string: Use builtins for ffs and ffsll

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

Checked on x86_64, aarch64, powerpc64.
---
 string/ffs.c                            |  6 +-
 string/ffsll.c                          | 10 ++-
 sysdeps/aarch64/math-use-builtins-ffs.h |  2 +
 sysdeps/alpha/alphaev67/ffs.S           | 51 --------------
 sysdeps/alpha/alphaev67/ffsll.S         | 44 ------------
 sysdeps/alpha/ffs.S                     | 90 -------------------------
 sysdeps/alpha/ffsll.S                   |  1 -
 sysdeps/alpha/math-use-builtins-ffs.h   |  7 ++
 sysdeps/arc/math-use-builtins-ffs.h     |  2 +
 sysdeps/arm/armv6t2/ffs.S               | 36 ----------
 sysdeps/arm/armv6t2/ffsll.S             | 50 --------------
 sysdeps/arm/math-use-builtins-ffs.h     |  2 +
 sysdeps/generic/math-use-builtins-ffs.h |  2 +
 sysdeps/generic/math-use-builtins.h     |  1 +
 sysdeps/i386/ffs.c                      | 49 --------------
 sysdeps/i386/i686/ffs.c                 | 47 -------------
 sysdeps/i386/math-use-builtins-ffs.h    |  2 +
 sysdeps/ia64/math-use-builtins-ffs.h    |  2 +
 sysdeps/m68k/ffs.c                      | 46 -------------
 sysdeps/powerpc/ffs.c                   | 46 -------------
 sysdeps/powerpc/math-use-builtins-ffs.h |  6 ++
 sysdeps/powerpc/powerpc64/ffsll.c       | 36 ----------
 sysdeps/s390/ffs.c                      | 69 -------------------
 sysdeps/x86_64/ffs.c                    | 38 -----------
 sysdeps/x86_64/ffsll.c                  | 41 -----------
 sysdeps/x86_64/math-use-builtins-ffs.h  |  2 +
 sysdeps/x86_64/x32/ffs.c                |  4 --
 27 files changed, 41 insertions(+), 651 deletions(-)
 create mode 100644 sysdeps/aarch64/math-use-builtins-ffs.h
 delete mode 100644 sysdeps/alpha/alphaev67/ffs.S
 delete mode 100644 sysdeps/alpha/alphaev67/ffsll.S
 delete mode 100644 sysdeps/alpha/ffs.S
 delete mode 100644 sysdeps/alpha/ffsll.S
 create mode 100644 sysdeps/alpha/math-use-builtins-ffs.h
 create mode 100644 sysdeps/arc/math-use-builtins-ffs.h
 delete mode 100644 sysdeps/arm/armv6t2/ffs.S
 delete mode 100644 sysdeps/arm/armv6t2/ffsll.S
 create mode 100644 sysdeps/arm/math-use-builtins-ffs.h
 create mode 100644 sysdeps/generic/math-use-builtins-ffs.h
 delete mode 100644 sysdeps/i386/ffs.c
 delete mode 100644 sysdeps/i386/i686/ffs.c
 create mode 100644 sysdeps/i386/math-use-builtins-ffs.h
 create mode 100644 sysdeps/ia64/math-use-builtins-ffs.h
 delete mode 100644 sysdeps/m68k/ffs.c
 delete mode 100644 sysdeps/powerpc/ffs.c
 create mode 100644 sysdeps/powerpc/math-use-builtins-ffs.h
 delete mode 100644 sysdeps/powerpc/powerpc64/ffsll.c
 delete mode 100644 sysdeps/s390/ffs.c
 delete mode 100644 sysdeps/x86_64/ffs.c
 delete mode 100644 sysdeps/x86_64/ffsll.c
 create mode 100644 sysdeps/x86_64/math-use-builtins-ffs.h
 delete mode 100644 sysdeps/x86_64/x32/ffs.c
  

Ping.

On 17/07/23 11:34, Adhemerval Zanella wrote:
> It allows to remove a lot of arch-specific implementations.
