[RFC,PATCH] combine: Don't simplify subregs of promoted types

[Ian Lance Taylor]

Andreas Krebbel <Andreas.Krebbel@de.ibm.com> writes:

> I'm experimenting with a patch which introduces a combine_simplify_subreg 
> function.  That function records the promotion information in reg_stat when a subreg
> is optimized away.  This makes the ZERO_EXTEND to be removed in
> expand_compound_operation.  I'm currently trying to enhance this in order to 
> cover SIGN_EXTENDS as well using the sign_bit_copies field.  Does that sound like
> a solution to you?

Yes, that sounds promising.  Thanks.

Ian