http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56245
--- Comment #8 from Kostya Serebryany <kcc at gcc dot gnu.org> 2013-02-08 18:28:43 UTC --- Ah, so this *is* caused by the asan merge, although it's not an asan bug. The new asan allocator often returns pointers that are >4Gb apart from each other so that int is not working for pointer differences any more. BTW, I think that subtracting one pointer from another if they belong to different heap allocations is just plain wrong standard-wise.
