Re: Compile-time optimization of mathfn(CST) ?

[Bernd Jendrissek <berndj at prism dot co dot za>]

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On Thu, Mar 25, 2004 at 08:20:52AM -0500, Kaveh R. Ghazi wrote:
> I'm wondering whether we can safely optimize builtin mathfn(CST) into
> a compile-time value by calling the host's `mathfn' when not
> cross-compiling.
> 
> I understand that in the past it's been discussed that we need to use
> GMP's library to calculate the constant results to sufficient digits
> in the case where the target's FP has greater precision.  However I
> don't see anyone working on this yet, (including me.)
> 
> So I'm wondering if we can simply call the host math functions and
> wrap this in !CROSS_COMPILE so that we catch a vast portion of the
> cases where this transformation is useful.

So you'll produce different object code depending on whether a native or
a cross compiler produced the code?  How will the regression testers
like that?

Or maybe you can add __builtin_native_evaluate() that you can put around
__builtin_sin() that will tell GCC that you want the result evaluated
NOW (IOW compile-time).  Then you have control over native-vs-cross
inconsistencies where it belongs - in the source.

- -- 
"IBM has more patent litigation lawyers than SCO has employees." - unknown
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