i386: Replace assembly versions of e_powf with generic e_powf.c

This patch replaces i386 assembly versions of e_powf with generic
e_powf.c.  For workload-spec2017.wrf, on Nehalem, it improves
performance by:

                           Before            After     Improvement
reciprocal-throughput      230.855          78.3358       194%
latency                    231.685          94.1259       146%

On Skylake, it improves performance by:

                           Before            After     Improvement
reciprocal-throughput      239.858          47.4713       405%
latency                    247.57           93.8798       163%

On IvyBridge with --disable-multi-arch, it improves performance by:

                           Before            After     Improvement
reciprocal-throughput      269.078          63.3758       324%
latency                    271.473          102.091       165%

	* sysdeps/i386/fpu/e_powf.S: Removed.
	* sysdeps/i386/fpu/e_powf_log2_data.c: Likewise.
	* sysdeps/i386/fpu/w_powf.c: Likewise.
	* sysdeps/i386/fpu/libm-test-ulps: Updated for generic e_powf.c.
	* sysdeps/i386/i686/fpu/multiarch/libm-test-ulps: Likewise.
	* sysdeps/i386/i686/fpu/multiarch/Makefile (libm-sysdep_routines):
	Add e_powf-sse2.
	(CFLAGS-e_powf-sse2.c): New.
	* sysdeps/i386/i686/fpu/multiarch/e_powf-sse2.c: New file.
	* sysdeps/i386/i686/fpu/multiarch/e_powf.c: Likewise.

1 files changed, 43 insertions, 0 deletions

diff --git a/sysdeps/i386/i686/fpu/multiarch/e_powf.c b/sysdeps/i386/i686/fpu/multiarch/e_powf.c
new file mode 100644
index 0000000000..4dc4c87326
--- /dev/null
+++ b/sysdeps/i386/i686/fpu/multiarch/e_powf.c
@@ -0,0 +1,43 @@
+/* Multiple versions of powf.
+   Copyright (C) 2017 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
+   <http://www.gnu.org/licenses/>.  */
+
+#define powf __redirect_powf
+#define __DECL_SIMD___redirect_powf
+#include <math.h>
+#undef powf
+
+#define SYMBOL_NAME powf
+#include "ifunc-sse2.h"
+
+libc_ifunc_redirected (__redirect_powf, __powf, IFUNC_SELECTOR ());
+
+#ifdef SHARED
+__hidden_ver1 (__powf_ia32, __GI___powf, __redirect_powf)
+  __attribute__ ((visibility ("hidden")));
+
+# include <shlib-compat.h>
+versioned_symbol (libm, __powf, powf, GLIBC_2_27);
+#else
+weak_alias (__powf, powf)
+#endif
+
+strong_alias (__powf, __ieee754_powf)
+strong_alias (__powf, __powf_finite)
+
+#define __powf __powf_ia32
+#include <sysdeps/ieee754/flt-32/e_powf.c>