cant_combine_insn_p hard_reg->reg moves

[Jan Hubicka]

> On Tue, Dec 25, 2001 at 09:02:42PM -0500, David Edelsohn wrote:
> > Could cant_combine_insn_p test for hard regs with either REG_EQUIV
> > involving computations of ARG_POINTER_REGNUM or FUNCTION_VALUE_REGNO_P?
> 
> No.  IIRC, this was introduced specifically to cure problems with
> argument registers.  x86 regparm is the biggest offender here.
> 
> The only solutions are a new register allocator, or post-reload
> cleanup optimizations such as -fcprop-registers.  Anything else
> risks keeping a hard register live too long.

BTW what is the situation of cprop-registers? Will it get enabled for 3.1
once the bugs are tracked down. Are the problems serisous.

Honza
> 
> 
> r~