Minor reload cleanup

[Jeffrey A Law]

  In message < Pine.LNX.4.10.9910171035350.3329-100000@biriani.cygnus.co.uk >you 
write:
  > > I extracted this from Bernd's recent patch.  There's no reason not to go
  > > ahead and get reload_mode & reload_nregs moved into struct reload.
  > 
  > There are more parts in that patch and some other cleanups that can be
  > broken out and installed first.
  > (In case you are wondering, the save_xxx variables were storing mostly
  > zeroes, and their contents can be restored by bzero and the walk of the
  > existing reg_rtx values).
  > 
  > A patch I had yesterday that included this and the part you already
  > installed bootstrapped on i386.
  > 
  > Bernd
  > 
  > 	* reload.h (struct reload): Fix definition of mode elt.
  > 	* reload.c (find_reloads): Compute mode and nregs fields of all
  > 	reloads.
  > 	* reload1.c (calculate_needs_all_insns): Simplify a bit.
  > 	(calculate_needs): Use precomputed mode/nregs values.
  > 	(allocate_reload_reg): Likewise.
  > 	Break out two...
  > 	(failed_reload, set_reload_reg): ... new functions.
  > 	(choose_reload_regs_init): New function, mostly broken out from...
  > 	(choose_reload_regs): ... here.  Lose all the save_xxx nonsense.
  > 	Also lose one #if 0 block.
This is fine.  Please install it.

Note the reload.h change probably won't apply since I fixed the horrible
goof of mine the night I mucked it up.

jeff