powerpc: Add optimized P8 strspn

This utilizes vectors and bitmasks.  For small needle, large
haystack, the performance improvement is upto 8x.  For short
strings (0-4B), the cost of computing the bitmask dominates,
and is a tad slower.

1 files changed, 40 insertions, 0 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/strspn-power8.S b/sysdeps/powerpc/powerpc64/multiarch/strspn-power8.S
new file mode 100644
index 0000000..86a4e09
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strspn-power8.S
@@ -0,0 +1,40 @@
+/* Optimized strspn 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(__strspn_power8)					\
+  .align ALIGNARG(alignt);					\
+  EALIGN_W_##words;						\
+  BODY_LABEL(__strspn_power8):					\
+  cfi_startproc;						\
+  LOCALENTRY(__strspn_power8)
+
+#undef END
+#define END(name)						\
+  cfi_endproc;							\
+  TRACEBACK(__strspn_power8)					\
+  END_2(__strspn_power8)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#include <sysdeps/powerpc/powerpc64/power8/strspn.S>