Re: FWD: FLOATING-POINT CONSISTENCY, -FFLOAT-STORE, AND X86

[Emil Hallin <emil at skatter dot usask dot ca>]

I have been following this thread with a great deal of interest. I very much
appreciate your proposal AND I endorse it completely. I am more than willing to
pay a performance penalty in order to get numerically accurate results with less
programming on my part. Also, I am not willing to use a tool which *deliberately*
produces incorrect code, when the right thing to do is both known and can be
implemented in a reasonable way. With the increasing pervasiveness of computers in
every area of life, and with the increasing use of linux, it is not a huge stretch
of the imagination to believe that at some point in the future people's lives
might depend on a piece of gcc/g77 compiled code that made the wrong decision
because of a numerical error! And yes, the code in question *might* have been
written (and tested) by someone who would simply not be aware of the possibility
that a test based on a < b would not *always* be evaluated the same way.

Craig, please don't give up. Faster CPUs are always available for those that need
the ultimate speed.

And for those who need the ultimate performance, even if this proposal were to
reduce speeds by 25%, your CPU today is an order of magnitude faster than it was a
year or so ago.
    emil