[PATCH v6 1/3] math: redirect roundeven function

[PATCH v6 1/3] math: redirect roundeven function

[Shen-Ta Hsieh]

This patch redirect roundeven function for futhermore changes.

Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
---
 include/math.h                             | 2 +-
 sysdeps/ieee754/dbl-64/s_roundeven.c       | 4 +++-
 sysdeps/ieee754/float128/s_roundevenf128.c | 1 +
 sysdeps/ieee754/flt-32/s_roundevenf.c      | 3 +++
 sysdeps/ieee754/ldbl-128/s_roundevenl.c    | 1 +
 sysdeps/ieee754/ldbl-96/s_roundevenl.c     | 1 +
 6 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/math.h b/include/math.h
index e1c2a4eb64..b4772d3d3b 100644
--- a/include/math.h
+++ b/include/math.h
@@ -38,7 +38,6 @@ libm_hidden_proto (__issignaling)
 libm_hidden_proto (__issignalingf)
 libm_hidden_proto (__exp)
 libm_hidden_proto (__expf)
-libm_hidden_proto (__roundeven)
 
 #  if !defined __NO_LONG_DOUBLE_MATH \
       && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0
@@ -159,6 +158,7 @@ fabsf128 (_Float128 x)
 MATH_REDIRECT (sqrt, "__ieee754_", MATH_REDIRECT_UNARY_ARGS)
 MATH_REDIRECT (ceil, "__", MATH_REDIRECT_UNARY_ARGS)
 MATH_REDIRECT (floor, "__", MATH_REDIRECT_UNARY_ARGS)
+MATH_REDIRECT (roundeven, "__", MATH_REDIRECT_UNARY_ARGS)
 MATH_REDIRECT (rint, "__", MATH_REDIRECT_UNARY_ARGS)
 MATH_REDIRECT (trunc, "__", MATH_REDIRECT_UNARY_ARGS)
 MATH_REDIRECT (round, "__", MATH_REDIRECT_UNARY_ARGS)
diff --git a/sysdeps/ieee754/dbl-64/s_roundeven.c b/sysdeps/ieee754/dbl-64/s_roundeven.c
index 943b2c634c..5deff3bb8a 100644
--- a/sysdeps/ieee754/dbl-64/s_roundeven.c
+++ b/sysdeps/ieee754/dbl-64/s_roundeven.c
@@ -16,6 +16,7 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#define NO_MATH_REDIRECT
 #include <math.h>
 #include <math_private.h>
 #include <libm-alias-double.h>
@@ -66,5 +67,6 @@ __roundeven (double x)
   INSERT_WORDS64 (x, ix);
   return x;
 }
-hidden_def (__roundeven)
+#ifndef __roundeven
 libm_alias_double (__roundeven, roundeven)
+#endif
diff --git a/sysdeps/ieee754/float128/s_roundevenf128.c b/sysdeps/ieee754/float128/s_roundevenf128.c
index 5a9b3f395f..e0faf727f6 100644
--- a/sysdeps/ieee754/float128/s_roundevenf128.c
+++ b/sysdeps/ieee754/float128/s_roundevenf128.c
@@ -1,2 +1,3 @@
+#define NO_MATH_REDIRECT
 #include <float128_private.h>
 #include "../ldbl-128/s_roundevenl.c"
diff --git a/sysdeps/ieee754/flt-32/s_roundevenf.c b/sysdeps/ieee754/flt-32/s_roundevenf.c
index ae54365bbe..2cc0d7b001 100644
--- a/sysdeps/ieee754/flt-32/s_roundevenf.c
+++ b/sysdeps/ieee754/flt-32/s_roundevenf.c
@@ -17,6 +17,7 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#define NO_MATH_REDIRECT
 #include <math.h>
 #include <math_private.h>
 #include <libm-alias-float.h>
@@ -67,4 +68,6 @@ __roundevenf (float x)
   SET_FLOAT_WORD (x, ix);
   return x;
 }
+#ifndef __roundevenf
 libm_alias_float (__roundeven, roundeven)
+#endif
diff --git a/sysdeps/ieee754/ldbl-128/s_roundevenl.c b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
index 02765be0e0..7c9c11fad2 100644
--- a/sysdeps/ieee754/ldbl-128/s_roundevenl.c
+++ b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
@@ -17,6 +17,7 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#define NO_MATH_REDIRECT
 #include <math.h>
 #include <math_private.h>
 #include <libm-alias-ldouble.h>
diff --git a/sysdeps/ieee754/ldbl-96/s_roundevenl.c b/sysdeps/ieee754/ldbl-96/s_roundevenl.c
index 8340116ed8..f826829c31 100644
--- a/sysdeps/ieee754/ldbl-96/s_roundevenl.c
+++ b/sysdeps/ieee754/ldbl-96/s_roundevenl.c
@@ -17,6 +17,7 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#define NO_MATH_REDIRECT
 #include <math.h>
 #include <math_private.h>
 #include <libm-alias-ldouble.h>
-- 
2.31.1

[PATCH v6 2/3] x86_64: roundeven with sse4.1 support

[Shen-Ta Hsieh]

This patch adds support for the sse4.1 hardware floating point
roundeven.

Here is a benchmark result on my AMD Ryzen 9 3900X system:

* benchmark result before this commit
|            |    roundeven |   roundevenf |
|------------|--------------|--------------|
| duration   |  3.77659e+09 |  3.77504e+09 |
| iterations |  3.97043e+08 |  4.36752e+08 |
| max        | 83.714       | 58.861       |
| min        |  7.144       |  6.27        |
| mean       |  9.51179     |  8.64345     |

* benchmark result after this commit
|            |    roundeven |   roundevenf |
|------------|--------------|--------------|
| duration   |  3.76913e+09 |  3.76923e+09 |
| iterations |  5.55921e+08 |  5.64822e+08 |
| max        | 211.698      | 439.09       |
| min        |  6.498       |  6.422       |
| mean       |  6.77998     |  6.6733      |

Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
---
 sysdeps/x86_64/fpu/multiarch/Makefile         |  5 +--
 sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c  |  2 ++
 .../x86_64/fpu/multiarch/s_roundeven-sse4_1.S | 24 ++++++++++++++
 sysdeps/x86_64/fpu/multiarch/s_roundeven.c    | 31 +++++++++++++++++++
 sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c |  3 ++
 .../fpu/multiarch/s_roundevenf-sse4_1.S       | 24 ++++++++++++++
 sysdeps/x86_64/fpu/multiarch/s_roundevenf.c   | 31 +++++++++++++++++++
 7 files changed, 118 insertions(+), 2 deletions(-)
 create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c
 create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S
 create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundeven.c
 create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c
 create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S
 create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundevenf.c

diff --git a/sysdeps/x86_64/fpu/multiarch/Makefile b/sysdeps/x86_64/fpu/multiarch/Makefile
index 57892c56bb..d425ffd6d3 100644
--- a/sysdeps/x86_64/fpu/multiarch/Makefile
+++ b/sysdeps/x86_64/fpu/multiarch/Makefile
@@ -1,11 +1,12 @@
 ifeq ($(subdir),math)
 libm-sysdep_routines += s_floor-c s_ceil-c s_floorf-c s_ceilf-c \
 			s_rint-c s_rintf-c s_nearbyint-c s_nearbyintf-c \
-			s_trunc-c s_truncf-c
+			s_roundeven-c s_roundevenf-c s_trunc-c s_truncf-c
 
