc_leading_zeros_ul.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
-
-add_entrypoint_object(
-  stdc_leading_zeros_ull
-  SRCS
-    stdc_leading_zeros_ull.cpp
-  HDRS
-    stdc_leading_zeros_ull.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
-
-add_entrypoint_object(
-  stdc_leading_ones_uc
-  SRCS
-    stdc_leading_ones_uc.cpp
-  HDRS
-    stdc_leading_ones_uc.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
-
-add_entrypoint_object(
-  stdc_leading_ones_us
-  SRCS
-    stdc_leading_ones_us.cpp
-  HDRS
-    stdc_leading_ones_us.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
-
-add_entrypoint_object(
-  stdc_leading_ones_ui
-  SRCS
-    stdc_leading_ones_ui.cpp
-  HDRS
-    stdc_leading_ones_ui.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
-
-add_entrypoint_object(
-  stdc_leading_ones_ul
-  SRCS
-    stdc_leading_ones_ul.cpp
-  HDRS
-    stdc_leading_ones_ul.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
-
-add_entrypoint_object(
-  stdc_leading_ones_ull
-  SRCS
-    stdc_leading_ones_ull.cpp
-  HDRS
-    stdc_leading_ones_ull.h
-  DEPENDS
-    libc.src.__support.CPP.bit
-)
+list(APPEND prefixes
+  leading_zeros
+  leading_ones
+  trailing_zeros
+  trailing_ones
+)
+list(APPEND suffixes c s i l ll)
+foreach(prefix IN LISTS prefixes)
+  foreach(suffix IN LISTS suffixes)
+    add_entrypoint_object(
+      stdc_${prefix}_u${suffix}
+      SRCS
+        stdc_${prefix}_u${suffix}.cpp
+      HDRS
+        stdc_${prefix}_u${suffix}.h
+      DEPENDS
+        libc.src.__support.CPP.bit
+    )
+  endforeach()
+endforeach()
diff --git a/libc/src/stdbit/stdc_trailing_ones_uc.cpp b/libc/src/stdbit/stdc_trailing_ones_uc.cpp
new file mode 100644
index 0000000000000..eabb21367e285
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_uc.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_trailing_ones_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_trailing_ones_uc.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_ones_uc, (unsigned char value)) {
+  return static_cast<unsigned>(cpp::countr_one(value));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdbit/stdc_trailing_ones_uc.h b/libc/src/stdbit/stdc_trailing_ones_uc.h
new file mode 100644
index 0000000000000..9736e21e1f280
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_uc.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_ones_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_TRAILING_ONES_UC_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_UC_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_ones_uc(unsigned char value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_UC_H
diff --git a/libc/src/stdbit/stdc_trailing_ones_ui.cpp b/libc/src/stdbit/stdc_trailing_ones_ui.cpp
new file mode 100644
index 0000000000000..87eb54fe5f026
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_ui.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_trailing_ones_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_trailing_ones_ui.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_ones_ui, (unsigned value)) {
+  return static_cast<unsigned>(cpp::countr_one(value));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdbit/stdc_trailing_ones_ui.h b/libc/src/stdbit/stdc_trailing_ones_ui.h
new file mode 100644
index 0000000000000..aad7fcf0daf55
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_ui.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_ones_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_TRAILING_ONES_UI_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_UI_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_ones_ui(unsigned value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_UI_H
diff --git a/libc/src/stdbit/stdc_trailing_ones_ul.cpp b/libc/src/stdbit/stdc_trailing_ones_ul.cpp
new file mode 100644
index 0000000000000..6d358a21ac337
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_ul.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_trailing_ones_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_trailing_ones_ul.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_ones_ul, (unsigned long value)) {
+  return static_cast<unsigned>(cpp::countr_one(value));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdbit/stdc_trailing_ones_ul.h b/libc/src/stdbit/stdc_trailing_ones_ul.h
new file mode 100644
index 0000000000000..80589501b1ed2
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_ul.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_ones_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_TRAILING_ONES_UL_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_UL_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_ones_ul(unsigned long value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_UL_H
diff --git a/libc/src/stdbit/stdc_trailing_ones_ull.cpp b/libc/src/stdbit/stdc_trailing_ones_ull.cpp
new file mode 100644
index 0000000000000..883b1f2ff5c07
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_ull.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_trailing_ones_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_trailing_ones_ull.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_ones_ull, (unsigned long long value)) {
+  return static_cast<unsigned>(cpp::countr_one(value));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdbit/stdc_trailing_ones_ull.h b/libc/src/stdbit/stdc_trailing_ones_ull.h
new file mode 100644
index 0000000000000..3d3f0b306789a
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_ull.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_ones_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_TRAILING_ONES_ULL_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_ULL_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_ones_ull(unsigned long long value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_ULL_H
diff --git a/libc/src/stdbit/stdc_trailing_ones_us.cpp b/libc/src/stdbit/stdc_trailing_ones_us.cpp
new file mode 100644
index 0000000000000..ee7ff4f78d489
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_us.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_trailing_ones_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_trailing_ones_us.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_ones_us, (unsigned short value)) {
+  return static_cast<unsigned>(cpp::countr_one(value));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdbit/stdc_trailing_ones_us.h b/libc/src/stdbit/stdc_trailing_ones_us.h
new file mode 100644
index 0000000000000..b783cd22ad2de
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_ones_us.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_ones_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_TRAILING_ONES_US_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_US_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_ones_us(unsigned short value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ONES_US_H
diff --git a/libc/src/stdbit/stdc_trailing_zeros_uc.cpp b/libc/src/stdbit/stdc_trailing_zeros_uc.cpp
new file mode 100644
index 0000000000000..36924c5a053ad
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_zeros_uc.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_trailing_zeros_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_trailing_zeros_uc.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_zeros_uc, (unsigned char value)) {
+  return static_cast<unsigned>(cpp::countr_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdbit/stdc_trailing_zeros_uc.h b/libc/src/stdbit/stdc_trailing_zeros_uc.h
new file mode 100644
index 0000000000000..866201e5acea8
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_zeros_uc.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_zeros_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_TRAILING_ZEROS_UC_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_UC_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_zeros_uc(unsigned char value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_UC_H
diff --git a/libc/src/stdbit/stdc_trailing_zeros_ui.cpp b/libc/src/stdbit/stdc_trailing_zeros_ui.cpp
new file mode 100644
index 0000000000000..a264fd97f251f
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_zeros_ui.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_trailing_zeros_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_trailing_zeros_ui.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_zeros_ui, (unsigned value)) {
+  return static_cast<unsigned>(cpp::countr_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdbit/stdc_trailing_zeros_ui.h b/libc/src/stdbit/stdc_trailing_zeros_ui.h
new file mode 100644
index 0000000000000..0642e312f4fe7
--- /dev/null
+++ b/libc/src/stdbit/stdc_trailing_zeros_ui.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_zeros_ui --------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.o...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/80459


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