http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52106
Bug #: 52106
Summary: missing -Wunused-but-set-variable warning with the a =
b = ... construct
Classification: Unclassified
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: vincent-...@vinc17.net
The following code
int foo (void)
{
int a, b, c, d;
a = b = 0;
c = d = 0;
return a + d;
}
gives:
$ gcc-snapshot -Wall -c tst.c
tst.c: In function 'foo':
tst.c:3:13: warning: variable 'c' set but not used [-Wunused-but-set-variable]
One would expect the same warning for variable 'b'. Even though it appears to
be used to assign variable 'a', it shouldn't count in such a construct. Indeed
a variable assignment is useless if the variable isn't used in a later
expression (if the goal is to convert the value, then a cast would be more
readable).
Tested with:
gcc (Debian 20120128-1) 4.7.0 20120128 (experimental) [trunk revision 183664]
