http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50905
--- Comment #4 from xunxun <xunxun1982 at gmail dot com> 2011-10-28 20:14:38
UTC ---
(In reply to comment #3)
> Yes if you mean without -O1/-O2/-O3 -ftree-parallelize-loops does not work,
> this is expected as explained in the manual, -O1 enables more than the options
> that includes adding more optimizations.
Thanks for the information.
-----------------------
I read the manual:
-ftree-parallelize-loops=n
Parallelize loops, i.e., split their iteration space to run in n threads.
This is only possible for loops whose iterations are independent and can be
arbitrarily reordered. The optimization is only profitable on multiprocessor
machines, for loops that are CPU-intensive, rather than constrained e.g. by
memory bandwidth. This option implies -pthread, and thus is only supported on
targets that have support for -pthread.
I don't notice any -O1/-O2/-O3 Optimization information here.
-----------------------
If the information is true, we should only deal with the issue between
-ftree-parallelize-loops=n and -ffast-math
