[Bug regression/43459] New: Invalid "may be used uninitialized in this function" warning with -Os

[rwahl at gmx dot de]

Simple testcase:

--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--

#include <errno.h>
#include <unistd.h>

int testfunc(void)
{
    int ret;

    while (1) {
        const unsigned int MY_BUF_SIZE = 20;
        char buf[MY_BUF_SIZE];

        if (read(0, buf, sizeof(buf)) < 0) {
            ret = errno;
            goto bail;
        }

    }

 bail:
    return ret;
}

--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--

With gcc 4.4.3 I get:

$ gcc -Wextra -Wall -Os -c test.c 
test.c: In function ‘testfunc’:
test.c:6: warning: ‘ret’ may be used uninitialized in this function
$ gcc -Wextra -Wall -c test.c 
$ gcc -Wextra -Wall -O -c test.c 
$ gcc -Wextra -Wall -O2 -c test.c 

gcc 4.3.2 did not show this issue.


-- 
           Summary: Invalid "may be used uninitialized in this function"
                    warning with -Os
           Product: gcc
           Version: 4.4.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: regression
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rwahl at gmx dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43459