Re: Optimization flag for unchecked fixnums in SBCL?

Jeff Barnett <jbb@notatt.com> writes:

As a start, did you you try defining collatz and clen with defsubst?
Did you try using declarations and their cousins? And did your CL
system provide a decent, declaration-sensitive compiler?

I didn't try defsubst.  I did try some declarations but didn't get them
to work.  I think that means I didn't use them properly, rather than
that they don't work.  Yes, SBCL is a serious optimizing compiler.  If
not the premier compiler, it is one of them.

Other than use defsubst. That should open code most anything in most
any CL compiler-based system.

I think the issue is not funcall overhead, but rather, the slowness of
bignum arithmetic compared to just hoping that everything fits in a
fixnum.  The "trick" of this Euler problem is that a few (only a few) of
the intermediate values will overflow a 32 bit word.  But, everyone uses
64 bit machines these days, so that part works anyway.