[Bug c/82206] New: -Wformat-nonliteral does not warn when passing a non literal to vprintf

[simon.marchi at polymtl dot ca]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82206

            Bug ID: 82206
           Summary: -Wformat-nonliteral does not warn when passing a non
                    literal to vprintf
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: simon.marchi at polymtl dot ca
  Target Milestone: ---

Created attachment 42165
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42165&action=edit
Reproducer

I have extracted this small snippet (see attached file) from the
microblaze-tdep.c source file in GDB.  clang gives this warning when passing a
non literal to vprintf:

$ clang-4.0 test.c -Wformat -Wformat-nonliteral
test.c:10:12: warning: format string is not a string literal
[-Wformat-nonliteral]
  vprintf (fmt, args);
           ^~~
1 warning generated.


gcc 7.2 with the same arguments does not emit any warning.  Would it make sense
for gcc to also emit it?