http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48814
Nick Maclaren <nmm1 at cam dot ac.uk> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |nmm1 at cam dot ac.uk --- Comment #15 from Nick Maclaren <nmm1 at cam dot ac.uk> 2013-03-15 23:20:56 UTC --- I must correct some of the statements here. This is not a bug, and the intent of WG14 during the standardisation of C90 was that this should be undefined behaviour. This point was raised explicitly - unfortunately, those of us who wanted this area to be better specified did not prevail:-( This is a CHANGE in the C language introduced by C 2011. gcc may wish to adopt that, but that is not the same as saying this is a bug. As it merely degrades optimisation and does not break any working programs, it is not a major matter. The only reason that I am posting this after the decision has been taken is that there are other changes introduced by C11 that may not be so benign. There are many less than in C99, but still quite a lot. This should not be used as precedent.