powerpc: strcasestr optmization for power8

This patch optimizes strcasestr function for power >= 8 systems.  The average
improvement of this optimization is ~40% and compares 16 bytes at a time
using vector instructions.  This patch is tested on powerpc64 and powerpc64le.

1 files changed, 49 insertions, 0 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcasestr-power8.S b/sysdeps/powerpc/powerpc64/multiarch/strcasestr-power8.S
new file mode 100644
index 0000000000..c77ff9f9ee
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strcasestr-power8.S
@@ -0,0 +1,49 @@
+/* Optimized strcasestr implementation for POWER8.
+   Copyright (C) 2016 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 <sysdep.h>
+
+#undef EALIGN
+#define EALIGN(name, alignt, words)				\
+  .section ".text";						\
+  ENTRY_2(__strcasestr_power8)					\
+  .align ALIGNARG(alignt);					\
+  EALIGN_W_##words;						\
+  BODY_LABEL(__strcasestr_power8):				\
+  cfi_startproc;						\
+  LOCALENTRY(__strcasestr_power8)
+
+#undef END
+#define END(name)						\
+  cfi_endproc;							\
+  TRACEBACK(__strcasestr_power8)				\
+  END_2(__strcasestr_power8)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+/* The following definitions are used in strcasestr optimization.  */
+
+/* strlen is used to calculate len of r4.  */
+#define STRLEN __strlen_power8
+/* strnlen is used to check if len of r3 is more than r4.  */
+#define STRNLEN __strnlen_power7
+/* strchr is used to check if first char of r4 is present in r3.  */
+#define STRCHR __strchr_power7
+
+#include <sysdeps/powerpc/powerpc64/power8/strcasestr.S>