PowerPC: strncpy/stpncpy optimization for PPC64/POWER7

The optimization is achieved by following techniques:
  > data alignment [gain from aligned memory access on read/write]
  > POWER7 gains performance with loop unrolling/unwinding
    [gain by reduction of branch penalty].
  > zero padding done by calling optimized memset

1 files changed, 33 insertions, 0 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncpy-ppc64.c b/sysdeps/powerpc/powerpc64/multiarch/strncpy-ppc64.c
new file mode 100644
index 0000000000..e3111d259c
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncpy-ppc64.c
@@ -0,0 +1,33 @@
+/* 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 STRNCPY __strncpy_ppc
+#undef weak_alias
+#define weak_alias(name, aliasname) \
+  extern __typeof (__strncpy_ppc) aliasname \
+    __attribute__ ((weak, alias ("__strncpy_ppc")));
+#if !defined(NOT_IN_libc) && defined(SHARED)
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(name) \
+  __hidden_ver1(__strncpy_ppc, __GI_strncpy, __strncpy_ppc);
+#endif
+
+extern __typeof (strncpy) __strncpy_ppc attribute_hidden;
+
+#include <string/strncpy.c>