This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: GCC Status Report (2004-03-09)
>>>>> "Zack" == Zack Weinberg <zack@codesourcery.com> writes:
Zack> Ian Lance Taylor <ian@wasabisystems.com> writes:
>> Paul Koning <pkoning@equallogic.com> writes:
>>> Perhaps we need asm("":::"barrier")?
>> Seconded. For high performance device manipulation, it would be
>> good to have a way to say "do not schedule instructions across
>> this point" without also saying "clobber everything".
Zack> __builtin_fence() (possibly with an argument to request various
Zack> sorts of memory barriers that various architectures have) seems
Zack> preferable to me over asm()...
Good point. You'd want to be able to ask for memory barrier
instructions, or not -- in some cases all you need is to block
scheduler actions, and the ordering rules of the target machine are
otherwise sufficient for the purpose.
paul