[PATCH v2 05/13] x86_64: Remove f{max,min} assembly implementations
Adhemerval Zanella
adhemerval.zanella@linaro.org
Fri Jan 23 13:02:18 GMT 2026
Using recent gcc, the generic implementation generates the same code
for normal and subnormal numbers for float/double.
For long double, the generic implementations generates slight worse
code for the fast-path. With gcc-15:
* sysdeps/x86_64/fpu/s_fmaxl.S
fldt 8(%rsp)
fldt 24(%rsp)
fucomi %st(1), %st
jp 2f
fcmovb %st(1), %st
fstp %st(1)
ret
* generic
fldt 0x8(%rsp)
fldt 0x18(%rsp)
fucomi %st(1),%st
jp 18 <__fmaxl+0x18>
fxch %st(1)
fcomi %st(1),%st
fcmovbe %st(1),%st
fstp %st(1)
ret
It could be optimized by using isgreater instead of a direct comparison
for the non unordered, but this prevents x86 to issue maxsd.
Checked on x86_64-linux-gnu.
---
sysdeps/x86_64/fpu/s_fmax.S | 52 --------------------------------
sysdeps/x86_64/fpu/s_fmaxf.S | 52 --------------------------------
sysdeps/x86_64/fpu/s_fmaxl.S | 58 ------------------------------------
sysdeps/x86_64/fpu/s_fmin.S | 52 --------------------------------
sysdeps/x86_64/fpu/s_fminf.S | 52 --------------------------------
sysdeps/x86_64/fpu/s_fminl.S | 58 ------------------------------------
6 files changed, 324 deletions(-)
delete mode 100644 sysdeps/x86_64/fpu/s_fmax.S
delete mode 100644 sysdeps/x86_64/fpu/s_fmaxf.S
delete mode 100644 sysdeps/x86_64/fpu/s_fmaxl.S
delete mode 100644 sysdeps/x86_64/fpu/s_fmin.S
delete mode 100644 sysdeps/x86_64/fpu/s_fminf.S
delete mode 100644 sysdeps/x86_64/fpu/s_fminl.S
diff --git a/sysdeps/x86_64/fpu/s_fmax.S b/sysdeps/x86_64/fpu/s_fmax.S
deleted file mode 100644
index e86701c86a..0000000000
--- a/sysdeps/x86_64/fpu/s_fmax.S
+++ /dev/null
@@ -1,52 +0,0 @@
-/* Compute maximum of two numbers, regarding NaN as missing argument.
- Copyright (C) 2002-2026 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>
-#include <libm-alias-double.h>
-
- .text
-ENTRY(__fmax)
- ucomisd %xmm0, %xmm1
- jp 1f // jump if unordered
- maxsd %xmm1, %xmm0
- jmp 2f
-
-1: ucomisd %xmm1, %xmm1 // Is xmm1 a NaN?
- jp 3f
- // xmm0 is a NaN; xmm1 is not. Test if xmm0 is signaling.
- movsd %xmm0, -8(%rsp)
- testb $0x8, -2(%rsp)
- jz 4f
- movsd %xmm1, %xmm0 // otherwise return xmm1
- ret
-
-3: // xmm1 is a NaN; xmm0 may or may not be.
- ucomisd %xmm0, %xmm0
- jp 4f
- // xmm1 is a NaN; xmm0 is not. Test if xmm1 is signaling.
- movsd %xmm1, -8(%rsp)
- testb $0x8, -2(%rsp)
- jz 4f
- ret
-
-4: // Both arguments are NaNs, or one is a signaling NaN.
- addsd %xmm1, %xmm0
-
-2: ret
-END(__fmax)
-libm_alias_double (__fmax, fmax)
diff --git a/sysdeps/x86_64/fpu/s_fmaxf.S b/sysdeps/x86_64/fpu/s_fmaxf.S
deleted file mode 100644
index ebb61a922e..0000000000
--- a/sysdeps/x86_64/fpu/s_fmaxf.S
+++ /dev/null
@@ -1,52 +0,0 @@
-/* Compute maximum of two numbers, regarding NaN as missing argument.
- Copyright (C) 2002-2026 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>
-#include <libm-alias-float.h>
-
- .text
-ENTRY(__fmaxf)
- ucomiss %xmm0, %xmm1
- jp 1f // jump if unordered
- maxss %xmm1, %xmm0
- jmp 2f
-
-1: ucomiss %xmm1, %xmm1 // Is xmm1 a NaN?
- jp 3f
- // xmm0 is a NaN; xmm1 is not. Test if xmm0 is signaling.
- movss %xmm0, -4(%rsp)
- testb $0x40, -2(%rsp)
- jz 4f
- movss %xmm1, %xmm0 // otherwise return xmm1
- ret
-
-3: // xmm1 is a NaN; xmm0 may or may not be.
- ucomiss %xmm0, %xmm0
- jp 4f
- // xmm1 is a NaN; xmm0 is not. Test if xmm1 is signaling.
- movss %xmm1, -4(%rsp)
- testb $0x40, -2(%rsp)
- jz 4f
- ret
-
-4: // Both arguments are NaNs, or one is a signaling NaN.
- addss %xmm1, %xmm0
-
-2: ret
-END(__fmaxf)
-libm_alias_float (__fmax, fmax)
diff --git a/sysdeps/x86_64/fpu/s_fmaxl.S b/sysdeps/x86_64/fpu/s_fmaxl.S
deleted file mode 100644
index 2bba9d24c1..0000000000
--- a/sysdeps/x86_64/fpu/s_fmaxl.S
+++ /dev/null
@@ -1,58 +0,0 @@
-/* Compute maximum of two numbers, regarding NaN as missing argument.
