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Re: Rewrite some jump.c routines to use flags


Eric Botcazou <ebotcazou@adacore.com> writes:
>> ...trapping on signalling NaNs is enough for the field to be true.
>
> So what's the point in encoding this?  The main distinction, and the only one 
> relevant for the RTL middle-end, is whether the operator traps on quiet NaNs 
> since this can change the comparison instruction emitted by the back-end.

AIUI, neither ORDERED nor UNEQ trap on signalling NaNs.  Without this,
the follow-on patch would fold

   (and (ordered x y) (uneq x y)) -> (eq x y)

which is the same thing for quiet NaNs but not for signalling NaNs.

Thanks,
Richard


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