http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49379
--- Comment #4 from Gary Funck <gary at intrepid dot com> 2011-06-12 13:04:59 UTC --- We think that this issue is related to an optimization that increases the alignment of common symbols that have the potential to improve vectorization. We didn't run a reghunt, but it looks like this may have been the update that initially implemented the alignment change. r120576 | hubicka | 2007-01-08 03:13:14 -0800 (Mon, 08 Jan 2007) | 23 lines [...] * tree-vectorizer.c (increase_alignment): Move here from cgraphunit.c (gate_increase_alignment): New function. (pass_ipa_increase_alignment): New pass. We've determined: (1) the vanilla GNU/Linux linker doesn't complain, (2) the installed (Apple) GCC compiler likely pre-dates the change above.