What is acceptable for -ffast-math? (Was: associative law in combine)

[Theodore Papadopoulo]

Gabriel.Dos_Reis@sophia.inria.fr said:
> | and probably a whole lot of other things that are equally "dubious".
> |  |  | > But then, if they would have written that form in the first
> place. |  | But, as I said, there might be cases where you can't write
> it in an | optimized way in the first place, such as in |   inline
> double f() { return a/b; } |   inline double g() { return c;   } |   x
> = f()/g(); | plus inlining. 

> But then is 0.0 is acceptable for 0.125 for speed? 

Yes, if you know by advance that this cannot happen because of your 
input data accuracy. Then you will get the speed advantage without 
the loss of accuracy since it cannot happen.


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Theodore Papadopoulo
Email: Theodore.Papadopoulo@sophia.inria.fr Tel: (33) 04 92 38 76 01
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