[PATCH v4 01/21] i386: Remove the SVID error handling from fmod

[Adhemerval Zanella]

The optimized i386 version is faster than the generic one, and gcc
implements it through the builtin. It allows us to move the
implementation to a C one. The performance on a Zen3 chip is
similar to the SVID one.

Tested on i686-linux-gnu.
---
 sysdeps/i386/fpu/Versions                 |  4 +++
 sysdeps/i386/fpu/e_fmod.S                 | 18 ----------
 sysdeps/i386/fpu/e_fmod.c                 | 41 +++++++++++++++++++++++
 sysdeps/i386/fpu/w_fmod_compat.c          | 15 ---------
 sysdeps/mach/hurd/i386/libm.abilist       |  1 +
 sysdeps/unix/sysv/linux/i386/libm.abilist |  1 +
 6 files changed, 47 insertions(+), 33 deletions(-)
 delete mode 100644 sysdeps/i386/fpu/e_fmod.S
 create mode 100644 sysdeps/i386/fpu/e_fmod.c
 delete mode 100644 sysdeps/i386/fpu/w_fmod_compat.c

diff --git a/sysdeps/i386/fpu/Versions b/sysdeps/i386/fpu/Versions
index a2eec371f16..940384a21f4 100644
--- a/sysdeps/i386/fpu/Versions
+++ b/sysdeps/i386/fpu/Versions
@@ -3,4 +3,8 @@ libm {
     # functions used in inline functions or macros
     __expl; __expm1l;
   }
+  GLIBC_2.43 {
+    # No SVID compatible error handling.
+    fmod;
+  }
 }
diff --git a/sysdeps/i386/fpu/e_fmod.S b/sysdeps/i386/fpu/e_fmod.S
deleted file mode 100644
index 86ac1bcfafa..00000000000
--- a/sysdeps/i386/fpu/e_fmod.S
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * Public domain.
- */
-
-#include <machine/asm.h>
-#include <libm-alias-finite.h>
-
-ENTRY(__ieee754_fmod)
-	fldl	12(%esp)
-	fldl	4(%esp)
-1:	fprem
-	fstsw	%ax
-	sahf
-	jp	1b
-	fstp	%st(1)
-	ret
-END (__ieee754_fmod)
-libm_alias_finite (__ieee754_fmod, __fmod)
diff --git a/sysdeps/i386/fpu/e_fmod.c b/sysdeps/i386/fpu/e_fmod.c
new file mode 100644
index 00000000000..281b23dffc0
--- /dev/null
+++ b/sysdeps/i386/fpu/e_fmod.c
@@ -0,0 +1,41 @@
+/* Floating-point remainder function.
+   Copyright (C) 2023-2025 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 <libm-alias-double.h>
+#include <libm-alias-finite.h>
+#include <math.h>
+#include "math_config.h"
+
+double
+__fmod (double x, double y)
+{
+  uint64_t hx = asuint64 (x);
+  uint64_t hy = asuint64 (y);
+
+  /* fmod(+-Inf,y) or fmod(x,0) */
+  if (__glibc_unlikely ((is_inf (hx) || y == 0.0)
+			&& !is_nan (hy)
+			&& !is_nan (hx)))
+    return __math_invalid (x);
+
+  return __builtin_fmod (x, y);
+}
+strong_alias (__fmod, __ieee754_fmod)
+libm_alias_finite (__ieee754_fmod, __fmod)
+versioned_symbol (libm, __fmod, fmod, GLIBC_2_43);
+libm_alias_double_other (__fmod, fmod)
diff --git a/sysdeps/i386/fpu/w_fmod_compat.c b/sysdeps/i386/fpu/w_fmod_compat.c
deleted file mode 100644
index 528bfc2a135..00000000000
--- a/sysdeps/i386/fpu/w_fmod_compat.c
+++ /dev/null
@@ -1,15 +0,0 @@
-/* i386 provides an optimized __ieee752_fmod.  */
-#include <math-svid-compat.h>
-#ifdef SHARED
-# undef SHLIB_COMPAT
-# define SHLIB_COMPAT(a, b, c) 1
-# undef LIBM_SVID_COMPAT
-# define LIBM_SVID_COMPAT 1
-# undef compat_symbol
-# define compat_symbol(a, b, c, d)
-# include <math/w_fmod_compat.c>
-libm_alias_double (__fmod_compat, fmod)
-#else
-#include <math-type-macros-double.h>
-#include <w_fmod_template.c>
-#endif
diff --git a/sysdeps/mach/hurd/i386/libm.abilist b/sysdeps/mach/hurd/i386/libm.abilist
index 47d215fae2f..6c8e2b6d9cb 100644
--- a/sysdeps/mach/hurd/i386/libm.abilist
+++ b/sysdeps/mach/hurd/i386/libm.abilist
@@ -1317,3 +1317,4 @@ GLIBC_2.42 rsqrtf32x F
 GLIBC_2.42 rsqrtf64 F
 GLIBC_2.42 rsqrtf64x F
 GLIBC_2.42 rsqrtl F
+GLIBC_2.43 fmod F
diff --git a/sysdeps/unix/sysv/linux/i386/libm.abilist b/sysdeps/unix/sysv/linux/i386/libm.abilist
index de77b0f0713..5f545098126 100644
--- a/sysdeps/unix/sysv/linux/i386/libm.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libm.abilist
@@ -1324,3 +1324,4 @@ GLIBC_2.42 rsqrtf32x F
 GLIBC_2.42 rsqrtf64 F
 GLIBC_2.42 rsqrtf64x F
 GLIBC_2.42 rsqrtl F
+GLIBC_2.43 fmod F
-- 
2.43.0