powerpc: strstr optimization

This patch optimizes strstr function for power >= 7 systems.  Performance
gain is obtained using aligned memory access and usage of cmpb
instruction for quicker comparison.  The average improvement of this
optimization is ~40%.  Tested on ppc64 and ppc64le.

2015-07-16  Rajalakshmi Srinivasaraghavan  <raji@linux.vnet.ibm.com>

	* sysdeps/powerpc/powerpc64/multiarch/Makefile: Add strstr().
	* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c: Likewise.
	* sysdeps/powerpc/powerpc64/power7/strstr.S: New File.
	* sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S: New File.
	* sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c: New File.
	* sysdeps/powerpc/powerpc64/multiarch/strstr.c: New File.

1 files changed, 29 insertions, 0 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c b/sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c
new file mode 100644
index 0000000000..7fa2ace589
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c
@@ -0,0 +1,29 @@
+/* Copyright (C) 2015 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 <string.h>
+
+#define STRSTR __strstr_ppc
+#if IS_IN (libc) && defined(SHARED)
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(name) \
+  __hidden_ver1(__strstr_ppc, __GI_strstr, __strstr_ppc);
+#endif
+
+extern __typeof (strstr) __strstr_ppc attribute_hidden;
+
+#include <string/strstr.c>