[Bug c/77690] -Wformat-length %s false positive after strlen check

["msebor at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77690

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2016-09-23
                 CC|                            |msebor at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |msebor at gcc dot gnu.org
     Ever confirmed|0                           |1
      Known to fail|                            |7.0

--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Unfortunately, even though it seems like the if statement with the strlen call
should help, the length range information isn't available to the warning pass. 
The warning can, however, be avoided by constraining the length of the string
argument output by specifying the precision in the directive like so:

  sprintf(foo, "zz%.4s", s.buf);

Please let me know if this isn't sufficient to resolve the problem report.