powerpc: refactor logb{f,l}

The power7 logb implementation does not show a performance gain on
ISA 2.07+ chips with faster floating-point to GRP instructions
(currently POWER8 and POWER9).

This patch moves the POWER7 implementation to generic one and enables
it for POWER7.  It also add some cleanup to use inline floating-point
number instead of define them using static const.

The performance difference is for POWER9:

  - Without patch:
  "logb": {
   "subnormal": {
    "duration": 4.99202e+09,
    "iterations": 8.83662e+08,
    "max": 75.194,
    "min": 5.501,
    "mean": 5.64925
   },
   "normal": {
    "duration": 4.97063e+09,
    "iterations": 9.97094e+08,
    "max": 46.489,
    "min": 4.956,
    "mean": 4.98512
   }
  }

  - With patch:
  "logb": {
   "subnormal": {
    "duration": 4.97226e+09,
    "iterations": 9.92036e+08,
    "max": 77.209,
    "min": 4.892,
    "mean": 5.01218
   },
   "normal": {
    "duration": 4.96192e+09,
    "iterations": 1.07545e+09,
    "max": 12.361,
    "min": 4.593,
    "mean": 4.61382
   }
  }

The ifunc implementation is also enabled only for powerpc64.

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/power7/fpu/s_logb.c: Move to ...
	* sysdeps/powerpc/fpu/s_logb.c: ... here.  Use inline FP constants.
	* sysdeps/powerpc/power7/fpu/s_logbf.c: Move to ...
	* sysdeps/powerpc/fpu/s_logbf.c: ... here.  Use inline FP constants.
	* sysdeps/powerpc/power7/fpu/s_logbl.c: Move to ...
	* sysdeps/powerpc/fpu/s_logbl.c: ... here.  Use inline FP constants.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb-power7.c:
	Adjust implementation path.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbf-power7.c:
	Adjust implementation path.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbl-power7.c:
	Adjust implementation path.
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/Makefile
	(libm-sysdep_routines): Add s_log* objects.
	(CFLAGS-s_logbf-power7.c, CFLAGS-s_logbl-power7.c,
	CFLAGS-s_logb-power7.c): New fule.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logb-power7.c: Move
	to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_logb-power7.c:
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logb-ppc64.c: Move
	to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_logb-ppc64.c:
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logb.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_logb.c: ... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logbf-power7.c: Move
	to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_logbf-power7.c:
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logbf-ppc64.c: Move
	to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_logbf-ppc64.c:
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logbf.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_logbf.c: ... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logbl-power7.c: Move
	to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_logbl-power7.c:
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logbl-ppc64.c: Move
	to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_logbl-ppc64.c:
	... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logbl.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_logbl.c: ... here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile: Remove file.
	* sysdeps/powerpc/powerpc64/power7/fpu/s_logb.c: Remove file.
	* sysdeps/powerpc/powerpc64/power7/fpu/s_logbf.c: Likewise.
	* sysdeps/powerpc/powerpc64/power7/fpu/s_logbl.c: Likewise.

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

3 files changed, 3 insertions, 21 deletions

diff --git a/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb-power7.c b/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb-power7.c
index 812771ac2e..c893ebcf29 100644
--- a/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb-power7.c
+++ b/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb-power7.c
@@ -16,16 +16,5 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <math.h>
-#include <math_ldbl_opt.h>
-
-#undef weak_alias
-#define weak_alias(a, b)
-#undef strong_alias
-#define strong_alias(a, b)
-#undef compat_symbol
-#define compat_symbol(lib, name, alias, ver)
-
 #define __logb __logb_power7
-
-#include <sysdeps/powerpc/power7/fpu/s_logb.c>
+#include <sysdeps/powerpc/fpu/s_logb.c>
diff --git a/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbf-power7.c b/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbf-power7.c
index 62c2318421..059c53bce2 100644
--- a/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbf-power7.c
+++ b/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbf-power7.c
@@ -16,11 +16,5 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <math.h>
-
-#undef weak_alias
-#define weak_alias(a, b)
-
 #define __logbf __logbf_power7
-
-#include <sysdeps/powerpc/power7/fpu/s_logbf.c>
+#include <sysdeps/powerpc/fpu/s_logbf.c>
diff --git a/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbl-power7.c b/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbl-power7.c
index c4fe590c6c..22a6ffb064 100644
--- a/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbl-power7.c
+++ b/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logbl-power7.c
@@ -17,5 +17,4 @@
    <http://www.gnu.org/licenses/>.  */
 
 #define __logbl __logbl_power7
-
-#include <sysdeps/powerpc/power7/fpu/s_logbl.c>
+#include <sysdeps/powerpc/fpu/s_logbl.c>