> 
> Checked on x86_64, aarch64, powerpc64.
> ---
>  string/ffs.c                            |  6 +-
>  string/ffsll.c                          | 10 ++-
>  sysdeps/aarch64/math-use-builtins-ffs.h |  2 +
>  sysdeps/alpha/alphaev67/ffs.S           | 51 --------------
>  sysdeps/alpha/alphaev67/ffsll.S         | 44 ------------
>  sysdeps/alpha/ffs.S                     | 90 -------------------------
>  sysdeps/alpha/ffsll.S                   |  1 -
>  sysdeps/alpha/math-use-builtins-ffs.h   |  7 ++
>  sysdeps/arc/math-use-builtins-ffs.h     |  2 +
>  sysdeps/arm/armv6t2/ffs.S               | 36 ----------
>  sysdeps/arm/armv6t2/ffsll.S             | 50 --------------
>  sysdeps/arm/math-use-builtins-ffs.h     |  2 +
>  sysdeps/generic/math-use-builtins-ffs.h |  2 +
>  sysdeps/generic/math-use-builtins.h     |  1 +
>  sysdeps/i386/ffs.c                      | 49 --------------
>  sysdeps/i386/i686/ffs.c                 | 47 -------------
>  sysdeps/i386/math-use-builtins-ffs.h    |  2 +
>  sysdeps/ia64/math-use-builtins-ffs.h    |  2 +
>  sysdeps/m68k/ffs.c                      | 46 -------------
>  sysdeps/powerpc/ffs.c                   | 46 -------------
>  sysdeps/powerpc/math-use-builtins-ffs.h |  6 ++
>  sysdeps/powerpc/powerpc64/ffsll.c       | 36 ----------
>  sysdeps/s390/ffs.c                      | 69 -------------------
>  sysdeps/x86_64/ffs.c                    | 38 -----------
>  sysdeps/x86_64/ffsll.c                  | 41 -----------
>  sysdeps/x86_64/math-use-builtins-ffs.h  |  2 +
>  sysdeps/x86_64/x32/ffs.c                |  4 --
>  27 files changed, 41 insertions(+), 651 deletions(-)
>  create mode 100644 sysdeps/aarch64/math-use-builtins-ffs.h
>  delete mode 100644 sysdeps/alpha/alphaev67/ffs.S
>  delete mode 100644 sysdeps/alpha/alphaev67/ffsll.S
>  delete mode 100644 sysdeps/alpha/ffs.S
>  delete mode 100644 sysdeps/alpha/ffsll.S
>  create mode 100644 sysdeps/alpha/math-use-builtins-ffs.h
>  create mode 100644 sysdeps/arc/math-use-builtins-ffs.h
>  delete mode 100644 sysdeps/arm/armv6t2/ffs.S
>  delete mode 100644 sysdeps/arm/armv6t2/ffsll.S
>  create mode 100644 sysdeps/arm/math-use-builtins-ffs.h
>  create mode 100644 sysdeps/generic/math-use-builtins-ffs.h
>  delete mode 100644 sysdeps/i386/ffs.c
>  delete mode 100644 sysdeps/i386/i686/ffs.c
>  create mode 100644 sysdeps/i386/math-use-builtins-ffs.h
>  create mode 100644 sysdeps/ia64/math-use-builtins-ffs.h
>  delete mode 100644 sysdeps/m68k/ffs.c
>  delete mode 100644 sysdeps/powerpc/ffs.c
>  create mode 100644 sysdeps/powerpc/math-use-builtins-ffs.h
>  delete mode 100644 sysdeps/powerpc/powerpc64/ffsll.c
>  delete mode 100644 sysdeps/s390/ffs.c
>  delete mode 100644 sysdeps/x86_64/ffs.c
>  delete mode 100644 sysdeps/x86_64/ffsll.c
