powerpc: Refactor modf{f}

The modf{f} optimization is not an optimization for ISA 2.07+.  This
patch move the IFUNC for powerpc64 only, move the power5+ to generic
location, and include the generic implementation for ISA 2.07+.

The performance changes are based on modf benchtests:

  * POWER9 - ppc64
  "modf": {
   "": {
    "duration": 4.97057e+09,
    "iterations": 1.00688e+09,
    "max": 28.76,
    "min": 4.912,
    "mean": 4.9366
   }
  }
  * POWER9 - power5+
  "modf": {
   "": {
    "duration": 4.98291e+09,
    "iterations": 9.32818e+08,
    "max": 15.058,
    "min": 5.107,
    "mean": 5.34178
   }
  }

  * POWER8 - ppc64
   "modf": {
   "": {
    "duration": 5.05329e+09,
    "iterations": 8.38814e+08,
    "max": 518.051,
    "min": 5.79,
    "mean": 6.02433
   }
  }
  * POWER8 - power5+
  "modf": {
   "": {
    "duration": 5.05573e+09,
    "iterations": 8.35254e+08,
    "max": 63.141,
    "min": 5.873,
    "mean": 6.05293
   }
  }

  * POWER7 - ppc64
  "modf": {
   "": {
    "duration": 4.89818e+09,
    "iterations": 1.08408e+09,
    "max": 57.556,
    "min": 3.953,
    "mean": 4.51827
   }
  }
  * POWER7 - power5+
  "modf": {
   "": {
    "duration": 4.83789e+09,
    "iterations": 1.33409e+09,
    "max": 46.608,
    "min": 2.224,
    "mean": 3.62636
   }
  }

Checked on powerpc-linux-gnu (built without --with-cpu, with
--with-cpu=power4 and with --with-cpu=power5+ and --disable-multi-arch),
powerpc64-linux-gnu (built without --with-cp and with --with-cpu=power5+
and --disable-multi-arch).

	* sysdeps/powerpc/power5+/fpu/s_modf.c: Move to ...
	* sysdeps/powerpc/fpu/s_modf.c: ... here.  Add ISA 2.07 optimization.
	* sysdeps/powerpc/power5+/fpu/s_modff.c: Move to ...
	* sysdeps/powerpc/fpu/s_modff.c: ... here.  Add ISA 2.07 optimization.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_modf-power5+.c:
	Adjust include.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_modff-power5+.c:
	Likewise.
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/Makefile (sysdep_calls,
	sysdep_routines): Add s_modf* objects.
	(CFLAGS-s_modf-power5+.c, CFLAGS-s_modff-power5+.c,
	CFLAGS-s_modf-ppc64.c, CFLAGS-s_modff-ppc64.c): New rule.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_modf-power5+.c: Move
	to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_modf-power5+.c:
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_modf-power5+.c: Movo
	to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_modf-power5+.c: Move
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_modf.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_modf.c: ... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_modff-power5+.c: Move
	to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_modff-power5+.c:
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_modff-ppc64.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_modff-ppc64.c:
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_modff.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_modff.c: ... here.

Reviewed-by: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>

2 files changed, 114 insertions, 0 deletions

diff --git a/sysdeps/powerpc/fpu/s_modf.c b/sysdeps/powerpc/fpu/s_modf.c
new file mode 100644
index 0000000000..2304fc48ed
--- /dev/null
+++ b/sysdeps/powerpc/fpu/s_modf.c
@@ -0,0 +1,59 @@
+/* Copyright (C) 2013-2019 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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+/* ISA 2.07 provides fast GPR to FP instruction (mfvsr{d,wz}) which make
+   generic implementation faster.  Also disables for old ISAs that do not
+   have ceil/floor instructions.  */
+#if defined(_ARCH_PWR8) || !defined(_ARCH_PWR5X)
+# include <sysdeps/ieee754/ldbl-opt/s_modf.c>
+#else
+# include <math.h>
+# include <math_ldbl_opt.h>
+# include <libm-alias-double.h>
+
+double
+__modf (double x, double *iptr)
+{
+  if (__builtin_isinf (x))
+    {
+      *iptr = x;
+      return copysign (0.0, x);
+    }
+  else if (__builtin_isnan (x))
+    {
+      *iptr = NAN;
+      return NAN;
+    }
+
+  if (x >= 0.0)
+    {
+      *iptr = floor (x);
+      return copysign (x - *iptr, x);
+    }
+  else
+    {
+      *iptr = ceil (x);
+      return copysign (x - *iptr, x);
+    }
+}
+# ifndef __modf
+libm_alias_double (__modf, modf)
+#  if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
+compat_symbol (libc, __modf, modfl, GLIBC_2_0);
+#  endif
+# endif
+#endif
diff --git a/sysdeps/powerpc/fpu/s_modff.c b/sysdeps/powerpc/fpu/s_modff.c
new file mode 100644
index 0000000000..2a0f114b20
--- /dev/null
+++ b/sysdeps/powerpc/fpu/s_modff.c
@@ -0,0 +1,55 @@
+/* Copyright (C) 2013-2019 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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+/* ISA 2.07 provides fast GPR to FP instruction (mfvsr{d,wz}) which make
+   generic implementation faster.  Also disables for old ISAs that do not
+   have ceil/floor instructions.  */
+#if defined(_ARCH_PWR8) || !defined(_ARCH_PWR5X)
+# include <sysdeps/ieee754/flt-32/s_modff.c>
+#else
+# include <math.h>
+# include <libm-alias-float.h>
+
+float
+__modff (float x, float *iptr)
+{
+  if (__builtin_isinff (x))
+    {
+      *iptr = x;
+      return copysignf (0.0, x);
+    }
+  else if (__builtin_isnanf (x))
+    {
+      *iptr = NAN;
+      return NAN;
+    }
+
+  if (x >= 0.0)
+    {
+      *iptr = floorf (x);
+      return copysignf (x - *iptr, x);
+    }
+  else
+    {
+      *iptr = ceilf (x);
+      return copysignf (x - *iptr, x);
+    }
+}
+# ifndef __modff
+libm_alias_float (__modf, modf)
+# endif
+#endif