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fnmatch: work around GCC compiler warning bug with uninit var 

* posix/fnmatch_loop.c (FCT): Use a scalar not a one-item array.
This works around a bug with x86-64 GCC 4.9.2 and earlier
where 'gcc -O2 -Wmaybe-uninitialized' incorrectly complains
"../locale/weightwc.h:93:7: warning: '*((void *)&str+4)' may be
used uninitialized in this function [-Wmaybe-uninitialized]".
This commit is contained in:
Paul Eggert 2014-11-25 14:12:48 -08:00
parent bde2667a22
commit b1eda10e17
2 changed files with 18 additions and 4 deletions
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9
ChangeLog
View File

@ -1,3 +1,12 @@
2014-11-25 Paul Eggert <eggert@cs.ucla.edu>
fnmatch: work around GCC compiler warning bug with uninit var
* posix/fnmatch_loop.c (FCT): Use a scalar not a one-item array.
This works around a bug with x86-64 GCC 4.9.2 and earlier
where 'gcc -O2 -Wmaybe-uninitialized' incorrectly complains
"../locale/weightwc.h:93:7: warning: '*((void *)&str+4)' may be
used uninitialized in this function [-Wmaybe-uninitialized]".
2014-11-25 Joseph Myers <joseph@codesourcery.com> 2014-11-25 Joseph Myers <joseph@codesourcery.com>
* posix/bug-regex31.c (main): Return RES not 0. * posix/bug-regex31.c (main): Return RES not 0.

13
posix/fnmatch_loop.c
View File

@ -343,7 +343,12 @@ FCT (pattern, string, string_end, no_leading_period, flags, ends, alloca_used)
#ifdef _LIBC #ifdef _LIBC
else if (c == L('[') && *p == L('=')) else if (c == L('[') && *p == L('='))
{ {
UCHAR str[1]; /* It's important that STR be a scalar variable rather
than a one-element array, because GCC (at least 4.9.2
-O2 on x86-64) can be confused by the array and
diagnose a "used initialized" in a dead branch in the
findidx function. */
UCHAR str;
uint32_t nrules = uint32_t nrules =
_NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES); _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
const CHAR *startp = p; const CHAR *startp = p;
@ -355,7 +360,7 @@ FCT (pattern, string, string_end, no_leading_period, flags, ends, alloca_used)
c = L('['); c = L('[');
goto normal_bracket; goto normal_bracket;
} }
str[0] = c; str = c;
c = *++p; c = *++p;
if (c != L('=') || p[1] != L(']')) if (c != L('=') || p[1] != L(']'))
@ -368,7 +373,7 @@ FCT (pattern, string, string_end, no_leading_period, flags, ends, alloca_used)
if (nrules == 0) if (nrules == 0)
{ {
if ((UCHAR) *n == str[0]) if ((UCHAR) *n == str)
goto matched; goto matched;
} }
else else
@ -383,7 +388,7 @@ FCT (pattern, string, string_end, no_leading_period, flags, ends, alloca_used)
# endif # endif
const int32_t *indirect; const int32_t *indirect;
int32_t idx; int32_t idx;
const UCHAR *cp = (const UCHAR *) str; const UCHAR *cp = (const UCHAR *) &str;
# if WIDE_CHAR_VERSION # if WIDE_CHAR_VERSION
table = (const int32_t *) table = (const int32_t *)