------- Comment #25 from steven at gcc dot gnu dot org 2010-01-30 23:19 ------- It should be consistent for programs that do not trigger undefined behavior. The behavior of your program is undefined according to the C standard and according to GCC.
The alias discussion is just one of th many where different crowds are asking for different semantics for undefined behavior. But the point of "undefined" is that, well, the behavior is undefined. So, although it is counterintuitive (and in fact, quite unfriendly of the compiler) it is not incorrect to have different program behavior at different optimization levels for a program with undefined behavior. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42907
