From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Wed, 8 Oct 2025 13:55:02 +0000 (-0300)
Subject: i386: Remove the SVID error handling from fmodf
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1dd2163e51c84ec78b3f6425d3266808a5570de4;p=thirdparty%2Fglibc.git

i386: Remove the SVID error handling from fmodf

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 slight better:

reciprocal-throughput           input   master  no-SVID  improvement
i686                       subnormals  22.4741  20.1571       10.31%
i686                           normal  74.1631  70.3606        5.13%
i686                   close-exponent  22.5625  20.2435       10.28%

Tested on i686-linux-gnu.

Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>
---

diff --git a/sysdeps/i386/fpu/Versions b/sysdeps/i386/fpu/Versions
index 940384a21f4..8668b42dd6a 100644
--- a/sysdeps/i386/fpu/Versions
+++ b/sysdeps/i386/fpu/Versions
@@ -5,6 +5,6 @@ libm {
   }
   GLIBC_2.43 {
     # No SVID compatible error handling.
-    fmod;
+    fmod; fmodf;
   }
 }
diff --git a/sysdeps/i386/fpu/e_fmodf.S b/sysdeps/i386/fpu/e_fmodf.S
deleted file mode 100644
index f73ce9da1ef..00000000000
--- a/sysdeps/i386/fpu/e_fmodf.S
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * Public domain.
- */
-
-#include <machine/asm.h>
-#include <libm-alias-finite.h>
-
-ENTRY(__ieee754_fmodf)
-	flds	8(%esp)
-	flds	4(%esp)
-1:	fprem
-	fstsw	%ax
-	sahf
-	jp	1b
-	fstp	%st(1)
-	ret
-END(__ieee754_fmodf)
-libm_alias_finite (__ieee754_fmodf, __fmodf)
diff --git a/sysdeps/i386/fpu/e_fmodf.c b/sysdeps/i386/fpu/e_fmodf.c
new file mode 100644
index 00000000000..5b05d0fd958
--- /dev/null
+++ b/sysdeps/i386/fpu/e_fmodf.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-finite.h>
+#include <libm-alias-float.h>
+#include <math.h>
+#include "sysdeps/ieee754/flt-32/math_config.h"
+
+float
+__fmodf (float x, float y)
+{
+  uint32_t hx = asuint (x);
+  uint32_t hy = asuint (y);
+
+  /* fmod(+-Inf,y) or fmod(x,0) */
+  if (__glibc_unlikely ((is_inf (hx) || y == 0.0f)
+			&& !is_nan (hy)
+			&& !is_nan (hx)))
+    return __math_invalidf (x);
+
+  return __builtin_fmodf (x, y);
+}
+strong_alias (__fmodf, __ieee754_fmodf)
+versioned_symbol (libm, __fmodf, fmodf, GLIBC_2_43);
+libm_alias_float_other (__fmod, fmod)
+libm_alias_finite (__ieee754_fmodf, __fmodf)
diff --git a/sysdeps/i386/fpu/e_fmodf_ver.h b/sysdeps/i386/fpu/e_fmodf_ver.h
new file mode 100644
index 00000000000..384d7917d24
--- /dev/null
+++ b/sysdeps/i386/fpu/e_fmodf_ver.h
@@ -0,0 +1,2 @@
+/* i386 remove SVID wrapper on 2.43 */
+#define FMODF_NOSVID_VER   GLIBC_2_43
diff --git a/sysdeps/i386/fpu/w_fmodf_compat.c b/sysdeps/i386/fpu/w_fmodf_compat.c
deleted file mode 100644
index 5a61693e51f..00000000000
--- a/sysdeps/i386/fpu/w_fmodf_compat.c
+++ /dev/null
@@ -1,15 +0,0 @@
-/* i386 provides an optimized __ieee752_fmodf.  */
-#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_fmodf_compat.c>
-libm_alias_float (__fmod_compat, fmod)
-#else
-#include <math-type-macros-float.h>
-#include <w_fmod_template.c>
-#endif
diff --git a/sysdeps/mach/hurd/i386/libm.abilist b/sysdeps/mach/hurd/i386/libm.abilist
index 6c8e2b6d9cb..3bf087812ca 100644
--- a/sysdeps/mach/hurd/i386/libm.abilist
+++ b/sysdeps/mach/hurd/i386/libm.abilist
@@ -1318,3 +1318,4 @@ GLIBC_2.42 rsqrtf64 F
 GLIBC_2.42 rsqrtf64x F
 GLIBC_2.42 rsqrtl F
 GLIBC_2.43 fmod F
+GLIBC_2.43 fmodf F
diff --git a/sysdeps/unix/sysv/linux/i386/libm.abilist b/sysdeps/unix/sysv/linux/i386/libm.abilist
index 5f545098126..38e31ed1a76 100644
--- a/sysdeps/unix/sysv/linux/i386/libm.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libm.abilist
@@ -1325,3 +1325,4 @@ GLIBC_2.42 rsqrtf64 F
 GLIBC_2.42 rsqrtf64x F
 GLIBC_2.42 rsqrtl F
 GLIBC_2.43 fmod F
+GLIBC_2.43 fmodf F