 libm-sysdep_routines += s_ceil-sse4_1 s_ceilf-sse4_1 s_floor-sse4_1 \
 			s_floorf-sse4_1 s_nearbyint-sse4_1 \
-			s_nearbyintf-sse4_1 s_rint-sse4_1 s_rintf-sse4_1 \
+			s_nearbyintf-sse4_1 s_roundeven-sse4_1 \
+			s_roundevenf-sse4_1 s_rint-sse4_1 s_rintf-sse4_1 \
 			s_trunc-sse4_1 s_truncf-sse4_1
 
 libm-sysdep_routines += e_exp-fma e_log-fma e_pow-fma s_atan-fma \
diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c b/sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c
new file mode 100644
index 0000000000..c7be43cb22
--- /dev/null
+++ b/sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c
@@ -0,0 +1,2 @@
+#define __roundeven __roundeven_c
+#include <sysdeps/ieee754/dbl-64/s_roundeven.c>
diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S b/sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S
new file mode 100644
index 0000000000..6ae8f6b1d3
--- /dev/null
+++ b/sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S
@@ -0,0 +1,24 @@
+/* Copyright (C) 2021 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>
+
+	.section .text.sse4.1,"ax",@progbits
+ENTRY(__roundeven_sse41)
+	roundsd	$8, %xmm0, %xmm0
+	ret
+END(__roundeven_sse41)
diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundeven.c b/sysdeps/x86_64/fpu/multiarch/s_roundeven.c
new file mode 100644
index 0000000000..d92eda652a
--- /dev/null
+++ b/sysdeps/x86_64/fpu/multiarch/s_roundeven.c
@@ -0,0 +1,31 @@
+/* Multiple versions of __roundeven.
+   Copyright (C) 2021 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>
+
+#define roundeven __redirect_roundeven
+#define __roundeven __redirect___roundeven
+#include <math.h>
+#undef roundeven
+#undef __roundeven
+
+#define SYMBOL_NAME roundeven
+#include "ifunc-sse4_1.h"
+
+libc_ifunc_redirected (__redirect_roundeven, __roundeven, IFUNC_SELECTOR ());
+libm_alias_double (__roundeven, roundeven)
diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c
new file mode 100644
index 0000000000..72a6e7d1fb
--- /dev/null
+++ b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c
@@ -0,0 +1,3 @@
+#undef __roundevenf
+#define __roundevenf __roundevenf_c
+#include <sysdeps/ieee754/flt-32/s_roundevenf.c>
diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S
new file mode 100644
index 0000000000..a76e10807e
--- /dev/null
+++ b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S
@@ -0,0 +1,24 @@
+/* Copyright (C) 2021 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>
+
+	.section .text.sse4.1,"ax",@progbits
+ENTRY(__roundevenf_sse41)
+	roundss	$8, %xmm0, %xmm0
+	ret
+END(__roundevenf_sse41)
diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundevenf.c b/sysdeps/x86_64/fpu/multiarch/s_roundevenf.c
new file mode 100644
index 0000000000..2ee196e68f
--- /dev/null
+++ b/sysdeps/x86_64/fpu/multiarch/s_roundevenf.c
@@ -0,0 +1,31 @@
+/* Multiple versions of __roundevenf.
+   Copyright (C) 2021 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-float.h>
+
+#define roundevenf __redirect_roundevenf
+#define __roundevenf __redirect___roundevenf
+#include <math.h>
+#undef roundevenf
+#undef __roundevenf
+
+#define SYMBOL_NAME roundevenf
+#include "ifunc-sse4_1.h"
+
+libc_ifunc_redirected (__redirect_roundevenf, __roundevenf, IFUNC_SELECTOR ());
+libm_alias_float (__roundeven, roundeven)
-- 
2.31.1

[PATCH v6 3/3] Use GCC builtins for roundeven functions if desired.

[Shen-Ta Hsieh]

This patch is using the corresponding GCC builtin for roundevenf,
roundeven and roundevenl if the USE_FUNCTION_BUILTIN macros are defined
to one in math-use-builtins.h.

These builtin functions is supported since GCC 10.

The code of the generic implementation is not changed.

Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
---
 sysdeps/generic/math-use-builtins-roundeven.h | 4 ++++
 sysdeps/generic/math-use-builtins.h           | 1 +
 sysdeps/ieee754/dbl-64/s_roundeven.c          | 5 +++++
 sysdeps/ieee754/flt-32/s_roundevenf.c         | 5 +++++
 sysdeps/ieee754/ldbl-128/s_roundevenl.c       | 5 +++++
 5 files changed, 20 insertions(+)
 create mode 100644 sysdeps/generic/math-use-builtins-roundeven.h

diff --git a/sysdeps/generic/math-use-builtins-roundeven.h b/sysdeps/generic/math-use-builtins-roundeven.h
new file mode 100644
index 0000000000..bd2e84c93f
--- /dev/null
+++ b/sysdeps/generic/math-use-builtins-roundeven.h
@@ -0,0 +1,4 @@
+#define USE_ROUNDEVEN_BUILTIN 0
+#define USE_ROUNDEVENF_BUILTIN 0
+#define USE_ROUNDEVENL_BUILTIN 0
+#define USE_ROUNDEVENF128_BUILTIN 0
diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
index cc3e9f2201..19d2d1cf3c 100644
--- a/sysdeps/generic/math-use-builtins.h
+++ b/sysdeps/generic/math-use-builtins.h
@@ -30,6 +30,7 @@
 #include <math-use-builtins-ceil.h>
 #include <math-use-builtins-trunc.h>
 #include <math-use-builtins-round.h>
+#include <math-use-builtins-roundeven.h>
 #include <math-use-builtins-copysign.h>
 #include <math-use-builtins-sqrt.h>
 #include <math-use-builtins-fma.h>
diff --git a/sysdeps/ieee754/dbl-64/s_roundeven.c b/sysdeps/ieee754/dbl-64/s_roundeven.c
index 5deff3bb8a..88c051e9fe 100644
--- a/sysdeps/ieee754/dbl-64/s_roundeven.c
+++ b/sysdeps/ieee754/dbl-64/s_roundeven.c
@@ -21,6 +21,7 @@
 #include <math_private.h>
 #include <libm-alias-double.h>
 #include <stdint.h>
+#include <math-use-builtins.h>
 
 #define BIAS 0x3ff
 #define MANT_DIG 53
@@ -29,6 +30,9 @@
 double
 __roundeven (double x)
 {
+#if USE_ROUNDEVEN_BUILTIN
+  return __builtin_roundeven (x);
+#else
   uint64_t ix, ux;
   EXTRACT_WORDS64 (ix, x);
   ux = ix & 0x7fffffffffffffffULL;
@@ -66,6 +70,7 @@ __roundeven (double x)
     ix &= 0x8000000000000000ULL;
   INSERT_WORDS64 (x, ix);
   return x;
+#endif /* ! USE_ROUNDEVEN_BUILTIN  */
 }
 #ifndef __roundeven
 libm_alias_double (__roundeven, roundeven)
diff --git a/sysdeps/ieee754/flt-32/s_roundevenf.c b/sysdeps/ieee754/flt-32/s_roundevenf.c
index 2cc0d7b001..4f568579d8 100644
--- a/sysdeps/ieee754/flt-32/s_roundevenf.c
+++ b/sysdeps/ieee754/flt-32/s_roundevenf.c
@@ -21,6 +21,7 @@
 #include <math.h>
 #include <math_private.h>
 #include <libm-alias-float.h>
+#include <math-use-builtins.h>
 #include <stdint.h>
 
