[Bug c++/89192] -Wuninitialized doesn't warn about a vector initialization with uninitialized field

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89192

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
             Blocks|                            |24639

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
It works with optimization:

> g++-8 t.C -Wuninitialized -Wmaybe-uninitialized -O
t.C: In function ‘int main()’:
t.C:7:34: warning: ‘m.MyStruct::b’ is used uninitialized in this function
[-Wuninitialized]
     MyStruct(unsigned arg1): vec(b), b(arg1){}
                                  ^

the reason is that at -O0 all calls such as the constructor are left in place
and thus the uninitialized use is not exposed to function-local analysis.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24639
[Bug 24639] [meta-bug] bug to track all Wuninitialized issues