[Bug target/92729] [avr] Convert the backend to MODE_CC so it can be kept in future releases

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92729

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |burnus at gcc dot gnu.org

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> ---
(In reply to John Paul Adrian Glaubitz from comment #0)
> We have already successfully funded such a conversion for the m68k backend,
> see #91851.
PR 91851.

avr bounty page:
https://www.bountysource.com/issues/84630749-avr-convert-the-backend-to-mode_cc-so-it-can-be-kept-in-future-releases

Regarding the deprecation, see
  https://gcc.gnu.org/ml/gcc-patches/2019-09/msg01256.html
and the follow up remark regarding the deprecation at
  https://gcc.gnu.org/ml/gcc-patches/2020-01/msg01773.html


[BTW: cris is being converted in the GIT branch vendors/axis/cris-decc0,
scheduled for GCC 11 Stage 1. m68k has been converted and is in GCC 10. h8300,
cr16 and vax are still deprecated. For h8300, see also
https://gcc.gnu.org/ml/gcc-patches/2019-10/msg02068.html]

[Side remark: once MODE_CC is used, at some point the register allocator should
also be changed from 'reload' to LRA, cf. https://gcc.gnu.org/wiki/LRAIsDefault
; for now, only CC0 was suggested to be deprecated in GCC 10 and scheduled for
removal in GCC 11.]