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Remove the str(n)cmp inlines from string/bits/string2.h. The strncmp

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optimization seems unlikely to ever be useful, but if it occurs in
real code it should be added to GCC.  Expanding strcmp of small strings
does appear useful (benchmarking shows it is 2-3x faster), so this would
be useful to implement in GCC (PR 78809).

	* string/bits/string2.h (strcmp): Remove define.
	(__strcmp_cg): Likewise.
	(strncmp): Likewise.
This commit is contained in:
Wilco Dijkstra 2017-02-15 15:23:52 +00:00
parent 3172b27b2b
commit f7db120f67
2 changed files with 6 additions and 58 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
2017-02-15 Wilco Dijkstra <wdijkstr@arm.com>
* string/bits/string2.h (strcmp): Remove define.
(__strcmp_cg): Likewise.
(strncmp): Likewise.
2017-02-15 Wilco Dijkstra <wdijkstr@arm.com>
* include/string.h: Add __cplusplus check.

58
string/bits/string2.h
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@ -92,64 +92,6 @@
#endif
/* Compare characters of S1 and S2. */
#ifndef _HAVE_STRING_ARCH_strcmp
# define strcmp(s1, s2) \
__extension__ \
({ size_t __s1_len, __s2_len; \
(__builtin_constant_p (s1) && __builtin_constant_p (s2) \
&& (__s1_len = strlen (s1), __s2_len = strlen (s2), \
(!__string2_1bptr_p (s1) || __s1_len >= 4) \
&& (!__string2_1bptr_p (s2) || __s2_len >= 4)) \
? __builtin_strcmp (s1, s2) \
: (__builtin_constant_p (s1) && __string2_1bptr_p (s1) \
&& (__s1_len = strlen (s1), __s1_len < 4) \
? (__builtin_constant_p (s2) && __string2_1bptr_p (s2) \
? __builtin_strcmp (s1, s2) \
: __strcmp_cg (s1, s2, __s1_len)) \
: (__builtin_constant_p (s2) && __string2_1bptr_p (s2) \
&& (__s2_len = strlen (s2), __s2_len < 4) \
? (__builtin_constant_p (s1) && __string2_1bptr_p (s1) \
? __builtin_strcmp (s1, s2) \
: -__strcmp_cg (s2, s1, __s2_len)) \
: __builtin_strcmp (s1, s2)))); })
# define __strcmp_cg(s1, s2, l1) \
(__extension__ ({ const unsigned char *__s2 = \
(const unsigned char *) (const char *) (s2); \
int __result = \
(((const unsigned char *) (const char *) (s1))[0] \
- __s2[0]); \
if (l1 > 0 && __result == 0) \
{ \
__result = (((const unsigned char *) \
(const char *) (s1))[1] - __s2[1]); \
if (l1 > 1 && __result == 0) \
{ \
__result = (((const unsigned char *) \
(const char *) (s1))[2] - __s2[2]); \
if (l1 > 2 && __result == 0) \
__result = (((const unsigned char *) \
(const char *) (s1))[3] \
- __s2[3]); \
} \
} \
__result; }))
#endif
/* Compare N characters of S1 and S2. */
#ifndef _HAVE_STRING_ARCH_strncmp
# define strncmp(s1, s2, n) \
(__extension__ (__builtin_constant_p (n) \
&& ((__builtin_constant_p (s1) \
&& strlen (s1) < ((size_t) (n))) \
|| (__builtin_constant_p (s2) \
&& strlen (s2) < ((size_t) (n)))) \
? strcmp (s1, s2) : strncmp (s1, s2, n)))
#endif
/* Return the length of the initial segment of S which
consists entirely of characters not in REJECT. */
#ifndef _HAVE_STRING_ARCH_strcspn