RFC: subreg fixing (extract_bit_field or simplify_subreg)

[Ulrich Weigand]

Aldy Hernandez wrote:

>...this creates invalid rtl: (subreg:SI (reg:DF 118) 4).

Is 118 a hard reg on your machine? If so, I've just checked
in a patch that does exactly this:

>Would it be ok to modify simplify_gen_subreg to return NULL_RTX for
>class incompatabilities [...]

See:
http://gcc.gnu.org/ml/gcc-patches/2004-10/msg02342.html


If 118 is a pseudo, I don't see why the RTL would be invalid
(reload could allocate the pseudo to a general purpose register).

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  weigand@informatik.uni-erlangen.de