>  create mode 100644 sysdeps/x86_64/math-use-builtins-ffs.h
>  delete mode 100644 sysdeps/x86_64/x32/ffs.c
> 
> diff --git a/string/ffs.c b/string/ffs.c
> index bf58f0b7ca..8302ae8420 100644
> --- a/string/ffs.c
> +++ b/string/ffs.c
> @@ -18,13 +18,16 @@
>  #include <limits.h>
>  #define ffsl __something_else
>  #include <string.h>
> -
>  #undef	ffs
> +#include <math-use-builtins.h>
>  
>  /* Find the first bit set in I.  */
>  int
>  __ffs (int i)
>  {
> +#if USE_FFS_BUILTIN
> +  return __builtin_ffs (i);
> +#else
>    static const unsigned char table[] =
>      {
>        0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
> @@ -42,6 +45,7 @@ __ffs (int i)
>    a = x <= 0xffff ? (x <= 0xff ? 0 : 8) : (x <= 0xffffff ?  16 : 24);
>  
>    return table[x >> a] + a;
> +#endif
>  }
>  weak_alias (__ffs, ffs)
>  libc_hidden_def (__ffs)
> diff --git a/string/ffsll.c b/string/ffsll.c
> index 0cc461a1cf..2315fe1bd7 100644
> --- a/string/ffsll.c
> +++ b/string/ffsll.c
> @@ -18,20 +18,26 @@
>  #include <limits.h>
>  #define ffsl __something_else
>  #include <string.h>
> -
>  #undef	ffsll
> +#include <math-use-builtins.h>
> +#include <libc-diag.h>
>  
>  /* Find the first bit set in I.  */
>  int
> -ffsll (long long int i)
> +__ffsll (long long int i)
>  {
> +#if USE_FFSLL_BUILTIN
> +  return __builtin_ffsll (i);
> +#else
>    unsigned long long int x = i & -i;
>  
>    if (x <= 0xffffffff)
>      return ffs (i);
>    else
>      return 32 + ffs (i >> 32);
> +#endif
>  }
> +weak_alias (__ffsll, ffsll)
>  
>  #if ULONG_MAX != UINT_MAX
>  #undef ffsl
> diff --git a/sysdeps/aarch64/math-use-builtins-ffs.h b/sysdeps/aarch64/math-use-builtins-ffs.h
> new file mode 100644
> index 0000000000..a83bb15414
> --- /dev/null
> +++ b/sysdeps/aarch64/math-use-builtins-ffs.h
> @@ -0,0 +1,2 @@
> +#define USE_FFS_BUILTIN   1
> +#define USE_FFSLL_BUILTIN 1
> diff --git a/sysdeps/alpha/alphaev67/ffs.S b/sysdeps/alpha/alphaev67/ffs.S
> deleted file mode 100644
> index 48361bd8c5..0000000000
> --- a/sysdeps/alpha/alphaev67/ffs.S
> +++ /dev/null
> @@ -1,51 +0,0 @@
> -/* Copyright (C) 2000-2023 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   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/>.  */
> -
> -/* Finds the first bit set in an integer.  */
> -
> -#include <sysdep.h>
> -
> -	.arch ev6
> -	.set noreorder
> -	.set noat
> -
> -
> -ENTRY(__ffs)
> -#ifdef PROF
> -	ldgp	gp, 0(pv)
> -	lda	AT, _mcount
> -	jsr	AT, (AT), _mcount
> -	.prologue 1
> -#else
> -	.prologue 0
> -#endif
> -
> -	zap	$16, 0xF0, $16
> -	cttz	$16, $0
> -	addq	$0, 1, $0
> -	cmoveq	$16, 0, $0
> -
> -	nop
> -	nop
> -	nop
> -	ret
> -
> -END(__ffs)
> -
> -weak_alias (__ffs, ffs)
> -libc_hidden_def (__ffs)