 #define BIAS 0x7f
@@ -30,6 +31,9 @@
 float
 __roundevenf (float x)
 {
+#if USE_ROUNDEVENF_BUILTIN
+  return __builtin_roundevenf (x);
+#else
   uint32_t ix, ux;
   GET_FLOAT_WORD (ix, x);
   ux = ix & 0x7fffffff;
@@ -67,6 +71,7 @@ __roundevenf (float x)
     ix &= 0x80000000;
   SET_FLOAT_WORD (x, ix);
   return x;
+#endif /* ! USE_ROUNDEVENF_BUILTIN  */
 }
 #ifndef __roundevenf
 libm_alias_float (__roundeven, roundeven)
diff --git a/sysdeps/ieee754/ldbl-128/s_roundevenl.c b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
index 7c9c11fad2..afbf13d4f2 100644
--- a/sysdeps/ieee754/ldbl-128/s_roundevenl.c
+++ b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
@@ -21,6 +21,7 @@
 #include <math.h>
 #include <math_private.h>
 #include <libm-alias-ldouble.h>
+#include <math-use-builtins.h>
 #include <stdint.h>
 
 #define BIAS 0x3fff
@@ -30,6 +31,9 @@
 _Float128
 __roundevenl (_Float128 x)
 {
+#if USE_ROUNDEVENL_BUILTIN
+  return __builtin_roundevenl (x);
+#else
   uint64_t hx, lx, uhx;
   GET_LDOUBLE_WORDS64 (hx, lx, x);
   uhx = hx & 0x7fffffffffffffffULL;
@@ -101,5 +105,6 @@ __roundevenl (_Float128 x)
     }
   SET_LDOUBLE_WORDS64 (x, hx, lx);
   return x;
+#endif /* ! USE_ROUNDEVENL_BUILTIN  */
 }
 libm_alias_ldouble (__roundeven, roundeven)
-- 
2.31.1

Re: [PATCH v6 2/3] x86_64: roundeven with sse4.1 support

[Paul Zimmermann]

       Dear Shen-Ta,

> Here is a benchmark result on my AMD Ryzen 9 3900X system:
> 
> * benchmark result before this commit
> |            |    roundeven |   roundevenf |
> |------------|--------------|--------------|
> | duration   |  3.77659e+09 |  3.77504e+09 |
> | iterations |  3.97043e+08 |  4.36752e+08 |
> | max        | 83.714       | 58.861       |
> | min        |  7.144       |  6.27        |
> | mean       |  9.51179     |  8.64345     |
> 
> * benchmark result after this commit
> |            |    roundeven |   roundevenf |
> |------------|--------------|--------------|
> | duration   |  3.76913e+09 |  3.76923e+09 |
> | iterations |  5.55921e+08 |  5.64822e+08 |
> | max        | 211.698      | 439.09       |
> | min        |  6.498       |  6.422       |
> | mean       |  6.77998     |  6.6733      |

I wonder why the max times have increased by a factor 2.5 and 7.5.
In my experiments I noticed that the "mean" time was quite stable,
while the "max" time could vary a lot between different runs. Thus
I usually run 5 times "make bench" and keep the smallest times:

$ ./testrun.sh benchtests/bench-roundeven

You can also try make USE_RDTSCP=1 bench (cf benchtests/README).

And it would be nice to have figures on another hardware (for example Intel).

Best regards,
Paul Zimmermann

Re: [PATCH v6 2/3] x86_64: roundeven with sse4.1 support

[謝昇達(Shen-Ta Hsieh)]

Dear Paul,

Paul Zimmermann <Paul.Zimmermann@inria.fr> 於 2021年5月22日 週六 下午12:52寫道：
>
>        Dear Shen-Ta,
>
> > Here is a benchmark result on my AMD Ryzen 9 3900X system:
> >
> > * benchmark result before this commit
> > |            |    roundeven |   roundevenf |
> > |------------|--------------|--------------|
> > | duration   |  3.77659e+09 |  3.77504e+09 |
> > | iterations |  3.97043e+08 |  4.36752e+08 |
> > | max        | 83.714       | 58.861       |
> > | min        |  7.144       |  6.27        |
> > | mean       |  9.51179     |  8.64345     |
> >
> > * benchmark result after this commit
> > |            |    roundeven |   roundevenf |
> > |------------|--------------|--------------|
> > | duration   |  3.76913e+09 |  3.76923e+09 |
> > | iterations |  5.55921e+08 |  5.64822e+08 |
> > | max        | 211.698      | 439.09       |
> > | min        |  6.498       |  6.422       |
> > | mean       |  6.77998     |  6.6733      |
>
> I wonder why the max times have increased by a factor 2.5 and 7.5.
> In my experiments I noticed that the "mean" time was quite stable,
> while the "max" time could vary a lot between different runs. Thus
> I usually run 5 times "make bench" and keep the smallest times:
>
> $ ./testrun.sh benchtests/bench-roundeven
>
> You can also try make USE_RDTSCP=1 bench (cf benchtests/README).
>
> And it would be nice to have figures on another hardware (for example Intel).
>
> Best regards,
> Paul Zimmermann
>

I've tried to run another benchmark following your advises, and here
is the result:

# AMD Ryzen 9 3900X 12-Core Processor

* benchmark result before this commit
|            |    roundeven |   roundevenf |
|------------|--------------|--------------|
| duration   |  3.75587e+09 |  3.75114e+09 |
| iterations |  3.93053e+08 |  4.35402e+08 |
| max        | 52.592       | 58.71        |
| min        |  7.98        |  7.22        |
| mean       |  9.55563     |  8.61535     |

* benchmark result after this commit
|            |     roundeven |   roundevenf |
|------------|---------------|--------------|
| duration   |   3.73815e+09 |  3.73738e+09 |
| iterations |   5.82692e+08 |  5.91498e+08 |
| max        |  56.468       | 51.642       |
| min        |   6.27        |  6.156       |
| mean       |   6.41532     |  6.3185      |

# Intel(R) Pentium(R) CPU D1508 @ 2.20GHz

* benchmark result before this commit
|            |    roundeven |   roundevenf |
|------------|--------------|--------------|
| duration   |  2.18208e+09 |  2.18258e+09 |
| iterations |  2.39932e+08 |  2.46924e+08 |
| max        | 96.378       | 98.035       |
| min        |  6.776       |  5.94        |
| mean       |  9.09456     |  8.83907     |

* benchmark result after this commit
|            |    roundeven |   roundevenf |
|------------|--------------|--------------|
| duration   |  2.17415e+09 |  2.17005e+09 |
| iterations |  3.56193e+08 |  4.09824e+08 |
| max        | 51.693       | 97.192       |
| min        |  5.926       |  5.093       |
| mean       |  6.10385     |  5.29507     |

I ran each tests about 20 times, and pick a stable result out.

Re: [PATCH v6 2/3] x86_64: roundeven with sse4.1 support

[Paul Zimmermann]

       Dear Shen-Ta,

thank you, this is a clear improvement! Sorry I cannot comment on the patch
itself since I'm not familiar with the redirect mechanism nor sse 4.1.

