[PATCH v3] string: Use builtins for ffs and ffsll

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

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

Checked on x86_64, aarch64, powerpc64.
--
Changes from v2:
* Fix arm math-use-builtins-ffs.h placement.
---
 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/armv6t2/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/m68k/math-use-builtins-ffs.h        |  7 ++
 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 -
 28 files changed, 48 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/armv6t2/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
 create mode 100644 sysdeps/m68k/math-use-builtins-ffs.h
 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/armv6t2/math-use-builtins-ffs.h b/sysdeps/arm/armv6t2/math-use-builtins-ffs.h
new file mode 100644
index 0000000000..c0f108c264
--- /dev/null
+++ b/sysdeps/arm/armv6t2/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/m68k/math-use-builtins-ffs.h b/sysdeps/m68k/math-use-builtins-ffs.h
new file mode 100644
index 0000000000..4e1d994453
--- /dev/null
+++ b/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
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)
-- 
2.34.1