> -libc_hidden_builtin_def (ffs)
> diff --git a/sysdeps/alpha/alphaev67/ffsll.S b/sysdeps/alpha/alphaev67/ffsll.S
> deleted file mode 100644
> index 52f406ec32..0000000000
> --- a/sysdeps/alpha/alphaev67/ffsll.S
> +++ /dev/null
> @@ -1,44 +0,0 @@
> -/* Copyright (C) 2000-2023 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   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/>.  */
> -
> -/* Finds the first bit set in a long.  */
> -
> -#include <sysdep.h>
> -
> -	.arch ev6
> -	.set noreorder
> -	.set noat
> -
> -ENTRY(ffsl)
> -#ifdef PROF
> -	ldgp	gp, 0(pv)
> -	lda	AT, _mcount
> -	jsr	AT, (AT), _mcount
> -	.prologue 1
> -#else
> -	.prologue 0
> -#endif
> -
> -	cttz	$16, $0
> -	addq	$0, 1, $0
> -	cmoveq	$16, 0, $0
> -	ret
> -
> -END(ffsl)
> -
> -weak_extern (ffsl)
> -weak_alias (ffsl, ffsll)
> diff --git a/sysdeps/alpha/ffs.S b/sysdeps/alpha/ffs.S
> deleted file mode 100644
> index 047fd60352..0000000000
> --- a/sysdeps/alpha/ffs.S
> +++ /dev/null
> @@ -1,90 +0,0 @@
> -/* Copyright (C) 1996-2023 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   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/>.  */
> -
> -/* Finds the first bit set in an integer.  Optimized for the Alpha
> -   architecture.  */
> -
> -#include <sysdep.h>
> -
> -	.set noreorder
> -	.set noat
> -
> -
> -ENTRY(__ffs)
> -#ifdef PROF
> -	ldgp	gp, 0(pv)
> -	lda	AT, _mcount
> -	jsr	AT, (AT), _mcount
> -	.prologue 1
> -	zap	$16, 0xF0, $16
> -	br	$ffsl..ng
> -#else
> -	.prologue 0
> -	zap	$16, 0xF0, $16
> -	# FALLTHRU
> -#endif
> -END(__ffs)
> -
> -	.align 4
> -ENTRY(ffsl)
> -#ifdef PROF
> -	ldgp	gp, 0(pv)
> -	lda	AT, _mcount
> -	jsr	AT, (AT), _mcount
> -	.prologue 1
> -$ffsl..ng:
> -#else
> -	.prologue 0
> -#endif
> -	not	$16, $1		# e0    :
> -	ldi	$2, -1		# .. e1 :
> -	cmpbge	$1, $2, $3	# e0    : bit N == 1 for byte N == 0
> -	clr	$0		# .. e1 :
> -	addq	$3, 1, $4	# e0    :
> -	bic	$4, $3, $3	# e1    : bit N == 1 for first byte N != 0
> -	and	$3, 0xF0, $4	# e0    :
> -	and	$3, 0xCC, $5	# .. e1 :
> -	and	$3, 0xAA, $6	# e0    :
> -	cmovne	$4, 4, $0	# .. e1 :
> -	cmovne	$5, 2, $5	# e0    :
> -	cmovne  $6, 1, $6	# .. e1 :
> -	addl	$0, $5, $0	# e0    :
> -	addl	$0, $6, $0	# e1    : $0 == N
> -	extbl	$16, $0, $1	# e0    : $1 == byte N
> -	ldi	$2, 1		# .. e1 :
> -	negq	$1, $3		# e0    :
> -	and	$3, $1, $3	# e1    : bit N == least bit set of byte N
> -	and	$3, 0xF0, $4	# e0    :
> -	and	$3, 0xCC, $5	# .. e1 :
> -	and	$3, 0xAA, $6	# e0    :
> -	cmovne	$4, 5, $2	# .. e1 :
> -	cmovne	$5, 2, $5	# e0    :
> -	cmovne	$6, 1, $6	# .. e1 :
> -	s8addl	$0, $2, $0	# e0    : mult byte ofs by 8 and sum
> -	addl	$5, $6, $5	# .. e1 :
> -	addl	$0, $5, $0	# e0    :
> -	nop			# .. e1 :
> -	cmoveq	$16, 0, $0	# e0    : trap input == 0 case.
