http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55009
--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2012-10-21 23:41:28 UTC --- The C standard requirements that certain source code has certain semantics (such as, in this case, overflows making something not an integer constant expression and so an array a VLA) are unchanged by -fwrapv; that simply concerns what happens for certain code that under standard C would be undefined at runtime. The diagnostic is correct and probably occurs as a result of fixes for various internal compiler errors relating to expressions with integer operands that are not integer constant expressions. However, it might be possible to downgrade it to a pedwarn the way it is already downgraded for some other expressions folding to an integer constant.
