From 735a36828f349419379f15e942bfdf0c532d58eb Mon Sep 17 00:00:00 2001

From: Stefan Liebler <stli@linux.ibm.com>

Date: Wed, 11 Dec 2019 15:09:18 +0100

Subject: [PATCH 07/28] Use GCC builtins for nearbyint functions if desired.

This patch is using the corresponding GCC builtin for nearbyintf, nearbyint,

nearbintl and nearbyintf128 if the USE_FUNCTION_BUILTIN macros are defined to one

in math-use-builtins.h.

This is the case for s390 if build with at least --march=z196 --mzarch.

Otherwise the generic implementation is used.  The code of the generic

implementation is not changed.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

(cherry picked from commit ae3577f607b50bf3ce9b0877e43ad2508c9da61b)

Note: The TWO52 constants are now located in # ! USE_NEARBYINT_BUILTIN

---

 sysdeps/generic/math-use-builtins.h         | 29 ++++++++++++

 sysdeps/ieee754/dbl-64/s_nearbyint.c        | 17 ++++---

 sysdeps/ieee754/float128/float128_private.h |  4 ++

 sysdeps/ieee754/flt-32/s_nearbyintf.c       | 17 ++++---

 sysdeps/ieee754/ldbl-128/s_nearbyintl.c     | 17 ++++---

 sysdeps/s390/fpu/math-use-builtins.h        | 49 +++++++++++++++++++++

 6 files changed, 115 insertions(+), 18 deletions(-)

 create mode 100644 sysdeps/generic/math-use-builtins.h

 create mode 100644 sysdeps/s390/fpu/math-use-builtins.h

diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h

new file mode 100644

index 0000000000..e12490ed41

--- /dev/null

+++ b/sysdeps/generic/math-use-builtins.h

@@ -0,0 +1,29 @@

+/* Using math gcc builtins instead of generic implementation.  Generic version.

+   Copyright (C) 2019 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/>.  */

+

+#ifndef MATH_USE_BUILTINS_H

+#define MATH_USE_BUILTINS_H	1

+

+/* Define these macros to 1 to use __builtin_xyz instead of the

+   generic implementation.  */

+#define USE_NEARBYINT_BUILTIN 0

+#define USE_NEARBYINTF_BUILTIN 0

+#define USE_NEARBYINTL_BUILTIN 0

+#define USE_NEARBYINTF128_BUILTIN 0

+

+#endif /* math-use-builtins.h */

diff --git a/sysdeps/ieee754/dbl-64/s_nearbyint.c b/sysdeps/ieee754/dbl-64/s_nearbyint.c

index 903121d456..6b9f44dc8d 100644

--- a/sysdeps/ieee754/dbl-64/s_nearbyint.c

+++ b/sysdeps/ieee754/dbl-64/s_nearbyint.c

@@ -29,16 +29,20 @@ static char rcsid[] = "$NetBSD: s_rint.c,v 1.8 1995/05/10 20:48:04 jtc Exp $";

 #include <math-barriers.h>

 #include <math_private.h>

 #include <libm-alias-double.h>

-

-static const double

-  TWO52[2] = {

-  4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */

- -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */

-};

+#include <math-use-builtins.h>

 double

 __nearbyint (double x)

 {

+#if USE_NEARBYINT_BUILTIN

+  return __builtin_nearbyint (x);

+#else

+  /* Use generic implementation.  */

+  static const double

+    TWO52[2] = {

+		4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */

+		-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */

+  };

   fenv_t env;

   int32_t i0, j0, sx;

   double w, t;

@@ -72,5 +76,6 @@ __nearbyint (double x)

   math_force_eval (t);

   libc_fesetenv (&env;;

   return t;

+#endif /* ! USE_NEARBYINT_BUILTIN  */

 }

 libm_alias_double (__nearbyint, nearbyint)

diff --git a/sysdeps/ieee754/float128/float128_private.h b/sysdeps/ieee754/float128/float128_private.h

index 9dd15601e6..0bf6e8dee2 100644

--- a/sysdeps/ieee754/float128/float128_private.h

+++ b/sysdeps/ieee754/float128/float128_private.h

@@ -138,6 +138,9 @@

 #undef libm_alias_double_ldouble

 #define libm_alias_double_ldouble(func) libm_alias_float64_float128 (func)