Paul

Re: [PATCH v6 2/3] x86_64: roundeven with sse4.1 support

[H.J. Lu]

On Fri, May 21, 2021 at 5:23 PM Shen-Ta Hsieh <ibmibmibm.tw@gmail.com> wrote:
>
> This patch adds support for the sse4.1 hardware floating point
> roundeven.
>
> Here is a benchmark result on my AMD Ryzen 9 3900X system:
>
> * benchmark result before this commit
> |            |    roundeven |   roundevenf |
> |------------|--------------|--------------|
> | duration   |  3.77659e+09 |  3.77504e+09 |
> | iterations |  3.97043e+08 |  4.36752e+08 |
> | max        | 83.714       | 58.861       |
> | min        |  7.144       |  6.27        |
> | mean       |  9.51179     |  8.64345     |
>
> * benchmark result after this commit
> |            |    roundeven |   roundevenf |
> |------------|--------------|--------------|
> | duration   |  3.76913e+09 |  3.76923e+09 |
> | iterations |  5.55921e+08 |  5.64822e+08 |
> | max        | 211.698      | 439.09       |
> | min        |  6.498       |  6.422       |
> | mean       |  6.77998     |  6.6733      |
>
> Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
> ---
>  sysdeps/x86_64/fpu/multiarch/Makefile         |  5 +--
>  sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c  |  2 ++
>  .../x86_64/fpu/multiarch/s_roundeven-sse4_1.S | 24 ++++++++++++++
>  sysdeps/x86_64/fpu/multiarch/s_roundeven.c    | 31 +++++++++++++++++++
>  sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c |  3 ++
>  .../fpu/multiarch/s_roundevenf-sse4_1.S       | 24 ++++++++++++++
>  sysdeps/x86_64/fpu/multiarch/s_roundevenf.c   | 31 +++++++++++++++++++
>  7 files changed, 118 insertions(+), 2 deletions(-)
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundeven.c
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundevenf.c
>
> diff --git a/sysdeps/x86_64/fpu/multiarch/Makefile b/sysdeps/x86_64/fpu/multiarch/Makefile
> index 57892c56bb..d425ffd6d3 100644
> --- a/sysdeps/x86_64/fpu/multiarch/Makefile
> +++ b/sysdeps/x86_64/fpu/multiarch/Makefile
> @@ -1,11 +1,12 @@
>  ifeq ($(subdir),math)
>  libm-sysdep_routines += s_floor-c s_ceil-c s_floorf-c s_ceilf-c \
>                         s_rint-c s_rintf-c s_nearbyint-c s_nearbyintf-c \
> -                       s_trunc-c s_truncf-c
> +                       s_roundeven-c s_roundevenf-c s_trunc-c s_truncf-c
>
>  libm-sysdep_routines += s_ceil-sse4_1 s_ceilf-sse4_1 s_floor-sse4_1 \
>                         s_floorf-sse4_1 s_nearbyint-sse4_1 \
> -                       s_nearbyintf-sse4_1 s_rint-sse4_1 s_rintf-sse4_1 \
> +                       s_nearbyintf-sse4_1 s_roundeven-sse4_1 \
> +                       s_roundevenf-sse4_1 s_rint-sse4_1 s_rintf-sse4_1 \
>                         s_trunc-sse4_1 s_truncf-sse4_1
>
>  libm-sysdep_routines += e_exp-fma e_log-fma e_pow-fma s_atan-fma \
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c b/sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c
> new file mode 100644
> index 0000000000..c7be43cb22
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c
> @@ -0,0 +1,2 @@
> +#define __roundeven __roundeven_c
> +#include <sysdeps/ieee754/dbl-64/s_roundeven.c>
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S b/sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S
> new file mode 100644
> index 0000000000..6ae8f6b1d3
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S
> @@ -0,0 +1,24 @@
> +/* Copyright (C) 2021 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>
> +
> +       .section .text.sse4.1,"ax",@progbits
> +ENTRY(__roundeven_sse41)
> +       roundsd $8, %xmm0, %xmm0
> +       ret
> +END(__roundeven_sse41)
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundeven.c b/sysdeps/x86_64/fpu/multiarch/s_roundeven.c
> new file mode 100644
> index 0000000000..d92eda652a
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundeven.c
> @@ -0,0 +1,31 @@
> +/* Multiple versions of __roundeven.
> +   Copyright (C) 2021 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>
> +
> +#define roundeven __redirect_roundeven
> +#define __roundeven __redirect___roundeven
> +#include <math.h>
> +#undef roundeven
> +#undef __roundeven
> +
> +#define SYMBOL_NAME roundeven
> +#include "ifunc-sse4_1.h"
> +
> +libc_ifunc_redirected (__redirect_roundeven, __roundeven, IFUNC_SELECTOR ());
> +libm_alias_double (__roundeven, roundeven)
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c
> new file mode 100644
> index 0000000000..72a6e7d1fb
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c
> @@ -0,0 +1,3 @@
> +#undef __roundevenf
> +#define __roundevenf __roundevenf_c
> +#include <sysdeps/ieee754/flt-32/s_roundevenf.c>
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S
> new file mode 100644
> index 0000000000..a76e10807e
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S
> @@ -0,0 +1,24 @@
> +/* Copyright (C) 2021 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>
> +
> +       .section .text.sse4.1,"ax",@progbits
> +ENTRY(__roundevenf_sse41)
> +       roundss $8, %xmm0, %xmm0
> +       ret
> +END(__roundevenf_sse41)
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundevenf.c b/sysdeps/x86_64/fpu/multiarch/s_roundevenf.c
> new file mode 100644
> index 0000000000..2ee196e68f
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundevenf.c
> @@ -0,0 +1,31 @@
> +/* Multiple versions of __roundevenf.
> +   Copyright (C) 2021 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-float.h>
> +
> +#define roundevenf __redirect_roundevenf
> +#define __roundevenf __redirect___roundevenf
> +#include <math.h>
> +#undef roundevenf
> +#undef __roundevenf
> +
> +#define SYMBOL_NAME roundevenf
> +#include "ifunc-sse4_1.h"
> +
> +libc_ifunc_redirected (__redirect_roundevenf, __roundevenf, IFUNC_SELECTOR ());
> +libm_alias_float (__roundeven, roundeven)
> --
> 2.31.1
>

LGTM.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

Thanks.

-- 
H.J.

Re: [PATCH v6 2/3] x86_64: roundeven with sse4.1 support

[Noah Goldstein]

On Fri, May 21, 2021 at 6:08 PM Shen-Ta Hsieh via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> This patch adds support for the sse4.1 hardware floating point
> roundeven.
>
> Here is a benchmark result on my AMD Ryzen 9 3900X system:
>
> * benchmark result before this commit
> |            |    roundeven |   roundevenf |
> |------------|--------------|--------------|
> | duration   |  3.77659e+09 |  3.77504e+09 |
> | iterations |  3.97043e+08 |  4.36752e+08 |
> | max        | 83.714       | 58.861       |
> | min        |  7.144       |  6.27        |
> | mean       |  9.51179     |  8.64345     |
>
> * benchmark result after this commit
> |            |    roundeven |   roundevenf |
> |------------|--------------|--------------|
> | duration   |  3.76913e+09 |  3.76923e+09 |
> | iterations |  5.55921e+08 |  5.64822e+08 |
> | max        | 211.698      | 439.09       |
> | min        |  6.498       |  6.422       |
> | mean       |  6.77998     |  6.6733      |
>
> Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>

You should probably update the commit message with the
new numbers and a mention that the relevant tests are
passing.

