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.

5 files changed, 117 insertions, 1 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index 17265bd275..3b0e3a0117 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -19,7 +19,7 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
 		   strcmp-power8 strcmp-power7 strcmp-ppc64 \
 		   strcat-power8 strcat-power7 strcat-ppc64 \
 		   memmove-power7 memmove-ppc64 wordcopy-ppc64 bcopy-ppc64 \
-		   strncpy-power8
+		   strncpy-power8 strstr-power7 strstr-ppc64
 
 CFLAGS-strncase-power7.c += -mcpu=power7 -funroll-loops
 CFLAGS-strncase_l-power7.c += -mcpu=power7 -funroll-loops
diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
index f5fdea5dd4..364385b1cc 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -322,5 +322,14 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, strcat, 1,
 			     __strcat_ppc))
 
+  /* Support sysdeps/powerpc/powerpc64/multiarch/strstr.c.  */
+  IFUNC_IMPL (i, name, strstr,
+             IFUNC_IMPL_ADD (array, i, strstr,
+                             hwcap & PPC_FEATURE_HAS_VSX,
+                             __strstr_power7)
+             IFUNC_IMPL_ADD (array, i, strstr, 1,
+                             __strstr_ppc))
+
+
   return i;
 }
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S b/sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S
new file mode 100644
index 0000000000..94ce95b821
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S
@@ -0,0 +1,44 @@
+/* Optimized strstr implementation for POWER7.
+   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 <sysdep.h>
+
+#undef EALIGN
+#define EALIGN(name, alignt, words)				\
+  .section ".text";						\
+  ENTRY_2(__strstr_power7)					\
+  .align ALIGNARG(alignt);					\
+  EALIGN_W_##words;						\
+  BODY_LABEL(__strstr_power7):					\
+  cfi_startproc;						\
+  LOCALENTRY(__strstr_power7)
+
+#undef END
+#define END(name)						\
+  cfi_endproc;							\
+  TRACEBACK(__strstr_power7)					\
+  END_2(__strstr_power7)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#define STRLEN __strlen_power7
+#define STRNLEN __strnlen_power7
+#define STRCHR __strchr_power7
+
+#include <sysdeps/powerpc/powerpc64/power7/strstr.S>
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>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strstr.c b/sysdeps/powerpc/powerpc64/multiarch/strstr.c
new file mode 100644
index 0000000000..2be764660a
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strstr.c
@@ -0,0 +1,34 @@
+/* Multiple versions of strstr. PowerPC64 version.
+   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/>.  */
+
+/* Define multiple versions only for definition in libc.  */
+#if IS_IN (libc)
+# include <string.h>
+# include <shlib-compat.h>
+# include "init-arch.h"
+
+extern __typeof (strstr) __strstr_ppc attribute_hidden;
+extern __typeof (strstr) __strstr_power7 attribute_hidden;
+
+/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
+   ifunc symbol properly.  */
+libc_ifunc (strstr,
+            (hwcap & PPC_FEATURE_HAS_VSX)
+            ? __strstr_power7
+            : __strstr_ppc);
+#endif