On 11/02/2010 11:39 AM, Georg Lay wrote:
Paolo Bonzini schrieb:
On 11/02/2010 10:41 AM, Georg Lay wrote:
What I do not understand is*why* this works.
The internals "16.16 How to Split Instructions" mention two flavours
of insn
splitting: One after reload for the scheduler and one during combine
stage, the
latter just doing single_set --> 2 * single_set splits for insns that
do*not*
match during combine stage.
I think this is extremely out-of-date, I am sorry. I read something
from Ian Lance Taylor on the mailing list recently about the history of
splits. I cannot find it now, but basically the original purpose (help
combine to find matches for "big" patterns representing more than one
instruction) is now almost obsolete with define_insn_and_split, and the
split passes before and after reload have the biggest role in splitting.
You mean this?
http://gcc.gnu.org/ml/gcc/2010-10/msg00444.html
Yes, that and the follow up.
Paolo
