patch to fix constant math

[Nathan Froyd]

----- Original Message -----
> Btw, as for Richards idea of conditionally placing the length field
> in
> rtx_def looks like overkill to me.  These days we'd merely want to
> optimize for 64bit hosts, thus unconditionally adding a 32 bit
> field to rtx_def looks ok to me (you can wrap that inside a union to
> allow both descriptive names and eventual different use - see what
> I've done to tree_base)

IMHO, unconditionally adding that field isn't "optimize for 64-bit
hosts", but "gratuitously make one of the major compiler data
structures bigger on 32-bit hosts".  Not everybody can cross-compile
from a 64-bit host.  And even those people who can don't necessarily
want to.  Please try to consider what's best for all the people who
use GCC, not just the cases you happen to be working with every day.

-Nathan