http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56928
Bug #: 56928
Summary: false positive when using -Wstrict-overflow
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: vap...@gentoo.org
Target: x86_64-linux-gnu
i've got some code that is triggering a warning when using gcc-4.8.0 and -O2
with -Wstrict-overflow. pretty sure the warning is wrong -- when i tweak the
code slightly (in unrelated ways), it goes away.
playing with older versions shows that 4.[234].x work, but 4.[5678].x fail
the reduced test case:
$ cat test.i
struct stat {
int st_mode;
};
const char *foo(char c, int x, struct stat s)
{
int i;
char dynamic = 0;
if (c == 1)
for (i = 0; i < x; i++)
dynamic = 1;
if (!dynamic || !(s.st_mode & 1))
return dynamic ? "d" : "!d";
}
$ gcc -O2 -c test.i -Wstrict-overflow
test.i: In function ‘foo’:
test.i:12:24: warning: assuming signed overflow does not occur when simplifying
conditional to constant [-Wstrict-overflow]
return dynamic ? "d" : "!d";
^
