regclass.c: scan_one_insn special casing

[David Edelsohn]

>>>>> Michael Matz writes:

Michael> If anything the place of that code seems to be a bit strange, at least
Michael> from current perspective.  After these many years we might have a better
Michael> place.  OTOH it has to examine the insn constraints and the earliest point
Michael> GCC is doing this is in regclass.  Clearly it would be even better if
Michael> reload wouldn't do the stupid thing which this code is supposed to help.

	This discussion thread appears to be mixing two issues: the code
appearing in a common part of the compiler and these types of special
cases scattered around the compiler.  The diffusion of this type of code
is a maintenance problem, but a single implementation should be a
benefit.

	If we could collect this type of functionality in an efficient
implementation in a central, well-defined location, GCC would be better.

David