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Re: [PATCH] Canonical types (1/3)


Richard Kenner wrote:

> However, I'm wondering whether "narrowing" what we consider a "variant"
> really is a good idea given this change.  In some sense, TYPE_CANONICAL
> and TYPE_MAIN_VARIANT represent the same concept. 

TYPE_CANONICAL is about the language idea of "the same type".
TYPE_MAIN_VARIANT is "the cv-unqualified variant of this type, treating
typedefs as different."  So, I don't think they're really the same.

We could get rid of TYPE_MAIN_VARIANT, make TYPE_NEXT_VARIANT a circular
list, and find TYPE_MAIN_VARIANT by walking TYPE_NEXT_VARIANT until we
find a cv-unqualified type.   That would save memory, but not
necessarily time.  However, if we typically only have at most 2 variants
(unqualified and "const"), then it might be a win.

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713


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