[PATCH 3/4] Improve generic strpbrk performance

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

With now a faster strcspn implementation, it is faster to just use
it with some return tests than reimplementing strpbrk itself.
As for strcspn optimization, it is generally at least 10 times faster
than the existing implementation on bench-strspn on a few AArch64
implementations.

Also the string/bits/string2.h inlines make no longer sense, as current
implementation will already implement most of the optimizations.

Tested on x86_64, i386, and aarch64.

	* string/strpbrk.c (strpbrk): Rewrite function.
	* string/bits/string2.h (strpbrk): Use __builtin_strpbrk.
---
 ChangeLog             |  3 +++
 string/bits/string2.h | 41 ++++++-----------------------------------
 string/strpbrk.c      | 12 ++----------
 3 files changed, 11 insertions(+), 45 deletions(-)

diff --git a/string/bits/string2.h b/string/bits/string2.h
index a1684eb..76a179a 100644
--- a/string/bits/string2.h
+++ b/string/bits/string2.h
@@ -999,43 +999,14 @@ __strspn_c3 (const char *__s, int __accept1, int __accept2, int __accept3)
 
 
 /* Find the first occurrence in S of any character in ACCEPT.  */
-#if !defined _HAVE_STRING_ARCH_strpbrk || defined _FORCE_INLINES
-# ifndef _HAVE_STRING_ARCH_strpbrk
-#  if __GNUC_PREREQ (3, 2)
-#   define strpbrk(s, accept) \
-  __extension__								      \
-  ({ char __a0, __a1, __a2;						      \
-     (__builtin_constant_p (accept) && __string2_1bptr_p (accept)	      \
-      ? ((__builtin_constant_p (s) && __string2_1bptr_p (s))		      \
-	 ? __builtin_strpbrk (s, accept)				      \
-	 : ((__a0 = ((const char  *) (accept))[0], __a0 == '\0')	      \
-	    ? ((void) (s), (char *) NULL)				      \
-	    : ((__a1 = ((const char *) (accept))[1], __a1 == '\0')	      \
-	       ? __builtin_strchr (s, __a0)				      \
-	       : ((__a2 = ((const char *) (accept))[2], __a2 == '\0')	      \
-		  ? __strpbrk_c2 (s, __a0, __a1)			      \
-		  : (((const char *) (accept))[3] == '\0'		      \
-		     ? __strpbrk_c3 (s, __a0, __a1, __a2)		      \
-		     : __builtin_strpbrk (s, accept))))))		      \
-      : __builtin_strpbrk (s, accept)); })
-#  else
-#   define strpbrk(s, accept) \
-  __extension__								      \
-  ({ char __a0, __a1, __a2;						      \
-     (__builtin_constant_p (accept) && __string2_1bptr_p (accept)	      \
-      ? ((__a0 = ((const char  *) (accept))[0], __a0 == '\0')		      \
-	 ? ((void) (s), (char *) NULL)					      \
-	 : ((__a1 = ((const char *) (accept))[1], __a1 == '\0')		      \
-	    ? strchr (s, __a0)						      \
-	    : ((__a2 = ((const char *) (accept))[2], __a2 == '\0')	      \
-	       ? __strpbrk_c2 (s, __a0, __a1)				      \
-	       : (((const char *) (accept))[3] == '\0'			      \
-		  ? __strpbrk_c3 (s, __a0, __a1, __a2)			      \
-		  : strpbrk (s, accept)))))				      \
-      : strpbrk (s, accept)); })
-#  endif
+#ifndef _HAVE_STRING_ARCH_strpbrk
+# if __GNUC_PREREQ (3, 2)
+#  define strpbrk(s, accept) __builtin_strpbrk (s, accept)
 # endif
 
+/* The inline functions are not used from GLIBC 2.24 and forward, however
+   they are required to provide the symbols through string-inlines.c
+   (if inlining is not possible for compatibility reasons).  */
 __STRING_INLINE char *__strpbrk_c2 (const char *__s, int __accept1,
 				    int __accept2);
 __STRING_INLINE char *
diff --git a/string/strpbrk.c b/string/strpbrk.c
index fddd473..1ede719 100644
--- a/string/strpbrk.c
+++ b/string/strpbrk.c
@@ -27,15 +27,7 @@
 char *
 STRPBRK (const char *s, const char *accept)
 {
-  while (*s != '\0')
-    {
-      const char *a = accept;
-      while (*a != '\0')
-	if (*a++ == *s)
-	  return (char *) s;
-      ++s;
-    }
-
-  return NULL;
+  s += strcspn (s, accept);
+  return *s ? (char *)s : NULL;
 }
 libc_hidden_builtin_def (strpbrk)
-- 
1.9.1