> -	ret			# .. e1 : 18
> -
> -END(ffsl)
> -
> -weak_alias (__ffs, ffs)
> -libc_hidden_def (__ffs)
> -libc_hidden_builtin_def (ffs)
> -weak_extern (ffsl)
> -weak_alias (ffsl, ffsll)
> diff --git a/sysdeps/alpha/ffsll.S b/sysdeps/alpha/ffsll.S
> deleted file mode 100644
> index b2f46d899c..0000000000
> --- a/sysdeps/alpha/ffsll.S
> +++ /dev/null
> @@ -1 +0,0 @@
> -/* This function is defined in ffs.S.  */
> diff --git a/sysdeps/alpha/math-use-builtins-ffs.h b/sysdeps/alpha/math-use-builtins-ffs.h
> new file mode 100644
> index 0000000000..9925e374ac
> --- /dev/null
> +++ b/sysdeps/alpha/math-use-builtins-ffs.h
> @@ -0,0 +1,7 @@
> +#ifdef __alpha_cix__
> +# define USE_FFS_BUILTIN   1
> +# define USE_FFSLL_BUILTIN 1
> +#else
> +# define USE_FFS_BUILTIN   0
> +# define USE_FFSLL_BUILTIN 0
> +#endif
> diff --git a/sysdeps/arc/math-use-builtins-ffs.h b/sysdeps/arc/math-use-builtins-ffs.h
> new file mode 100644
> index 0000000000..c0f108c264
> --- /dev/null
> +++ b/sysdeps/arc/math-use-builtins-ffs.h
> @@ -0,0 +1,2 @@
> +#define USE_FFS_BUILTIN   1
> +#define USE_FFSLL_BUILTIN 0
> diff --git a/sysdeps/arm/armv6t2/ffs.S b/sysdeps/arm/armv6t2/ffs.S
> deleted file mode 100644
> index 870957a4bb..0000000000
> --- a/sysdeps/arm/armv6t2/ffs.S
> +++ /dev/null
> @@ -1,36 +0,0 @@
> -/* ffs -- find first set bit in an int, from least significant end.
> -   Copyright (C) 2013-2023 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   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 <sysdep.h>
> -
> -	.syntax unified
> -	.text
> -
> -ENTRY (__ffs)
> -	cmp	r0, #0
> -	rbit	r0, r0
> -	itt	ne
> -	clzne	r0, r0
> -	addne	r0, r0, #1
> -	bx	lr
> -END (__ffs)
> -
> -weak_alias (__ffs, ffs)
> -weak_alias (__ffs, ffsl)
> -libc_hidden_def (__ffs)
> -libc_hidden_builtin_def (ffs)
> diff --git a/sysdeps/arm/armv6t2/ffsll.S b/sysdeps/arm/armv6t2/ffsll.S
> deleted file mode 100644
> index bc3cbf81b0..0000000000
> --- a/sysdeps/arm/armv6t2/ffsll.S
> +++ /dev/null
> @@ -1,50 +0,0 @@
> -/* ffsll -- find first set bit in a long long, from least significant end.
> -   Copyright (C) 2013-2023 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   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 <sysdep.h>
> -
> -	.syntax unified
> -	.text
> -
> -ENTRY (ffsll)
> -	@ If low part is 0, operate on the high part.  Ensure that the
> -	@ word on which we operate is in r0.  Set r2 to the bit offset
> -	@ of the word being considered.  Set the flags for the word
> -	@ being operated on.
> -#ifdef __ARMEL__
> -	cmp	r0, #0
> -	itee	ne
> -	movne	r2, #0
> -	moveq	r2, #32
> -	movseq	r0, r1
> -#else
> -	cmp	r1, #0
> -	ittee	ne
> -	movne	r2, #0
> -	movne	r0, r1
> -	moveq	r2, #32
> -	cmpeq	r0, #0
> -#endif
> -	@ Perform the ffs on r0.
