[libc][stdbit] implement stdc_trailing_zeros (C23) (llvm#80344)

libc/config/linux/x86_64/entrypoints.txt

@@ -102,6 +102,11 @@ 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
 
     # stdlib.h entrypoints
     libc.src.stdlib.abs

libc/include/llvm-libc-macros/stdbit-macros.h

@@ -40,6 +40,21 @@ 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);
+}
 #else
 #define stdc_leading_zeros(x)                                                  \
   _Generic((x),                                                                \
@@ -55,6 +70,13 @@ 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)
 #endif // __cplusplus
 
 #endif // __LLVM_LIBC_MACROS_STDBIT_MACROS_H

libc/spec/stdc.td

@@ -775,7 +775,9 @@ def StdC : StandardSpec<"stdc"> {
   HeaderSpec StdBit = HeaderSpec<
       "stdbit.h",
       [
-        Macro<"stdc_leading_zeros">
+        Macro<"stdc_leading_zeros">,
+        Macro<"stdc_leading_ones">,
+        Macro<"stdc_trailing_zeros">
       ], // Macros
       [], // Types
       [], // Enumerations
@@ -789,7 +791,12 @@ 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>]>
       ] // Functions
   >;
 

libc/src/stdbit/CMakeLists.txt

@@ -1,99 +1,19 @@
-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
-)
+set(prefixes
+  leading_zeros
+  leading_ones
+  trailing_zeros
+)
+set(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()

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

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

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

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.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_UI_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_UI_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_zeros_ui(unsigned value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_UI_H

libc/src/stdbit/stdc_trailing_zeros_ul.cpp

@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_trailing_zeros_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_zeros_ul.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_zeros_ul, (unsigned long value)) {
+  return static_cast<unsigned>(cpp::countr_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/stdbit/stdc_trailing_zeros_ul.h

@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_zeros_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_ZEROS_UL_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_UL_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_zeros_ul(unsigned long value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_UL_H

libc/src/stdbit/stdc_trailing_zeros_ull.cpp

@@ -0,0 +1,21 @@
+//===-- Implementation of stdc_trailing_zeros_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_zeros_ull.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_zeros_ull,
+                   (unsigned long long value)) {
+  return static_cast<unsigned>(cpp::countr_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/stdbit/stdc_trailing_zeros_ull.h

@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_zeros_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_ZEROS_ULL_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_ULL_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_zeros_ull(unsigned long long value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_ULL_H

libc/src/stdbit/stdc_trailing_zeros_us.cpp

@@ -0,0 +1,20 @@
+//===-- Implementation of stdc_trailing_zeros_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_zeros_us.h"
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(unsigned, stdc_trailing_zeros_us, (unsigned short value)) {
+  return static_cast<unsigned>(cpp::countr_zero(value));
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/stdbit/stdc_trailing_zeros_us.h

@@ -0,0 +1,18 @@
+//===-- Implementation header for stdc_trailing_zeros_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_ZEROS_US_H
+#define LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_US_H
+
+namespace LIBC_NAMESPACE {
+
+unsigned stdc_trailing_zeros_us(unsigned short value);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDBIT_STDC_TRAILING_ZEROS_US_H