+#include <math-use-builtins.h>

+#undef USE_NEARBYINTL_BUILTIN

+#define USE_NEARBYINTL_BUILTIN USE_NEARBYINTF128_BUILTIN

 /* IEEE function renames.  */

 #define __ieee754_acoshl __ieee754_acoshf128

@@ -339,6 +342,7 @@

 /* Builtin renames.  */

 #define __builtin_copysignl __builtin_copysignf128

 #define __builtin_signbitl __builtin_signbit

+#define __builtin_nearbyintl __builtin_nearbyintf128

 /* Get the constant suffix from bits/floatn-compat.h.  */

 #define L(x) __f128 (x)

diff --git a/sysdeps/ieee754/flt-32/s_nearbyintf.c b/sysdeps/ieee754/flt-32/s_nearbyintf.c

index 4dfe491f27..438dcae8cc 100644

--- a/sysdeps/ieee754/flt-32/s_nearbyintf.c

+++ b/sysdeps/ieee754/flt-32/s_nearbyintf.c

@@ -20,16 +20,20 @@

 #include <math-barriers.h>

 #include <math_private.h>

 #include <libm-alias-float.h>

-

-static const float

-TWO23[2]={

-  8.3886080000e+06, /* 0x4b000000 */

- -8.3886080000e+06, /* 0xcb000000 */

-};

+#include <math-use-builtins.h>

 float

 __nearbyintf(float x)

 {

+#if USE_NEARBYINTF_BUILTIN

+  return __builtin_nearbyintf (x);

+#else

+  /* Use generic implementation.  */

+  static const float

+    TWO23[2] = {

+		8.3886080000e+06, /* 0x4b000000 */

+		-8.3886080000e+06, /* 0xcb000000 */

+  };

 	fenv_t env;

 	int32_t i0,j0,sx;

 	float w,t;

@@ -57,5 +61,6 @@ __nearbyintf(float x)

 	math_force_eval (t);

 	libc_fesetenvf (&env;;

 	return t;

+#endif /* ! USE_NEARBYINT_BUILTIN  */

 }

 libm_alias_float (__nearbyint, nearbyint)

diff --git a/sysdeps/ieee754/ldbl-128/s_nearbyintl.c b/sysdeps/ieee754/ldbl-128/s_nearbyintl.c

index f044cb4334..a4ad8e82e5 100644

--- a/sysdeps/ieee754/ldbl-128/s_nearbyintl.c

+++ b/sysdeps/ieee754/ldbl-128/s_nearbyintl.c

@@ -28,15 +28,19 @@

 #include <math-barriers.h>

 #include <math_private.h>

 #include <libm-alias-ldouble.h>

-

-static const _Float128

-TWO112[2]={

-  L(5.19229685853482762853049632922009600E+33), /* 0x406F000000000000, 0 */

- L(-5.19229685853482762853049632922009600E+33)  /* 0xC06F000000000000, 0 */

-};

+#include <math-use-builtins.h>

 _Float128 __nearbyintl(_Float128 x)

 {

+#if USE_NEARBYINTL_BUILTIN

+  return __builtin_nearbyintl (x);

+#else

+  /* Use generic implementation.  */

+  static const _Float128

+    TWO112[2] = {

+		 L(5.19229685853482762853049632922009600E+33), /* 0x406F000000000000, 0 */

+		 L(-5.19229685853482762853049632922009600E+33)  /* 0xC06F000000000000, 0 */

+  };

 	fenv_t env;

 	int64_t i0,j0,sx;

 	uint64_t i1 __attribute__ ((unused));

@@ -65,5 +69,6 @@ _Float128 __nearbyintl(_Float128 x)

 	math_force_eval (t);

 	fesetenv (&env;;

 	return t;

+#endif /* ! USE_NEARBYINTL_BUILTIN  */

 }

 libm_alias_ldouble (__nearbyint, nearbyint)

diff --git a/sysdeps/s390/fpu/math-use-builtins.h b/sysdeps/s390/fpu/math-use-builtins.h

new file mode 100644

index 0000000000..7abbfb3b50

--- /dev/null

+++ b/sysdeps/s390/fpu/math-use-builtins.h

@@ -0,0 +1,49 @@

+/* Using math gcc builtins instead of generic implementation.  s390/s390x version.

+   Copyright (C) 2019 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/>.  */

+

+#ifndef MATH_USE_BUILTINS_S390_H

+#define MATH_USE_BUILTINS_S390_H	1

+

+#ifdef HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT

+

+# include <features.h> /* For __GNUC_PREREQ.  */

+

+/* GCC emits the z196 zarch "load fp integer" instructions for these

+   builtins if build with at least --march=z196 -mzarch.  Otherwise a

+   function call to libc is emitted.  */

+# define USE_NEARBYINT_BUILTIN 1

+# define USE_NEARBYINTF_BUILTIN 1

+# define USE_NEARBYINTL_BUILTIN 1

+

+# if __GNUC_PREREQ (8, 0)

+#  define USE_NEARBYINTF128_BUILTIN 1

+# else

+#  define USE_NEARBYINTF128_BUILTIN 0

+# endif

+

+#else

+

+/* Disable the builtins if we do not have the z196 zarch instructions.  */

+# define USE_NEARBYINT_BUILTIN 0

+# define USE_NEARBYINTF_BUILTIN 0

+# define USE_NEARBYINTL_BUILTIN 0

+# define USE_NEARBYINTF128_BUILTIN 0

+

+#endif /* ! HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT  */

+

+#endif /* math-use-builtins.h */

-- 

2.18.2