string: Use builtins for ffs and ffsll

It allows to remove a lot of arch-specific implementations.

Checked on x86_64, aarch64, powerpc64.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

4 files changed, 2 insertions, 83 deletions

diff --git a/sysdeps/x86_64/ffs.c b/sysdeps/x86_64/ffs.c
deleted file mode 100644
index a049e87b94..0000000000
--- a/sysdeps/x86_64/ffs.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/* ffs -- find first set bit in a word, counted from least significant end.
-   For AMD x86-64.
-   This file is part of the GNU C Library.
-   Copyright (C) 1991-2024 Free Software Foundation, Inc.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#include <string.h>
-
-#undef	ffs
-
-int
-__ffs (int x)
-{
-  int cnt;
-  int tmp;
-
-  asm ("bsfl %2,%0\n"		/* Count low bits in X and store in %1.  */
-       "cmovel %1,%0\n"		/* If number was zero, use -1 as result.  */
-       : "=&r" (cnt), "=r" (tmp) : "rm" (x), "1" (-1));
-
-  return cnt + 1;
-}
-weak_alias (__ffs, ffs)
-libc_hidden_def (__ffs)
-libc_hidden_builtin_def (ffs)
diff --git a/sysdeps/x86_64/ffsll.c b/sysdeps/x86_64/ffsll.c
deleted file mode 100644
index 28444284e6..0000000000
--- a/sysdeps/x86_64/ffsll.c
+++ /dev/null
@@ -1,41 +0,0 @@
-/* ffsll -- find first set bit in a word, counted from least significant end.
-   For AMD x86-64.
-   This file is part of the GNU C Library.
-   Copyright (C) 1991-2024 Free Software Foundation, Inc.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#define ffsl __something_else
-#include <string.h>
-
-#undef	ffsll
-
-int
-ffsll (long long int x)
-{
-  long long int cnt;
-
-  asm ("mov $-1,%k0\n"	/* Initialize cnt to -1.  */
-       "bsf %1,%0\n"	/* Count low bits in x and store in cnt.  */
-       "inc %k0\n"	/* Increment cnt by 1.  */
-       : "=&r" (cnt) : "r" (x));
-
-  return cnt;
-}
-
-#ifndef __ILP32__
-#undef	ffsl
-weak_alias (ffsll, ffsl)
-#endif
diff --git a/sysdeps/x86_64/math-use-builtins-ffs.h b/sysdeps/x86_64/math-use-builtins-ffs.h
new file mode 100644
index 0000000000..a83bb15414
--- /dev/null
+++ b/sysdeps/x86_64/math-use-builtins-ffs.h
@@ -0,0 +1,2 @@
+#define USE_FFS_BUILTIN   1
+#define USE_FFSLL_BUILTIN 1
diff --git a/sysdeps/x86_64/x32/ffs.c b/sysdeps/x86_64/x32/ffs.c
deleted file mode 100644
index fa7de8b887..0000000000
--- a/sysdeps/x86_64/x32/ffs.c
+++ /dev/null
@@ -1,4 +0,0 @@
-#define ffsl __something_else
-#include <sysdeps/x86_64/ffs.c>
-#undef ffsl
-weak_alias (__ffs, ffsl)