[Bug c/65244] New: Bogus -Wmaybe-uninitialized warning with posix_memalign() and -Og

[ulfalizer at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65244

            Bug ID: 65244
           Summary: Bogus -Wmaybe-uninitialized warning with
                    posix_memalign() and -Og
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ulfalizer at gmail dot com

The warning

  posix_memalign_warn.c: In function ‘f’:
  posix_memalign_warn.c:9:5: warning: ‘ptr’ may be used uninitialized in this
function [-Wmaybe-uninitialized]
       return ptr;
       ^

is generated when compiling the following with

  gcc -Og -Wmaybe-uninitialized -c posix_memalign_warn.c

No warning is produced for -O0/1/2/3/fast.


#include <stdlib.h>

void *f(void) {
    void *ptr;

    if (posix_memalign(&ptr, 16, 256) != 0)
        exit(EXIT_FAILURE);

    return ptr;
}