> ---
>  sysdeps/x86_64/fpu/multiarch/Makefile         |  5 +--
>  sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c  |  2 ++
>  .../x86_64/fpu/multiarch/s_roundeven-sse4_1.S | 24 ++++++++++++++
>  sysdeps/x86_64/fpu/multiarch/s_roundeven.c    | 31 +++++++++++++++++++
>  sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c |  3 ++
>  .../fpu/multiarch/s_roundevenf-sse4_1.S       | 24 ++++++++++++++
>  sysdeps/x86_64/fpu/multiarch/s_roundevenf.c   | 31 +++++++++++++++++++
>  7 files changed, 118 insertions(+), 2 deletions(-)
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundeven.c
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S
>  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_roundevenf.c
>
> diff --git a/sysdeps/x86_64/fpu/multiarch/Makefile b/sysdeps/x86_64/fpu/multiarch/Makefile
> index 57892c56bb..d425ffd6d3 100644
> --- a/sysdeps/x86_64/fpu/multiarch/Makefile
> +++ b/sysdeps/x86_64/fpu/multiarch/Makefile
> @@ -1,11 +1,12 @@
>  ifeq ($(subdir),math)
>  libm-sysdep_routines += s_floor-c s_ceil-c s_floorf-c s_ceilf-c \
>                         s_rint-c s_rintf-c s_nearbyint-c s_nearbyintf-c \
> -                       s_trunc-c s_truncf-c
> +                       s_roundeven-c s_roundevenf-c s_trunc-c s_truncf-c
>
>  libm-sysdep_routines += s_ceil-sse4_1 s_ceilf-sse4_1 s_floor-sse4_1 \
>                         s_floorf-sse4_1 s_nearbyint-sse4_1 \
> -                       s_nearbyintf-sse4_1 s_rint-sse4_1 s_rintf-sse4_1 \
> +                       s_nearbyintf-sse4_1 s_roundeven-sse4_1 \
> +                       s_roundevenf-sse4_1 s_rint-sse4_1 s_rintf-sse4_1 \
>                         s_trunc-sse4_1 s_truncf-sse4_1
>
>  libm-sysdep_routines += e_exp-fma e_log-fma e_pow-fma s_atan-fma \
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c b/sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c
> new file mode 100644
> index 0000000000..c7be43cb22
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundeven-c.c
> @@ -0,0 +1,2 @@
> +#define __roundeven __roundeven_c
> +#include <sysdeps/ieee754/dbl-64/s_roundeven.c>
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S b/sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S
> new file mode 100644
> index 0000000000..6ae8f6b1d3
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundeven-sse4_1.S
> @@ -0,0 +1,24 @@
> +/* Copyright (C) 2021 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>
> +
> +       .section .text.sse4.1,"ax",@progbits
> +ENTRY(__roundeven_sse41)
> +       roundsd $8, %xmm0, %xmm0
> +       ret
> +END(__roundeven_sse41)
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundeven.c b/sysdeps/x86_64/fpu/multiarch/s_roundeven.c
> new file mode 100644
> index 0000000000..d92eda652a
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundeven.c
> @@ -0,0 +1,31 @@
> +/* Multiple versions of __roundeven.
> +   Copyright (C) 2021 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>
> +
> +#define roundeven __redirect_roundeven
> +#define __roundeven __redirect___roundeven
> +#include <math.h>
> +#undef roundeven
> +#undef __roundeven
> +
> +#define SYMBOL_NAME roundeven
> +#include "ifunc-sse4_1.h"
> +
> +libc_ifunc_redirected (__redirect_roundeven, __roundeven, IFUNC_SELECTOR ());
> +libm_alias_double (__roundeven, roundeven)
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c
> new file mode 100644
> index 0000000000..72a6e7d1fb
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-c.c
> @@ -0,0 +1,3 @@
> +#undef __roundevenf
> +#define __roundevenf __roundevenf_c
> +#include <sysdeps/ieee754/flt-32/s_roundevenf.c>
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S
> new file mode 100644
> index 0000000000..a76e10807e
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundevenf-sse4_1.S
> @@ -0,0 +1,24 @@
> +/* Copyright (C) 2021 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>
> +
> +       .section .text.sse4.1,"ax",@progbits
> +ENTRY(__roundevenf_sse41)
> +       roundss $8, %xmm0, %xmm0
> +       ret
> +END(__roundevenf_sse41)
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_roundevenf.c b/sysdeps/x86_64/fpu/multiarch/s_roundevenf.c
> new file mode 100644
> index 0000000000..2ee196e68f
> --- /dev/null
> +++ b/sysdeps/x86_64/fpu/multiarch/s_roundevenf.c
> @@ -0,0 +1,31 @@
> +/* Multiple versions of __roundevenf.
> +   Copyright (C) 2021 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-float.h>
> +
> +#define roundevenf __redirect_roundevenf
> +#define __roundevenf __redirect___roundevenf
> +#include <math.h>
> +#undef roundevenf
> +#undef __roundevenf
> +
> +#define SYMBOL_NAME roundevenf
> +#include "ifunc-sse4_1.h"
> +
> +libc_ifunc_redirected (__redirect_roundevenf, __roundevenf, IFUNC_SELECTOR ());
> +libm_alias_float (__roundeven, roundeven)
> --
> 2.31.1
>

Re: [PATCH v6 1/3] math: redirect roundeven function

[H.J. Lu]

