On Tue, Mar 16, 2010 at 9:05 PM, Tristan Gingold <ging...@adacore.com> wrote: > > On Mar 16, 2010, at 3:50 PM, H.J. Lu wrote: > >> 2010/3/8 Paweł Sikora <pl...@agmk.net>: >>> hi, >>> >>> during development a cross platform appliacation on x86 workstation >>> i've enabled an alignemnt checking [1] to catch possible erroneous >>> code before it appears on client's sparc/arm cpu with sigbus ;) >>> >>> it works pretty fine and catches alignment violations but Jakub Jelinek >>> had told me (on glibc bugzilla) that gcc on x86 can still dereference >>> an unaligned pointer (except for vector insns). >>> i suppose it means that gcc can emit e.g. movl for access a short int >>> (or maybe others scenarios) in some cases and violates cpu alignment rules. >>> >>> so, is it possible to instruct gcc-x86 to always use suitable loads/stores >>> like on sparc/arm? >>> >>> [1] "AC" bit - http://en.wikipedia.org/wiki/FLAGS_register_(computing) >>> >> >> I am interested in an -mstrict-alignment option for x86. > > Not sure it will be useful. The libc still does unaligned accesses IIRC. > >
Wow. What for? Alexey
