http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56574
Bug #: 56574
Summary: False possibly uninitialized variable warning
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: mark.d.rus...@intel.com
The following code produces the warning,'value' may be used uninitialized:
int get_value(void);
void show_problem(int flag)
{
int value;
if (!flag)
value = get_value();
for (;;) {
if (!flag && value)
continue;
if (!flag)
break;
}
}
The warning occurs only with -O1 and -O2 optimization. -O0 and -O3 and higher
do not. It also occurs with many versions. I have gotten the same result with
the following versions of gcc:
i686-apple-darwin10-gcc-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5664)
gcc (SUSE Linux) 4.3.4 [gcc-4_3-branch revision 152973]
gcc (GCC) 4.4.6 20110731 (Red Hat 4.4.6-3)
gcc (GCC) 4.7.0 20120507 (Red Hat 4.7.0-5)
Interestingly, the much larger function that originally displayed the problem
does not generate a warning with the 4.7.0 compiler, but does on the others.
