[m-dev.] for review: --optimize-mostly-det-tailcalls

[Thomas Conway]

On Sun, Jun 06, 1999 at 01:14:41PM EST, Zoltan Somogyi wrote:
> +code_info__may_use_nondet_tailcall(NoCheckTailCall, CheckTailCall) -->
>  	code_info__get_fail_info(FailInfo),
> -	{ FailInfo = fail_info(ResumePoints, ResumeKnown, _, _, _) },
> -	(
> -		{ ResumeKnown = resume_point_known },
> -		{ stack__top_det(ResumePoints, TopResumePoint) },
> -		{ TopResumePoint = stack_only(_, do_fail) }
> +	{ FailInfo = fail_info(ResumePoints0, ResumeKnown, _, _, _) },
> +	{
> +		stack__pop(ResumePoints0, ResumePoint1, ResumePoints1),
> +		stack__is_empty(ResumePoints1),
> +		ResumePoint1 = stack_only(_, do_fail)
>  	->
> -		{ MayTailCall = yes }
> +		(
> +			ResumeKnown = resume_point_known,
> +			NoCheckTailCall = yes,
> +			CheckTailCall = no
> +		;
> +			ResumeKnown = resume_point_unknown,
> +			NoCheckTailCall = no,
> +			CheckTailCall = yes
> +		)
>  	;
> -		{ MayTailCall = no }
> -	).
> +		NoCheckTailCall = no,
> +		CheckTailCall = no
> +	}.

These variable names are very confusing, since NoCheckTailCall sounds
very much like it should be the negation of CheckTailCall. Using an
enumeration or two rather than bools would help.

Apart from this issue, this change looks okay.

-- 
 Thomas Conway  )O+  |   Master, I go hunting.
     Mercurian       |     -- Le Guin, A Wizard of Earthsea
<conway at cs.mu.oz.au> |
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