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Re: Simplify floating point conversions II


> Jan Hubicka <jh@suse.cz> writes:
> 
> | > On Wed, Nov 06, 2002 at 06:54:41PM +0100, Jan Hubicka wrote:
> | > > +      For fast math it would be safe probably to convert (float)sqrt(x)
> | > > +      into sqrt((float)x), but in strict mode the argument can overflow.  */
> | > 
> | > I don't believe this to be true.
> | 
> | What you don't believe?
> 
> Likew RTH, I, skeptical that your assertion is right.
> 
> | That in ffast-math we can do the transformation?
> 
> Do we really need to do that transformation?  That is is there any
> real evidence that it brings any real benefit?
> I would be reluctant to include it even in -funsafe-math.
I am not implementing that transformation, so I am not sure.
Doing the cases I do right now and I believe to be safe brings quite
considerable amount of matches in standard C 3d graphics code that does
a lot of float and some casts to double coming from implicit C stuff.

Honza
> 
> -- Gaby


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