[Bug target/51002] SP_H register is used even on targets that do not have it (eg attiny26)

[wiml at hhhh dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51002

--- Comment #2 from Wim Lewis <wiml at hhhh dot org> 2011-11-26 21:02:55 UTC ---
I think that would produce correct code, at least.

It seems like it would be more efficient for gcc to treat the stack pointer as
mode QI on these parts, and promote it to HI when it needs to use it as a
general purpose pointer; there's no reason to allocate r29 since it will always
contain 0. But that might not be the minimal bugfix.