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Re: Ada subtypes and base types


On Tue, 2006-03-21 at 17:41 +0100, Duncan Sands wrote:

> Should it be?  I was surprised to see that all ranges are initialised
> to VR_VARYING in the vrp pass, since many types have natural ranges
> associated with them, for example [0, 255] for the above unsigned char;
> starting off with this natural range is, well, natural, and surely
> simplifies a bunch of code, by making things more uniform, eg: no need
> to special case unsigned values, type conversions, ...
Depends on who you talk to -- we certainly have a problem in that we
have two ways to represent the same thing and the optimizer treats
the two representations differently.

In a world where we could handle VR_VARYING without pessimizing so
much, then I don't think either representation would be clearly
better than the other.

Jeff


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