On Fri, May 21, 2021 at 5:23 PM Shen-Ta Hsieh <ibmibmibm.tw@gmail.com> wrote:
>
> This patch redirect roundeven function for futhermore changes.
>
> Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
> ---
>  include/math.h                             | 2 +-
>  sysdeps/ieee754/dbl-64/s_roundeven.c       | 4 +++-
>  sysdeps/ieee754/float128/s_roundevenf128.c | 1 +
>  sysdeps/ieee754/flt-32/s_roundevenf.c      | 3 +++
>  sysdeps/ieee754/ldbl-128/s_roundevenl.c    | 1 +
>  sysdeps/ieee754/ldbl-96/s_roundevenl.c     | 1 +
>  6 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/include/math.h b/include/math.h
> index e1c2a4eb64..b4772d3d3b 100644
> --- a/include/math.h
> +++ b/include/math.h
> @@ -38,7 +38,6 @@ libm_hidden_proto (__issignaling)
>  libm_hidden_proto (__issignalingf)
>  libm_hidden_proto (__exp)
>  libm_hidden_proto (__expf)
> -libm_hidden_proto (__roundeven)
>
>  #  if !defined __NO_LONG_DOUBLE_MATH \
>        && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0
> @@ -159,6 +158,7 @@ fabsf128 (_Float128 x)
>  MATH_REDIRECT (sqrt, "__ieee754_", MATH_REDIRECT_UNARY_ARGS)
>  MATH_REDIRECT (ceil, "__", MATH_REDIRECT_UNARY_ARGS)
>  MATH_REDIRECT (floor, "__", MATH_REDIRECT_UNARY_ARGS)
> +MATH_REDIRECT (roundeven, "__", MATH_REDIRECT_UNARY_ARGS)
>  MATH_REDIRECT (rint, "__", MATH_REDIRECT_UNARY_ARGS)
>  MATH_REDIRECT (trunc, "__", MATH_REDIRECT_UNARY_ARGS)
>  MATH_REDIRECT (round, "__", MATH_REDIRECT_UNARY_ARGS)
> diff --git a/sysdeps/ieee754/dbl-64/s_roundeven.c b/sysdeps/ieee754/dbl-64/s_roundeven.c
> index 943b2c634c..5deff3bb8a 100644
> --- a/sysdeps/ieee754/dbl-64/s_roundeven.c
> +++ b/sysdeps/ieee754/dbl-64/s_roundeven.c
> @@ -16,6 +16,7 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> +#define NO_MATH_REDIRECT
>  #include <math.h>
>  #include <math_private.h>
>  #include <libm-alias-double.h>
> @@ -66,5 +67,6 @@ __roundeven (double x)
>    INSERT_WORDS64 (x, ix);
>    return x;
>  }
> -hidden_def (__roundeven)
> +#ifndef __roundeven
>  libm_alias_double (__roundeven, roundeven)
> +#endif
> diff --git a/sysdeps/ieee754/float128/s_roundevenf128.c b/sysdeps/ieee754/float128/s_roundevenf128.c
> index 5a9b3f395f..e0faf727f6 100644
> --- a/sysdeps/ieee754/float128/s_roundevenf128.c
> +++ b/sysdeps/ieee754/float128/s_roundevenf128.c
> @@ -1,2 +1,3 @@
> +#define NO_MATH_REDIRECT
>  #include <float128_private.h>
>  #include "../ldbl-128/s_roundevenl.c"
> diff --git a/sysdeps/ieee754/flt-32/s_roundevenf.c b/sysdeps/ieee754/flt-32/s_roundevenf.c
> index ae54365bbe..2cc0d7b001 100644
> --- a/sysdeps/ieee754/flt-32/s_roundevenf.c
> +++ b/sysdeps/ieee754/flt-32/s_roundevenf.c
> @@ -17,6 +17,7 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> +#define NO_MATH_REDIRECT
>  #include <math.h>
>  #include <math_private.h>
>  #include <libm-alias-float.h>
> @@ -67,4 +68,6 @@ __roundevenf (float x)
>    SET_FLOAT_WORD (x, ix);
>    return x;
>  }
> +#ifndef __roundevenf
>  libm_alias_float (__roundeven, roundeven)
> +#endif
> diff --git a/sysdeps/ieee754/ldbl-128/s_roundevenl.c b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> index 02765be0e0..7c9c11fad2 100644
> --- a/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> +++ b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> @@ -17,6 +17,7 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> +#define NO_MATH_REDIRECT

Is this really needed?

>  #include <math.h>
>  #include <math_private.h>
>  #include <libm-alias-ldouble.h>
> diff --git a/sysdeps/ieee754/ldbl-96/s_roundevenl.c b/sysdeps/ieee754/ldbl-96/s_roundevenl.c
> index 8340116ed8..f826829c31 100644
> --- a/sysdeps/ieee754/ldbl-96/s_roundevenl.c
> +++ b/sysdeps/ieee754/ldbl-96/s_roundevenl.c
> @@ -17,6 +17,7 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> +#define NO_MATH_REDIRECT

Is this really needed?

>  #include <math.h>
>  #include <math_private.h>
>  #include <libm-alias-ldouble.h>
> --
> 2.31.1
>


-- 
H.J.

Re: [PATCH v6 3/3] Use GCC builtins for roundeven functions if desired.

[H.J. Lu]

On Fri, May 21, 2021 at 5:23 PM Shen-Ta Hsieh <ibmibmibm.tw@gmail.com> wrote:
>
> This patch is using the corresponding GCC builtin for roundevenf,
> roundeven and roundevenl if the USE_FUNCTION_BUILTIN macros are defined
> to one in math-use-builtins.h.
>
> These builtin functions is supported since GCC 10.
>
> The code of the generic implementation is not changed.
>
> Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
> ---
>  sysdeps/generic/math-use-builtins-roundeven.h | 4 ++++
>  sysdeps/generic/math-use-builtins.h           | 1 +
>  sysdeps/ieee754/dbl-64/s_roundeven.c          | 5 +++++
>  sysdeps/ieee754/flt-32/s_roundevenf.c         | 5 +++++
>  sysdeps/ieee754/ldbl-128/s_roundevenl.c       | 5 +++++
>  5 files changed, 20 insertions(+)
>  create mode 100644 sysdeps/generic/math-use-builtins-roundeven.h
>
> diff --git a/sysdeps/generic/math-use-builtins-roundeven.h b/sysdeps/generic/math-use-builtins-roundeven.h
> new file mode 100644
> index 0000000000..bd2e84c93f
> --- /dev/null
> +++ b/sysdeps/generic/math-use-builtins-roundeven.h
> @@ -0,0 +1,4 @@
> +#define USE_ROUNDEVEN_BUILTIN 0
> +#define USE_ROUNDEVENF_BUILTIN 0
> +#define USE_ROUNDEVENL_BUILTIN 0
> +#define USE_ROUNDEVENF128_BUILTIN 0
> diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
> index cc3e9f2201..19d2d1cf3c 100644
> --- a/sysdeps/generic/math-use-builtins.h
> +++ b/sysdeps/generic/math-use-builtins.h
> @@ -30,6 +30,7 @@
>  #include <math-use-builtins-ceil.h>
>  #include <math-use-builtins-trunc.h>
>  #include <math-use-builtins-round.h>
> +#include <math-use-builtins-roundeven.h>
>  #include <math-use-builtins-copysign.h>
>  #include <math-use-builtins-sqrt.h>
>  #include <math-use-builtins-fma.h>
> diff --git a/sysdeps/ieee754/dbl-64/s_roundeven.c b/sysdeps/ieee754/dbl-64/s_roundeven.c
> index 5deff3bb8a..88c051e9fe 100644
> --- a/sysdeps/ieee754/dbl-64/s_roundeven.c
> +++ b/sysdeps/ieee754/dbl-64/s_roundeven.c
> @@ -21,6 +21,7 @@
>  #include <math_private.h>
>  #include <libm-alias-double.h>
>  #include <stdint.h>
> +#include <math-use-builtins.h>
>
>  #define BIAS 0x3ff
>  #define MANT_DIG 53
> @@ -29,6 +30,9 @@
>  double
>  __roundeven (double x)
>  {
> +#if USE_ROUNDEVEN_BUILTIN
> +  return __builtin_roundeven (x);
> +#else
>    uint64_t ix, ux;
>    EXTRACT_WORDS64 (ix, x);
>    ux = ix & 0x7fffffffffffffffULL;
> @@ -66,6 +70,7 @@ __roundeven (double x)
>      ix &= 0x8000000000000000ULL;
>    INSERT_WORDS64 (x, ix);
>    return x;
> +#endif /* ! USE_ROUNDEVEN_BUILTIN  */
>  }
>  #ifndef __roundeven
>  libm_alias_double (__roundeven, roundeven)
> diff --git a/sysdeps/ieee754/flt-32/s_roundevenf.c b/sysdeps/ieee754/flt-32/s_roundevenf.c
> index 2cc0d7b001..4f568579d8 100644
> --- a/sysdeps/ieee754/flt-32/s_roundevenf.c
> +++ b/sysdeps/ieee754/flt-32/s_roundevenf.c
> @@ -21,6 +21,7 @@
>  #include <math.h>
>  #include <math_private.h>
>  #include <libm-alias-float.h>
> +#include <math-use-builtins.h>
>  #include <stdint.h>
>
>  #define BIAS 0x7f
> @@ -30,6 +31,9 @@
>  float
>  __roundevenf (float x)
>  {
> +#if USE_ROUNDEVENF_BUILTIN
> +  return __builtin_roundevenf (x);
> +#else
>    uint32_t ix, ux;
>    GET_FLOAT_WORD (ix, x);
>    ux = ix & 0x7fffffff;
> @@ -67,6 +71,7 @@ __roundevenf (float x)
>      ix &= 0x80000000;
>    SET_FLOAT_WORD (x, ix);
>    return x;
> +#endif /* ! USE_ROUNDEVENF_BUILTIN  */
>  }
>  #ifndef __roundevenf
>  libm_alias_float (__roundeven, roundeven)
> diff --git a/sysdeps/ieee754/ldbl-128/s_roundevenl.c b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> index 7c9c11fad2..afbf13d4f2 100644
> --- a/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> +++ b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> @@ -21,6 +21,7 @@
>  #include <math.h>
>  #include <math_private.h>
>  #include <libm-alias-ldouble.h>
> +#include <math-use-builtins.h>
>  #include <stdint.h>
>
>  #define BIAS 0x3fff
> @@ -30,6 +31,9 @@
>  _Float128
>  __roundevenl (_Float128 x)
>  {
> +#if USE_ROUNDEVENL_BUILTIN
> +  return __builtin_roundevenl (x);
> +#else
>    uint64_t hx, lx, uhx;
>    GET_LDOUBLE_WORDS64 (hx, lx, x);
>    uhx = hx & 0x7fffffffffffffffULL;
> @@ -101,5 +105,6 @@ __roundevenl (_Float128 x)
>      }
>    SET_LDOUBLE_WORDS64 (x, hx, lx);
>    return x;
> +#endif /* ! USE_ROUNDEVENL_BUILTIN  */
>  }
>  libm_alias_ldouble (__roundeven, roundeven)
> --
> 2.31.1
>

