PowerPC: strncat optimization for PPC64

The optimization is achieved by following techniques:
1. Doubleword aligned memory access and compares using
   cmpb instruction.
2. Loop unrolling for byte load/store.
3. CPU pre-fetch to avoid cache miss.

5 files changed, 111 insertions, 1 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index d09f2e3e5d..a03569ec80 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -14,7 +14,7 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
 		   wcsrchr-ppc64 wcscpy-power7 wcscpy-power6 wcscpy-ppc64 \
 		   wordcopy-power7 wordcopy-power6 wordcopy-ppc64 \
 		   strcpy-power7 strcpy-ppc64 stpcpy-power7 stpcpy-ppc64 \
-		   strrchr-power7 strrchr-ppc64
+		   strrchr-power7 strrchr-ppc64 strncat-power7 strncat-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 8789483780..11a3bed9a5 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -246,5 +246,13 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, strrchr, 1,
 			      __strrchr_ppc))
 
+  /* Support sysdeps/powerpc/powerpc64/multiarch/strncat.c.  */
+  IFUNC_IMPL (i, name, strncat,
+	      IFUNC_IMPL_ADD (array, i, strncat,
+			      hwcap & PPC_FEATURE_HAS_VSX,
+			      __strncat_power7)
+	      IFUNC_IMPL_ADD (array, i, strncat, 1,
+			      __strncat_ppc))
+
   return i;
 }
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncat-power7.S b/sysdeps/powerpc/powerpc64/multiarch/strncat-power7.S
new file mode 100644
index 0000000000..ead4a9afbe
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncat-power7.S
@@ -0,0 +1,42 @@
+/* Optimized strncat implementation for POWER7.
+   Copyright (C) 2014 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(__strncat_power7)					\
+  .align ALIGNARG(alignt);					\
+  EALIGN_W_##words;						\
+  BODY_LABEL(__strncat_power7):					\
+  cfi_startproc;						\
+  LOCALENTRY(__strncat_power7)
+
+#undef END
+#define END(name)						\
+  cfi_endproc;							\
+  TRACEBACK(__strncat_power7)					\
+  END_2(__strncat_power7)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#define STRLEN __strlen_power7
+
+#include <sysdeps/powerpc/powerpc64/power7/strncat.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncat-ppc64.c b/sysdeps/powerpc/powerpc64/multiarch/strncat-ppc64.c
new file mode 100644
index 0000000000..3058c0a802
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncat-ppc64.c
@@ -0,0 +1,29 @@
+/* Copyright (C) 2014 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 STRNCAT __strncat_ppc
+#ifdef SHARED
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(name) \
+  __hidden_ver1 (__strncat_ppc, __GI_strncat, __strncat_ppc);
+#endif
+
+extern __typeof (strncat) __strncat_ppc attribute_hidden;
+
+#include <string/strncat.c>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncat.c b/sysdeps/powerpc/powerpc64/multiarch/strncat.c
new file mode 100644
index 0000000000..db98ec1a00
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncat.c
@@ -0,0 +1,31 @@
+/* Multiple versions of strncat. PowerPC64 version.
+   Copyright (C) 2014 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/>.  */
+
+#ifndef NOT_IN_libc
+# include <string.h>
+# include <shlib-compat.h>
+# include "init-arch.h"
+
+extern __typeof (strncat) __strncat_ppc attribute_hidden;
+extern __typeof (strncat) __strncat_power7 attribute_hidden;
+
+libc_ifunc (strncat,
+            (hwcap & PPC_FEATURE_HAS_VSX)
+            ? __strncat_power7
+            : __strncat_ppc);
+#endif