[Bug tree-optimization/53128] [4.8 Regression] Compiler produces infinite loop on regular O2

[amonakov at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53128

Alexander Monakov <amonakov at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
                 CC|                            |amonakov at gcc dot
                   |                            |gnu.org, rguenth at gcc dot
                   |                            |gnu.org
         Resolution|                            |INVALID

--- Comment #2 from Alexander Monakov <amonakov at gcc dot gnu.org> 2012-04-26 16:20:39 UTC ---
The code invokes undefined behavior as the increment statement of the outer
loop tries to access ss[tt].a1[14] at the last iteration.  GCC optimizes out
the loop exit test due to recent changes by Richard Guenther.

Richard, I think a warning here would be very helpful (I remember you mentioned
that in IRC too).  What would implementing such a warning involve?