> -	rbit	r0, r0
> -	ittt	ne
> -	clzne	r0, r0
> -	addne	r2, r2, #1
> -	addne	r0, r0, r2
> -	bx	lr
> -END (ffsll)
> diff --git a/sysdeps/arm/math-use-builtins-ffs.h b/sysdeps/arm/math-use-builtins-ffs.h
> new file mode 100644
> index 0000000000..c0f108c264
> --- /dev/null
> +++ b/sysdeps/arm/math-use-builtins-ffs.h
> @@ -0,0 +1,2 @@
> +#define USE_FFS_BUILTIN   1
> +#define USE_FFSLL_BUILTIN 0
> diff --git a/sysdeps/generic/math-use-builtins-ffs.h b/sysdeps/generic/math-use-builtins-ffs.h
> new file mode 100644
> index 0000000000..add8537470
> --- /dev/null
> +++ b/sysdeps/generic/math-use-builtins-ffs.h
> @@ -0,0 +1,2 @@
> +#define USE_FFS_BUILTIN   0
> +#define USE_FFSLL_BUILTIN 0
> diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
> index 04b1d0d5ab..038eb2c523 100644
> --- a/sysdeps/generic/math-use-builtins.h
> +++ b/sysdeps/generic/math-use-builtins.h
> @@ -40,5 +40,6 @@
>  #include <math-use-builtins-lrint.h>
>  #include <math-use-builtins-llrint.h>
>  #include <math-use-builtins-logb.h>
> +#include <math-use-builtins-ffs.h>
>  
>  #endif /* MATH_USE_BUILTINS_H  */
> diff --git a/sysdeps/i386/ffs.c b/sysdeps/i386/ffs.c
> deleted file mode 100644
> index b8e798420b..0000000000
> --- a/sysdeps/i386/ffs.c
> +++ /dev/null
> @@ -1,49 +0,0 @@
> -/* ffs -- find first set bit in a word, counted from least significant end.
> -   For Intel 80x86, x>=3.
> -   This file is part of the GNU C Library.
> -   Copyright (C) 1991-2023 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	ffs
> -
> -#ifdef	__GNUC__
> -
> -int
> -__ffs (int x)
> -{
> -  int cnt;
> -  int tmp;
> -
> -  asm ("xorl %0,%0\n"		/* Set CNT to zero.  */
> -       "bsfl %2,%1\n"		/* Count low bits in X and store in %1.  */
> -       "jz 1f\n"		/* Jump if OK, i.e. X was non-zero.  */
> -       "leal 1(%1),%0\n"	/* Return bsfl-result plus one on %0.  */
> -       "1:" : "=&a" (cnt), "=r" (tmp) : "rm" (x));
> -
> -  return cnt;
> -}
> -weak_alias (__ffs, ffs)
> -libc_hidden_def (__ffs)
> -libc_hidden_builtin_def (ffs)
> -#undef ffsl
> -weak_alias (__ffs, ffsl)
> -
> -#else
> -#include <string/ffs.c>
> -#endif
> diff --git a/sysdeps/i386/i686/ffs.c b/sysdeps/i386/i686/ffs.c
> deleted file mode 100644
> index a522077cfe..0000000000
> --- a/sysdeps/i386/i686/ffs.c
> +++ /dev/null
> @@ -1,47 +0,0 @@
> -/* ffs -- find first set bit in a word, counted from least significant end.
> -   For Intel 80x86, x>=6.
> -   This file is part of the GNU C Library.
