[Bug tree-optimization/86223] missing -Warray-bounds on an access to an implicitly zeroed out array

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86223

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-06-21
                 CC|                            |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
We gimplify g to

      a = {};
      _2 = a[i];

but h to

      a[0] = 0;
      a[1] = 0;
      a[2] = 0;
      _2 = a[i];

that is IMHO a missed optimization.  With the g IL we fold a[i] to zero
while with the h IL we do not (that's somewhat inconsistent I agree).

If you do

  int a[3] = { 1 };

you get the desired warning.