[Patch, AVR]: Fix PR46779

[Georg-Johann Lay]

Do you think we can split the patch intended to fix PR46779

> 	PR target/46779
> 	* config/avr/avr.c (avr_hard_regno_mode_ok): Rewrite.
> 	In particular, allow 8-bit values in r28 and r29.
> 	(avr_hard_regno_scratch_ok): Disallow any register that might be
> 	part of the frame pointer.
> 	(avr_hard_regno_rename_ok): Same.

http://gcc.gnu.org/ml/gcc-patches/2011-06/msg00810.html

from the other work discussed in this thread that aims at fixing
PR45291 which is "just" an optimization issue because of fake X
addressing?

These PR are two different things.

Johann