SMALL_REGISTER_CLASSES

[Jeffrey A Law]

  In message < 199801260508.QAA01591@discus.anu.edu.au >you write:
  > Unfortunately, the user can mention regs explicitly in 'asm'
  > statements, too.  This causes problems on rs6000, where there are
  > no small register classes mentioned in the RTL, but users can write
  > things like
  > 
  > asm ("" : : : "cr0");
  > 
  > and get 'forbidden register spilled' if a pseudo (in this case, most
  > likely derived from a "CC" in the RTL) needs a register of that class.
This is a separate and distinct problem from whether or not a machine
description should mention registers explicitly in RTL.

Jeff