Do you need to map USE_ROUNDEVENL_BUILTIN to
USE_ROUNDEVENF128_BUILTIN in float128_private.h?

-- 
H.J.

Re: [PATCH v6 3/3] Use GCC builtins for roundeven functions if desired.

[謝昇達(Shen-Ta Hsieh)]

Oops, I missed that. I'll add this in this patch, thanks!

H.J. Lu <hjl.tools@gmail.com> 於 2021年5月24日 週一 上午3:04寫道：
>
> On Fri, May 21, 2021 at 5:23 PM Shen-Ta Hsieh <ibmibmibm.tw@gmail.com> wrote:
> >
> > This patch is using the corresponding GCC builtin for roundevenf,
> > roundeven and roundevenl if the USE_FUNCTION_BUILTIN macros are defined
> > to one in math-use-builtins.h.
> >
> > These builtin functions is supported since GCC 10.
> >
> > The code of the generic implementation is not changed.
> >
> > Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
> > ---
> >  sysdeps/generic/math-use-builtins-roundeven.h | 4 ++++
> >  sysdeps/generic/math-use-builtins.h           | 1 +
> >  sysdeps/ieee754/dbl-64/s_roundeven.c          | 5 +++++
> >  sysdeps/ieee754/flt-32/s_roundevenf.c         | 5 +++++
> >  sysdeps/ieee754/ldbl-128/s_roundevenl.c       | 5 +++++
> >  5 files changed, 20 insertions(+)
> >  create mode 100644 sysdeps/generic/math-use-builtins-roundeven.h
> >
> > diff --git a/sysdeps/generic/math-use-builtins-roundeven.h b/sysdeps/generic/math-use-builtins-roundeven.h
> > new file mode 100644
> > index 0000000000..bd2e84c93f
> > --- /dev/null
> > +++ b/sysdeps/generic/math-use-builtins-roundeven.h
> > @@ -0,0 +1,4 @@
> > +#define USE_ROUNDEVEN_BUILTIN 0
> > +#define USE_ROUNDEVENF_BUILTIN 0
> > +#define USE_ROUNDEVENL_BUILTIN 0
> > +#define USE_ROUNDEVENF128_BUILTIN 0
> > diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
> > index cc3e9f2201..19d2d1cf3c 100644
> > --- a/sysdeps/generic/math-use-builtins.h
> > +++ b/sysdeps/generic/math-use-builtins.h
> > @@ -30,6 +30,7 @@
> >  #include <math-use-builtins-ceil.h>
> >  #include <math-use-builtins-trunc.h>
> >  #include <math-use-builtins-round.h>
> > +#include <math-use-builtins-roundeven.h>
> >  #include <math-use-builtins-copysign.h>
> >  #include <math-use-builtins-sqrt.h>
> >  #include <math-use-builtins-fma.h>
> > diff --git a/sysdeps/ieee754/dbl-64/s_roundeven.c b/sysdeps/ieee754/dbl-64/s_roundeven.c
> > index 5deff3bb8a..88c051e9fe 100644
> > --- a/sysdeps/ieee754/dbl-64/s_roundeven.c
> > +++ b/sysdeps/ieee754/dbl-64/s_roundeven.c
> > @@ -21,6 +21,7 @@
> >  #include <math_private.h>
> >  #include <libm-alias-double.h>
> >  #include <stdint.h>
> > +#include <math-use-builtins.h>
> >
> >  #define BIAS 0x3ff
> >  #define MANT_DIG 53
> > @@ -29,6 +30,9 @@
> >  double
> >  __roundeven (double x)
> >  {
> > +#if USE_ROUNDEVEN_BUILTIN
> > +  return __builtin_roundeven (x);
> > +#else
> >    uint64_t ix, ux;
> >    EXTRACT_WORDS64 (ix, x);
> >    ux = ix & 0x7fffffffffffffffULL;
> > @@ -66,6 +70,7 @@ __roundeven (double x)
> >      ix &= 0x8000000000000000ULL;
> >    INSERT_WORDS64 (x, ix);
> >    return x;
> > +#endif /* ! USE_ROUNDEVEN_BUILTIN  */
> >  }
> >  #ifndef __roundeven
> >  libm_alias_double (__roundeven, roundeven)
> > diff --git a/sysdeps/ieee754/flt-32/s_roundevenf.c b/sysdeps/ieee754/flt-32/s_roundevenf.c
> > index 2cc0d7b001..4f568579d8 100644
> > --- a/sysdeps/ieee754/flt-32/s_roundevenf.c
> > +++ b/sysdeps/ieee754/flt-32/s_roundevenf.c
> > @@ -21,6 +21,7 @@
> >  #include <math.h>
> >  #include <math_private.h>
> >  #include <libm-alias-float.h>
> > +#include <math-use-builtins.h>
> >  #include <stdint.h>
> >
> >  #define BIAS 0x7f
> > @@ -30,6 +31,9 @@
> >  float
> >  __roundevenf (float x)
> >  {
> > +#if USE_ROUNDEVENF_BUILTIN
> > +  return __builtin_roundevenf (x);
> > +#else
> >    uint32_t ix, ux;
> >    GET_FLOAT_WORD (ix, x);
> >    ux = ix & 0x7fffffff;
> > @@ -67,6 +71,7 @@ __roundevenf (float x)
> >      ix &= 0x80000000;
> >    SET_FLOAT_WORD (x, ix);
> >    return x;
> > +#endif /* ! USE_ROUNDEVENF_BUILTIN  */
> >  }
> >  #ifndef __roundevenf
> >  libm_alias_float (__roundeven, roundeven)
> > diff --git a/sysdeps/ieee754/ldbl-128/s_roundevenl.c b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> > index 7c9c11fad2..afbf13d4f2 100644
> > --- a/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> > +++ b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> > @@ -21,6 +21,7 @@
> >  #include <math.h>
> >  #include <math_private.h>
> >  #include <libm-alias-ldouble.h>
> > +#include <math-use-builtins.h>
> >  #include <stdint.h>
> >
> >  #define BIAS 0x3fff
> > @@ -30,6 +31,9 @@
> >  _Float128
> >  __roundevenl (_Float128 x)
> >  {
> > +#if USE_ROUNDEVENL_BUILTIN
> > +  return __builtin_roundevenl (x);
> > +#else
> >    uint64_t hx, lx, uhx;
> >    GET_LDOUBLE_WORDS64 (hx, lx, x);
> >    uhx = hx & 0x7fffffffffffffffULL;
> > @@ -101,5 +105,6 @@ __roundevenl (_Float128 x)
> >      }
> >    SET_LDOUBLE_WORDS64 (x, hx, lx);
> >    return x;
> > +#endif /* ! USE_ROUNDEVENL_BUILTIN  */
> >  }
> >  libm_alias_ldouble (__roundeven, roundeven)
> > --
> > 2.31.1
> >
>
> Do you need to map USE_ROUNDEVENL_BUILTIN to
> USE_ROUNDEVENF128_BUILTIN in float128_private.h?
>
> --
> H.J.

