x86-64: Add cosf with FMA

On Skylake, bench-cosf reports performance improvement:

            Before        After         Improvement
max        135.362       94.552            43%
min        8.532         7.688             11%
mean       17.1446       11.8128           45%

	* sysdeps/x86_64/fpu/multiarch/Makefile (libm-sysdep_routines):
	Add s_cosf-sse2 and s_cosf-fma.
	(CFLAGS-s_cosf-fma.c): New.
	* sysdeps/x86_64/fpu/multiarch/s_cosf-fma.c: New file.
	* sysdeps/x86_64/fpu/multiarch/s_cosf-sse2.c: Likewise.
	* sysdeps/x86_64/fpu/multiarch/s_cosf.c: Likewise.

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

1 files changed, 28 insertions, 0 deletions

diff --git a/sysdeps/x86_64/fpu/multiarch/s_cosf.c b/sysdeps/x86_64/fpu/multiarch/s_cosf.c
new file mode 100644
index 0000000000..356c3b63c7
--- /dev/null
+++ b/sysdeps/x86_64/fpu/multiarch/s_cosf.c
@@ -0,0 +1,28 @@
+/* Multiple versions of cosf.
+   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/>.  */
+
+#include <libm-alias-float.h>
+
+extern float __redirect_cosf (float);
+
+#define SYMBOL_NAME cosf
+#include "ifunc-fma.h"
+
+libc_ifunc_redirected (__redirect_cosf, __cosf, IFUNC_SELECTOR ());
+
+libm_alias_float (__cos, cos)