> -   Copyright (C) 1991-2023 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	ffs
> -
> -#ifdef	__GNUC__
> -
> -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)
> -#undef ffsl
> -weak_alias (__ffs, ffsl)
> -
> -#else
> -#include <string/ffs.c>
> -#endif
> diff --git a/sysdeps/i386/math-use-builtins-ffs.h b/sysdeps/i386/math-use-builtins-ffs.h
> new file mode 100644
> index 0000000000..c0f108c264
> --- /dev/null
> +++ b/sysdeps/i386/math-use-builtins-ffs.h
> @@ -0,0 +1,2 @@
> +#define USE_FFS_BUILTIN   1
> +#define USE_FFSLL_BUILTIN 0
> diff --git a/sysdeps/ia64/math-use-builtins-ffs.h b/sysdeps/ia64/math-use-builtins-ffs.h
> new file mode 100644
> index 0000000000..a83bb15414
> --- /dev/null
> +++ b/sysdeps/ia64/math-use-builtins-ffs.h
> @@ -0,0 +1,2 @@
> +#define USE_FFS_BUILTIN   1
> +#define USE_FFSLL_BUILTIN 1
> diff --git a/sysdeps/m68k/ffs.c b/sysdeps/m68k/ffs.c
> deleted file mode 100644
> index 4415bb0cff..0000000000
> --- a/sysdeps/m68k/ffs.c
> +++ /dev/null
> @@ -1,46 +0,0 @@
> -/* ffs -- find first set bit in a word, counted from least significant end.
> -   For mc68020, mc68030, mc68040.
> -   This file is part of the GNU C Library.
> -   Copyright (C) 1991-2023 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	ffs
> -
> -#if	defined (__GNUC__) && defined (__mc68020__)
> -
> -int
> -__ffs (int x)
> -{
> -  int cnt;
> -
> -  asm ("bfffo %1{#0:#0},%0" : "=d" (cnt) : "dm" (x & -x));
> -
> -  return 32 - cnt;
> -}
> -weak_alias (__ffs, ffs)
> -libc_hidden_def (__ffs)
> -libc_hidden_builtin_def (ffs)
> -#undef ffsl
> -weak_alias (__ffs, ffsl)
> -
> -#else
> -
> -#include <string/ffs.c>
> -
> -#endif
> diff --git a/sysdeps/powerpc/ffs.c b/sysdeps/powerpc/ffs.c
> deleted file mode 100644
> index 0a046dab99..0000000000
> --- a/sysdeps/powerpc/ffs.c
> +++ /dev/null
> @@ -1,46 +0,0 @@
> -/* Find first set bit in a word, counted from least significant end.
> -   For PowerPC.
> -   Copyright (C) 1991-2023 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   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 <limits.h>
> -#include <string.h>
> -
> -#undef	ffs
> -
> -#ifdef 	__GNUC__
> -
> -int
> -__ffs (int x)
> -{
> -  int cnt;
> -
> -  asm ("cntlzw %0,%1" : "=r" (cnt) : "r" (x & -x));
> -  return 32 - cnt;
> -}
> -weak_alias (__ffs, ffs)
> -libc_hidden_def (__ffs)
> -libc_hidden_builtin_def (ffs)
> -#if ULONG_MAX == UINT_MAX
> -#undef ffsl
> -weak_alias (__ffs, ffsl)
> -#endif
> -
> -#else
> -#include <string/ffs.c>
> -#endif
> diff --git a/sysdeps/powerpc/math-use-builtins-ffs.h b/sysdeps/powerpc/math-use-builtins-ffs.h
> new file mode 100644
> index 0000000000..7b1d401823
> --- /dev/null
> +++ b/sysdeps/powerpc/math-use-builtins-ffs.h
> @@ -0,0 +1,6 @@
> +#define USE_FFS_BUILTIN    1
> +#ifdef __powerpc64__
> +# define USE_FFSLL_BUILTIN 1
> +#else
> +# define USE_FFSLL_BUILTIN 0
> +#endif
> diff --git a/sysdeps/powerpc/powerpc64/ffsll.c b/sysdeps/powerpc/powerpc64/ffsll.c
> deleted file mode 100644
> index d17cdd1c6b..0000000000
> --- a/sysdeps/powerpc/powerpc64/ffsll.c
> +++ /dev/null
> @@ -1,36 +0,0 @@
> -/* Find first set bit in a word, counted from least significant end.
> -   For PowerPC.
