bignums and native back end
Stephen Weeks
MLton@sourcelight.com
Wed, 8 Nov 2000 16:47:53 -0800 (PST)
> I'm slightly confused how the cps phase can do this optimization. In int-inf.h
> the function InfInt_areSmall is defined (it is a primitive) which checks if
> its two arguments are both small (by anding them together with 1 and seeing if
> it is 0). Since it is in a primitive, no higher levels see this and.
> Did you just instruct the shrinker that
> IntInf_areSmall(x, small-constant) = IntInf_isSmall(x)
> and similarly for the reverse order?
Yes.
> Also just how much do the upper levels know about small things?
They know about IntInf_isSmall and IntInf_areSmall. What else were you thinking
about?
> Any way, all of this (and the re-associating so that
> x + constant + constant
> turns into `x + (constant + constant)') is very fine.
I didn't do the re-associating stuff. It doesn't fit very well into the current
shrinker.