This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/23855] loop header should also be pulled out of the inner loop too
- From: "dberlin at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 24 Oct 2006 14:23:35 -0000
- Subject: [Bug tree-optimization/23855] loop header should also be pulled out of the inner loop too
- References: <bug-23855-10053@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #22 from dberlin at gcc dot gnu dot org 2006-10-24 14:23 -------
(In reply to comment #19)
> So it is indeed chicken and egg ;) load-PRE does not PRE the loads if the loop
> is not in do-while form, and we won't hoist the loop header copies until the
> loads are PREd. As to comment #13, if we are able to "clean" the two innermost
> loops
> of a nest that is already a good improvement. Though from all the experiments
> it looks like it is advisable to write do-while loops with hoisted loop header
> copies manually rather than for loops.
>
So the PRE fixes i've got should help here, i think.
Maybe not.
:)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23855