> -   Copyright (C) 1991-2023 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   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 <limits.h>
> -#include <string.h>
> -
> -#undef	ffs
> -
> -int
> -__ffsll (long long int x)
> -{
> -  int cnt;
> -
> -  asm ("cntlzd %0,%1" : "=r" (cnt) : "r" (x & -x));
> -  return 64 - cnt;
> -}
> -weak_alias (__ffsll, ffsll)
> -#undef ffsl
> -weak_alias (__ffsll, ffsl)
> diff --git a/sysdeps/s390/ffs.c b/sysdeps/s390/ffs.c
> deleted file mode 100644
> index 7627bd3346..0000000000
> --- a/sysdeps/s390/ffs.c
> +++ /dev/null
> @@ -1,69 +0,0 @@
> -/* ffs -- find first set bit in a word, counted from least significant end.
> -   S/390 version.
> -   Copyright (C) 2000-2023 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   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 <limits.h>
> -#define ffsl __something_else
> -#include <string.h>
> -
> -#undef	ffs
> -
> -/* ffs: find first bit set. This is defined the same way as
> -   the libc and compiler builtin ffs routines, therefore
> -   differs in spirit from the above ffz (man ffs).  */
> -
> -int
> -__ffs (int x)
> -{
> -	int r;
> -
> -	if (x == 0)
> -	  return 0;
> -	__asm__("    lr	  %%r1,%1\n"
> -		"    sr	  %0,%0\n"
> -		"    tml  %%r1,0xFFFF\n"
> -		"    jnz  0f\n"
> -		"    ahi  %0,16\n"
> -		"    srl  %%r1,16\n"
> -		"0:  tml  %%r1,0x00FF\n"
> -		"    jnz  1f\n"
> -		"    ahi  %0,8\n"
> -		"    srl  %%r1,8\n"
> -		"1:  tml  %%r1,0x000F\n"
> -		"    jnz  2f\n"
> -		"    ahi  %0,4\n"
> -		"    srl  %%r1,4\n"
> -		"2:  tml  %%r1,0x0003\n"
> -		"    jnz  3f\n"
> -		"    ahi  %0,2\n"
> -		"    srl  %%r1,2\n"
> -		"3:  tml  %%r1,0x0001\n"
> -		"    jnz  4f\n"
> -		"    ahi  %0,1\n"
> -		"4:"
> -		: "=&d" (r) : "d" (x) : "cc", "1" );
> -	return r+1;
> -}
> -
> -weak_alias (__ffs, ffs)
> -libc_hidden_def (__ffs)
> -libc_hidden_builtin_def (ffs)
> -#if ULONG_MAX == UINT_MAX
> -#undef ffsl
> -weak_alias (__ffs, ffsl)
> -#endif
> diff --git a/sysdeps/x86_64/ffs.c b/sysdeps/x86_64/ffs.c
> deleted file mode 100644
> index a31202969e..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) 1991-2023 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 a1c13d4906..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) 1991-2023 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;
> -  long long int tmp;
> -
> -  asm ("bsfq %2,%0\n"		/* Count low bits in X and store in %1.  */
> -       "cmoveq %1,%0\n"		/* If number was zero, use -1 as result.  */
> -       : "=&r" (cnt), "=r" (tmp) : "rm" (x), "1" (-1));
> -
> -  return cnt + 1;
> -}
> -
> -#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)
  

Please add

diff --git c/sysdeps/m68k/math-use-builtins-ffs.h i/sysdeps/m68k/math-use-builtins-ffs.h
new file mode 100644
index 0000000000..4e1d994453
--- /dev/null
+++ i/sysdeps/m68k/math-use-builtins-ffs.h
@@ -0,0 +1,7 @@
+#if defined __mc68020__ || defined __mc68030__ || defined __mc68040__ \
+    || defined __mc68060__
+# define USE_FFS_BUILTIN  1
+#else
+# define USE_FFS_BUILTIN  0
+#endif
+#define USE_FFSLL_BUILTIN 0