Re: [PATCH v6 1/3] math: redirect roundeven function

[謝昇達(Shen-Ta Hsieh)]

I don't know if it is not needed, but I saw the same line at
"sysdeps/ieee754/ldbl-96/s_roundl.c", which is added by this commit:

https://sourceware.org/git/?p=glibc.git;a=commit;h=9755bc4686d8cd6a0e9539040b903e9e9291c319

H.J. Lu <hjl.tools@gmail.com> 於 2021年5月24日 週一 上午2:55寫道：
>
> On Fri, May 21, 2021 at 5:23 PM Shen-Ta Hsieh <ibmibmibm.tw@gmail.com> wrote:
> >
> > This patch redirect roundeven function for futhermore changes.
> >
> > Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
> > ---
> >  include/math.h                             | 2 +-
> >  sysdeps/ieee754/dbl-64/s_roundeven.c       | 4 +++-
> >  sysdeps/ieee754/float128/s_roundevenf128.c | 1 +
> >  sysdeps/ieee754/flt-32/s_roundevenf.c      | 3 +++
> >  sysdeps/ieee754/ldbl-128/s_roundevenl.c    | 1 +
> >  sysdeps/ieee754/ldbl-96/s_roundevenl.c     | 1 +
> >  6 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/math.h b/include/math.h
> > index e1c2a4eb64..b4772d3d3b 100644
> > --- a/include/math.h
> > +++ b/include/math.h
> > @@ -38,7 +38,6 @@ libm_hidden_proto (__issignaling)
> >  libm_hidden_proto (__issignalingf)
> >  libm_hidden_proto (__exp)
> >  libm_hidden_proto (__expf)
> > -libm_hidden_proto (__roundeven)
> >
> >  #  if !defined __NO_LONG_DOUBLE_MATH \
> >        && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0
> > @@ -159,6 +158,7 @@ fabsf128 (_Float128 x)
> >  MATH_REDIRECT (sqrt, "__ieee754_", MATH_REDIRECT_UNARY_ARGS)
> >  MATH_REDIRECT (ceil, "__", MATH_REDIRECT_UNARY_ARGS)
> >  MATH_REDIRECT (floor, "__", MATH_REDIRECT_UNARY_ARGS)
> > +MATH_REDIRECT (roundeven, "__", MATH_REDIRECT_UNARY_ARGS)
> >  MATH_REDIRECT (rint, "__", MATH_REDIRECT_UNARY_ARGS)
> >  MATH_REDIRECT (trunc, "__", MATH_REDIRECT_UNARY_ARGS)
> >  MATH_REDIRECT (round, "__", MATH_REDIRECT_UNARY_ARGS)
> > diff --git a/sysdeps/ieee754/dbl-64/s_roundeven.c b/sysdeps/ieee754/dbl-64/s_roundeven.c
> > index 943b2c634c..5deff3bb8a 100644
> > --- a/sysdeps/ieee754/dbl-64/s_roundeven.c
> > +++ b/sysdeps/ieee754/dbl-64/s_roundeven.c
> > @@ -16,6 +16,7 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > +#define NO_MATH_REDIRECT
> >  #include <math.h>
> >  #include <math_private.h>
> >  #include <libm-alias-double.h>
> > @@ -66,5 +67,6 @@ __roundeven (double x)
> >    INSERT_WORDS64 (x, ix);
> >    return x;
> >  }
> > -hidden_def (__roundeven)
> > +#ifndef __roundeven
> >  libm_alias_double (__roundeven, roundeven)
> > +#endif
> > diff --git a/sysdeps/ieee754/float128/s_roundevenf128.c b/sysdeps/ieee754/float128/s_roundevenf128.c
> > index 5a9b3f395f..e0faf727f6 100644
> > --- a/sysdeps/ieee754/float128/s_roundevenf128.c
> > +++ b/sysdeps/ieee754/float128/s_roundevenf128.c
> > @@ -1,2 +1,3 @@
> > +#define NO_MATH_REDIRECT
> >  #include <float128_private.h>
> >  #include "../ldbl-128/s_roundevenl.c"
> > diff --git a/sysdeps/ieee754/flt-32/s_roundevenf.c b/sysdeps/ieee754/flt-32/s_roundevenf.c
> > index ae54365bbe..2cc0d7b001 100644
> > --- a/sysdeps/ieee754/flt-32/s_roundevenf.c
> > +++ b/sysdeps/ieee754/flt-32/s_roundevenf.c
> > @@ -17,6 +17,7 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > +#define NO_MATH_REDIRECT
> >  #include <math.h>
> >  #include <math_private.h>
> >  #include <libm-alias-float.h>
> > @@ -67,4 +68,6 @@ __roundevenf (float x)
> >    SET_FLOAT_WORD (x, ix);
> >    return x;
> >  }
> > +#ifndef __roundevenf
> >  libm_alias_float (__roundeven, roundeven)
> > +#endif
> > diff --git a/sysdeps/ieee754/ldbl-128/s_roundevenl.c b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> > index 02765be0e0..7c9c11fad2 100644
> > --- a/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> > +++ b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> > @@ -17,6 +17,7 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > +#define NO_MATH_REDIRECT
>
> Is this really needed?
>
> >  #include <math.h>
> >  #include <math_private.h>
> >  #include <libm-alias-ldouble.h>
> > diff --git a/sysdeps/ieee754/ldbl-96/s_roundevenl.c b/sysdeps/ieee754/ldbl-96/s_roundevenl.c
> > index 8340116ed8..f826829c31 100644
> > --- a/sysdeps/ieee754/ldbl-96/s_roundevenl.c
> > +++ b/sysdeps/ieee754/ldbl-96/s_roundevenl.c
> > @@ -17,6 +17,7 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > +#define NO_MATH_REDIRECT
>
> Is this really needed?
>
> >  #include <math.h>
> >  #include <math_private.h>
> >  #include <libm-alias-ldouble.h>
> > --
> > 2.31.1
> >
>
>
> --
> H.J.