Draft "Unsafe fp optimizations" project description.

[dewar@gnat.com]

<<I think what Toon meant was something like: if you throw all the
possible distinct values for a given FP representation into a sack, and
pick the operands at random from the sack, there's roughly a 50/50
chance that B*C will overflow or underflow.
>>

I agree that's what he meant, but that is entirely wrong, the proportion
of numbers that overflow is far far smaller. Remember we are talking about
floating-point values here, not real values. There are as many fpt 
numbers with an exponent of 1 as there are with an exponent of 100 :-)