diff: more trailing changes

[Fergus Henderson]

Hi,

Peter Schachte, can you please review this one?

Change the generated code for trailing to match the new trailing interface.

compiler/code_gen.m:
	When generating code for negations, ensure that we generate a
	discard_ticket instruction to discard the current ticket before
	failing.

compiler/llds.m:
compiler/llds_out.m:
compiler/code_info.m:
	Change the `restore_ticket(Rval)' instruction to
	`reset_ticket(Rval, Reason)', where Reason is one of
	undo, commit, exception, or gc, as per runtime/mercury_trail.h.
	A reset with Reason = undo gives the old "restore" behaviour.

compiler/frameopt.m:
compiler/livemap.m:
compiler/llds_common.m:
compiler/middle_rec.m:
compiler/opt_*.m:
compiler/peephole.m:
compiler/value_number.m:
compiler/vn_*.m:
	Trivial changes to handle reset_ticket/2 instead of restore_ticket/1.

compiler/code_gen.m:
compiler/ite_gen.m:
compiler/disj_gen.m:
	Change the places that called code_gen__maybe_discard_ticket
	to instead call code_gen__maybe_reset_and_discard_ticket(...commit...).

-- 
Fergus Henderson <fjh at cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
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