Optimisation prevents overflow?

[Steve Kargl]

On Thu, Jul 19, 2007 at 02:42:06PM -0700, Brooks Moses wrote:
> On Thu, Jul 19, 2007 at 11:35:15PM +0200, Daniel Franke wrote:
> > On Thursday 19 July 2007 23:05:06 Davide Mancusi wrote:
> > > Is optimisation preventing overflow? What is really happening here?
> > 
> > In other mail:
> > > ...and yes, -ffloat-store fixes it. What does it do? I could not find
> > > documentation about it.
> > 
> > I'd guess, that's the (in)famous extended precision, 80 vs. 64 bits (iirc). 
> 
> Yeah, I thought so at first, but those both have the same exponent range
> IIRC, and certainly not enough to get up to an erroneous answer of 273
> instead of 18 before it overflows.

Why?  His code is doing a floating comparison where one if not
both operands are outside the range of representable numbers.
The standard makes no guarantee in this instance.

-- 
Steve