C++ ABI and ILP64

[Joe Buck]

On Thu, Dec 16, 2004 at 02:02:51AM +0100, Markus F.X.J. Oberhumer wrote:

> I'm currently playing around making and testing an experimental port of
> AMD64 for the ILP64 programming model ...

> In case you're wondering, we're working on very high speed data compression 
> libraries, and apart from being useful for portability testing (e.g. for 
> those old Cray machines) ILP64 also seems to generate a little bit better 
> code for our purposes, mainly because a number of implicit unsigned char -> 
> int -> size_t promotions within complex expressions can be shortened to char 
> -> size_t, so this is not purely academic.

If the code you get for I32, LP64 is really worse because of this issue
(inefficient conversions), that seems broken, and fixing such bugs seems
more worthwile than trying to make a complete ILP64 port just to work
around them.