s-parallel cleanup, better error messages for rtl evaluation

[Doug Evans]

Hi.

fyi, I just checked this in.
[tested with m32r sim, all sid sims, all opcodes ports, no
changes in output]

It fixes code generation for parallels (e.g. `if' inside parallel
is now supported) by doing a proper traversal of the rtx.
[I don't think this is the final word though.
But in normal form I'm approaching this incrementally,
I certainly haven't made things worse.]

It also improves the error message during, for example, c code
generation by including the pretty-printed outer expression.
[It's not finished though, xops aren't printed in a user-friendly form.
That'll come in a later patch.]

2009-09-25  Doug Evans  <dje@sebabeach.org>

	* operand.scm (/anyof-merge-setter): Handle set-quiet.
	* rtl.scm (rtx-single-set?): Handle set-quiet.

	* rtl-c.scm (estate-make-for-rtl-c): Delete args context, owner,
	rtl-cover-fns?, macro?.  All callers updated.
	(estate-make-for-normal-rtl-c): Delete, have all callers call
	estate-make-for-rtl-c directly.
	(rtl-c-parsed): Pass #:outer-expr to estate-make-for-rtl-c.
	(rtl-c, rtl-c-expr-parsed, rtl-c-expr, rtl-c++-parsed, rtl-c++): Ditto.

	* rtl-c.scm (/par-replace-set-dest-expr-fn): New function,
	replaces /par-replace-set-dests.
	(/par-replace-set-src-expr-fn): New function, replaces
	/par-replace-set-srcs.
	(s-parallel): Rewrite.

	* rtl.scm (rtx-pretty-strdump): New function.
	* rtl-traverse.scm (/rtx-canon-error): Use it.
	(<eval-state>): New member outer-expr.
	(estate-error): Include outer expression in error message if present.