value range propagation for _bitwise_ OR

[Adam D. Ruppe]

On Sat, Apr 10, 2010 at 08:42:54PM -0500, Andrei Alexandrescu wrote:
> What results does it yield with my main() test harness?

total=100000000; equal=14585400 (14.5854%)

I think that's a perfect result. Here's why: the equality comparison checks
two specific values, (a, b), but the maxOr functions return the max for the
interval ([0, a], [0, b]). It wouldn't always be equal, since there are other
values in there that can reach the max.

For example, a = 4, b = 4. 100|100 == 100, but that range also include 4|3,
100 | 011 == 111, which is the max.


Your maxOR function gives the same percentage, for probably the same reason.
Though, mine runs ~7x faster on my box.

-- 
Adam D. Ruppe
http://arsdnet.net