Call for port conversions to MD define_constraint

["Zack Weinberg" <zackw at panix dot com>]

Back in 2006 I added a mechanism for defining machine-specific
constraints in the MD file rather than with C macros. This mechanism
offers several advantages over the old way of doing it, but until all
ports are converted, we can't actually implement some of those -- most
important, perhaps, is that we could move some of the work done by
recog and reload in processing constraints to build time, once all
ports are converted.

I don't personally have time to convert all ports, and it is better if
people who know each individual  backend and have access to hardware
do the conversions, anyway.  So I'd like to invite port maintainers to
convert their ports in this development cycle.   I see that many of
the more popular CPUs have already been done:

   alpha arm avr i386 ia64 m68k mips rs6000 s390 spu xtensa

but there are still a lot left to go:

   arc bfin c4x cris crx fr30 frv h8300 iq2000 m32c m32r m68hc11 mcore mmix
   mn10300 mt pa pdp11 score sh sparc stormy16 v850 vax

If all ports are converted by, oh, the beginning of August, I'll find
time to implement the precalculation of constraint sets for reload and
recog.

zw