This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: AVR: CC0 to CCmode conversion
- From: Paul Schlie <schlie at comcast dot net>
- To: Denis Chertykov <denisc at overta dot ru>
- Cc: <gcc at gcc dot gnu dot org>
- Date: Fri, 18 Mar 2005 11:56:08 -0500
- Subject: Re: AVR: CC0 to CCmode conversion
> Denis wrote:
> I have converted the AVR port from CC0 to CCmode.
> But may be I have converted the port in wrong way.
> (It's because I was interested in *this* way.)
>
> I have used CCmode register and havn't added the
> '(clobber (reg:QI CC_REGNUM))' to any insn that really clobber the
> CC_REGNUM just because AVR is'n needed in scheduling.
> I think that sequence of compare + cond-jump will exists in any
> compiler pass.
> The port was successfully tested without new regressions.
> What do you (MAINTAINERS) think about this ?
Interesting:
- might you be able to post the resulting port files for review?
- are you proposing that all conditional branches then required to be
explicitly paired with a corresponding immediately previous compare
instruction?
(if so, how is this a good thing observing that it's fairly typical
for most conditional branches to be naturally based on comparisons
against 0 resulting from the immediately preceding operation, which
would have otherwise not required an explicit compare?)
thanks