Add strstr with unaligned loads. Fixes bug 12100.

A sse42 version of strstr used pcmpistr instruction which is quite
ineffective. A faster way is look for pairs of characters which is uses
sse2, is faster than pcmpistr and for real strings a pairs we look for
are relatively rare.

For linear time complexity we use buy or rent technique which switches
to two-way algorithm when superlinear behaviour is detected.

1 files changed, 0 insertions, 47 deletions

diff --git a/sysdeps/x86_64/multiarch/strstr-c.c b/sysdeps/x86_64/multiarch/strstr-c.c
deleted file mode 100644
index 42bbe48172..0000000000
--- a/sysdeps/x86_64/multiarch/strstr-c.c
+++ /dev/null
@@ -1,47 +0,0 @@
-/* Multiple versions of strstr.
-   All versions must be listed in ifunc-impl-list.c.
-   Copyright (C) 2012-2013 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/>.  */
-
-/* Redefine strstr so that the compiler won't complain about the type
-   mismatch with the IFUNC selector in strong_alias, below.  */
-#undef  strstr
-#define strstr __redirect_strstr
-#include <string.h>
-#undef  strstr
-
-#define STRSTR __strstr_sse2
-#ifdef SHARED
-# undef libc_hidden_builtin_def
-# define libc_hidden_builtin_def(name) \
-  __hidden_ver1 (__strstr_sse2, __GI_strstr, __strstr_sse2);
-#endif
-
-#include "string/strstr.c"
-
-extern __typeof (__redirect_strstr) __strstr_sse42 attribute_hidden;
-extern __typeof (__redirect_strstr) __strstr_sse2 attribute_hidden;
-
-#include "init-arch.h"
-
-/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
-   ifunc symbol properly.  */
-extern __typeof (__redirect_strstr) __libc_strstr;
-libc_ifunc (__libc_strstr, HAS_SSE4_2 ? __strstr_sse42 : __strstr_sse2)
-
-#undef strstr
-strong_alias (__libc_strstr, strstr)