[RFC PATCH]: Reciprocal sqrt (rsqrt) conversion pass

[Richard Guenther]

On Wed, 13 Jun 2007, Uros Bizjak wrote:

> On 6/13/07, Uros Bizjak <ubizjak@gmail.com> wrote:
> 
> > I have checked some performance figures (gas_dyn.f90):
> >
> > unpatched gcc: 21.317s
> > patched gcc: 4.352s (four seconds and some).
> 
> Oh, it is an early exit in action (didn't look at the end of results):
> 
> NEGATIVE ENERGY IN CELL   201 I=-3.07200E+04 FEL= 3.33901E-07 FER= 3.31971E-07
> 
> But anyway, the caclulation goes _much_ faster.

Heh - that's easy with a wrong result ;)

Richard.