- Copyright (C) 1997-2026 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>
-#include <libm-alias-ldouble.h>
-
- .text
-ENTRY(__fmaxl)
- fldt 8(%rsp) // x
- fldt 24(%rsp) // x : y
-
- fucomi %st(1), %st
- jp 2f
- fcmovb %st(1), %st
-
- fstp %st(1)
-
- ret
-
-2: // Unordered.
- fucomi %st(0), %st
- jp 3f
- // st(1) is a NaN; st(0) is not. Test if st(1) is signaling.
- testb $0x40, 15(%rsp)
- jz 4f
- fstp %st(1)
- ret
-
-3: // st(0) is a NaN; st(1) may or may not be.
- fxch
- fucomi %st(0), %st
- jp 4f
- // st(1) is a NaN; st(0) is not. Test if st(1) is signaling.
- testb $0x40, 31(%rsp)
- jz 4f
- fstp %st(1)
- ret
-
-4: // Both arguments are NaNs, or one is a signaling NaN.
- faddp
- ret
-END(__fmaxl)
-libm_alias_ldouble (__fmax, fmax)
diff --git a/sysdeps/x86_64/fpu/s_fmin.S b/sysdeps/x86_64/fpu/s_fmin.S
deleted file mode 100644
index 27409767cc..0000000000
--- a/sysdeps/x86_64/fpu/s_fmin.S
+++ /dev/null
@@ -1,52 +0,0 @@
-/* Compute minimum of two numbers, regarding NaN as missing argument.
- Copyright (C) 2002-2026 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>
-#include <libm-alias-double.h>
-
- .text
-ENTRY(__fmin)
- ucomisd %xmm0, %xmm1
- jp 1f // jump if unordered
- minsd %xmm1, %xmm0
- jmp 2f
-
-1: ucomisd %xmm1, %xmm1 // Is xmm1 a NaN?
- jp 3f
- // xmm0 is a NaN; xmm1 is not. Test if xmm0 is signaling.
- movsd %xmm0, -8(%rsp)
- testb $0x8, -2(%rsp)
- jz 4f
- movsd %xmm1, %xmm0 // otherwise return xmm1
- ret
-
-3: // xmm1 is a NaN; xmm0 may or may not be.
- ucomisd %xmm0, %xmm0
- jp 4f
- // xmm1 is a NaN; xmm0 is not. Test if xmm1 is signaling.
- movsd %xmm1, -8(%rsp)
- testb $0x8, -2(%rsp)
- jz 4f
- ret
-
-4: // Both arguments are NaNs, or one is a signaling NaN.
- addsd %xmm1, %xmm0
-
-2: ret
-END(__fmin)
-libm_alias_double (__fmin, fmin)
diff --git a/sysdeps/x86_64/fpu/s_fminf.S b/sysdeps/x86_64/fpu/s_fminf.S
deleted file mode 100644
index f0c58b78a0..0000000000
--- a/sysdeps/x86_64/fpu/s_fminf.S
+++ /dev/null
@@ -1,52 +0,0 @@
-/* Compute minimum of two numbers, regarding NaN as missing argument.
- Copyright (C) 2002-2026 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>
-#include <libm-alias-float.h>
-
- .text
-ENTRY(__fminf)
- ucomiss %xmm0, %xmm1
- jp 1f // jump if unordered
- minss %xmm1, %xmm0
- jmp 2f
-
-1: ucomiss %xmm1, %xmm1 // Is xmm1 a NaN?
- jp 3f
- // xmm0 is a NaN; xmm1 is not. Test if xmm0 is signaling.
- movss %xmm0, -4(%rsp)
- testb $0x40, -2(%rsp)
- jz 4f
- movss %xmm1, %xmm0 // otherwise return xmm1
- ret
-
-3: // xmm1 is a NaN; xmm0 may or may not be.
- ucomiss %xmm0, %xmm0
- jp 4f
- // xmm1 is a NaN; xmm0 is not. Test if xmm1 is signaling.
- movss %xmm1, -4(%rsp)
- testb $0x40, -2(%rsp)
- jz 4f
- ret
-
-4: // Both arguments are NaNs, or one is a signaling NaN.
- addss %xmm1, %xmm0
-
-2: ret
-END(__fminf)
-libm_alias_float (__fmin, fmin)
diff --git a/sysdeps/x86_64/fpu/s_fminl.S b/sysdeps/x86_64/fpu/s_fminl.S
deleted file mode 100644
index 4712417f39..0000000000
--- a/sysdeps/x86_64/fpu/s_fminl.S
+++ /dev/null
@@ -1,58 +0,0 @@
-/* Compute minimum of two numbers, regarding NaN as missing argument.
- Copyright (C) 1997-2026 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>
-#include <libm-alias-ldouble.h>
-
- .text
-ENTRY(__fminl)
- fldt 8(%rsp) // x
- fldt 24(%rsp) // x : y
-
- fucomi %st(1), %st
- jp 2f
- fcmovnb %st(1), %st
-
- fstp %st(1)
-
- ret
-
-2: // Unordered.
- fucomi %st(0), %st
- jp 3f
- // st(1) is a NaN; st(0) is not. Test if st(1) is signaling.
- testb $0x40, 15(%rsp)
- jz 4f
- fstp %st(1)
- ret
-
-3: // st(0) is a NaN; st(1) may or may not be.
- fxch
- fucomi %st(0), %st
- jp 4f
- // st(1) is a NaN; st(0) is not. Test if st(1) is signaling.
- testb $0x40, 31(%rsp)
- jz 4f
- fstp %st(1)
- ret
-
-4: // Both arguments are NaNs, or one is a signaling NaN.
- faddp
- ret
-END(__fminl)
-libm_alias_ldouble (__fmin, fmin)
--
2.43.0
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