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.

ChangeLog

@@ -1,3 +1,17 @@
+2013-12-14  Ondřej Bílka  <neleai@seznam.cz>
+
+	[BZ #12100]
+	* sysdeps/x86_64/multiarch/strstr-sse2-unaligned.S: New file
+	* sysdeps/x86_64/multiarch/strstr-c.c: Moved to ...
+	* sysdeps/x86_64/multiarch/strstr.c: ... here.
+	(strstr): Add __strstr_sse2_unaligned ifunc.
+	* sysdeps/x86_64/multiarch/strcasestr-c.c: Moved to ...
+	* sysdeps/x86_64/multiarch/strcasestr.c ... here.
+	(strcasestr): Remove __strcasestr_sse42 ifunc.
+	* sysdeps/x86_64/multiarch/strcasestr-nonascii.c: Remove.
+	* sysdeps/x86_64/multiarch/ifunc-impl-list.c: Update.
+	* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Update.
+
 2013-12-14  Kaz Kojima  <kkojima@rr.iij4u.or.jp>
 
 	* sysdeps/sh/sh4/fpu/bits/fenv.h: Move to ...

NEWS

@@ -10,18 +10,18 @@ Version 2.19
 * The following bugs are resolved with this release:
 
   156, 387, 431, 832, 926, 2801, 4772, 6786, 6787, 6807, 6810, 7003, 9954,
-  10253, 10278, 11087, 11157, 11214, 12486, 13028, 13982, 13985, 14029,
-  14032, 14143, 14155, 14547, 14699, 14752, 14876, 14910, 15004, 15048,
-  15089, 15218, 15268, 15277, 15308, 15362, 15374, 15400, 15425, 15427,
-  15483, 15522, 15531, 15532, 15593, 15601, 15608, 15609, 15610, 15632,
-  15640, 15670, 15672, 15680, 15681, 15723, 15734, 15735, 15736, 15748,
-  15749, 15754, 15760, 15763, 15764, 15797, 15799, 15825, 15843, 15844,
-  15847, 15849, 15855, 15856, 15857, 15859, 15867, 15886, 15887, 15890,
-  15892, 15893, 15895, 15897, 15901, 15905, 15909, 15915, 15917, 15919,
-  15921, 15923, 15939, 15941, 15948, 15963, 15966, 15985, 15988, 15997,
-  16032, 16034, 16036, 16037, 16038, 16041, 16055, 16071, 16072, 16074,
-  16077, 16078, 16103, 16112, 16143, 16144, 16146, 16150, 16151, 16153,
-  16167, 16172, 16195, 16214, 16245, 16271, 16274, 16283, 16289.
+  10253, 10278, 11087, 11157, 11214, 12100, 12486, 13028, 13982, 13985,
+  14029, 14032, 14143, 14155, 14547, 14699, 14752, 14876, 14910, 15004,
+  15048, 15089, 15218, 15268, 15277, 15308, 15362, 15374, 15400, 15425,
+  15427, 15483, 15522, 15531, 15532, 15593, 15601, 15608, 15609, 15610,
+  15632, 15640, 15670, 15672, 15680, 15681, 15723, 15734, 15735, 15736,
+  15748, 15749, 15754, 15760, 15763, 15764, 15797, 15799, 15825, 15843,
+  15844, 15847, 15849, 15855, 15856, 15857, 15859, 15867, 15886, 15887,
+  15890, 15892, 15893, 15895, 15897, 15901, 15905, 15909, 15915, 15917,
+  15919, 15921, 15923, 15939, 15941, 15948, 15963, 15966, 15985, 15988,
+  15997, 16032, 16034, 16036, 16037, 16038, 16041, 16055, 16071, 16072,
+  16074, 16077, 16078, 16103, 16112, 16143, 16144, 16146, 16150, 16151,
+  16153, 16167, 16172, 16195, 16214, 16245, 16271, 16274, 16283, 16289.
 
 * The public headers no longer use __unused nor __block.  This change is to
   support compiling programs that are derived from BSD sources and use

sysdeps/x86_64/multiarch/Makefile

@@ -11,22 +11,19 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 \
 		   memcmp-sse4 memcpy-ssse3 \
 		   memcpy-sse2-unaligned mempcpy-ssse3 \
 		   memmove-ssse3 memcpy-ssse3-back mempcpy-ssse3-back \
-		   memmove-ssse3-back strcasestr-nonascii strcasecmp_l-ssse3 \
+		   memmove-ssse3-back strcasecmp_l-ssse3 \
 		   strncase_l-ssse3 strcat-ssse3 strncat-ssse3\
 		   strcpy-ssse3 strncpy-ssse3 stpcpy-ssse3 stpncpy-ssse3 \
 		   strcpy-sse2-unaligned strncpy-sse2-unaligned \
 		   stpcpy-sse2-unaligned stpncpy-sse2-unaligned \
 		   strcat-sse2-unaligned strncat-sse2-unaligned \
-		   strchr-sse2-no-bsf memcmp-ssse3
+		   strchr-sse2-no-bsf memcmp-ssse3 strstr-sse2-unaligned
 ifeq (yes,$(config-cflags-sse4))
-sysdep_routines += strcspn-c strpbrk-c strspn-c strstr-c strcasestr-c varshift
+sysdep_routines += strcspn-c strpbrk-c strspn-c varshift
 CFLAGS-varshift.c += -msse4
 CFLAGS-strcspn-c.c += -msse4
 CFLAGS-strpbrk-c.c += -msse4
 CFLAGS-strspn-c.c += -msse4
-CFLAGS-strstr.c += -msse4
-CFLAGS-strcasestr.c += -msse4
-CFLAGS-strcasestr-nonascii.c += -msse4
 endif
 endif
 

sysdeps/x86_64/multiarch/ifunc-impl-list.c

@@ -98,8 +98,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   /* Support sysdeps/x86_64/multiarch/strcasestr.c.  */
   IFUNC_IMPL (i, name, strcasestr,
-	      IFUNC_IMPL_ADD (array, i, strcasestr, HAS_SSE4_2,
-			      __strcasestr_sse42)
 	      IFUNC_IMPL_ADD (array, i, strcasestr, 1, __strcasestr_sse2))
 
   /* Support sysdeps/x86_64/multiarch/strcat.S.  */
@@ -184,7 +182,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   /* Support sysdeps/x86_64/multiarch/strstr-c.c.  */
   IFUNC_IMPL (i, name, strstr,
-	      IFUNC_IMPL_ADD (array, i, strstr, HAS_SSE4_2, __strstr_sse42)
+	      IFUNC_IMPL_ADD (array, i, strstr, 1, __strstr_sse2_unaligned)
 	      IFUNC_IMPL_ADD (array, i, strstr, 1, __strstr_sse2))
 
   /* Support sysdeps/x86_64/multiarch/wcscpy.S.  */

sysdeps/x86_64/multiarch/strcasestr.c

@@ -1,7 +1,13 @@
-extern char *__strcasestr_sse42_nonascii (const unsigned char *s1,
-					  const unsigned char *s2)
-  attribute_hidden;
+/* Multiple versions of strcasestr
+   All versions must be listed in ifunc-impl-list.c.  */
 
-#define USE_AS_STRCASESTR
-#define STRSTR_SSE42 __strcasestr_sse42
-#include "strstr.c"
+#include "init-arch.h"
+
+#define STRCASESTR __strcasestr_sse2
+
+#include "string/strcasestr.c"
+
+extern __typeof (__strcasestr_sse2) __strcasestr_sse2 attribute_hidden;
+
+libc_ifunc (__strcasestr,
+	    __strcasestr_sse2);