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Re: [cxx-conversion] Make double_int a class with methods and operators. (issue6443093)


On Wed, Aug 8, 2012 at 9:09 AM, Miles Bader <miles@gnu.org> wrote:
> Mike Stump <mikestump@comcast.net> writes:
>>> Constructors are allowed, but PODs are often passed more efficiently.
>>> That property seemed particularly important for double_int.
>>
>> Show us the difference in timing.  Show us the generated code.  I
>> can't imagine that it could ever matter.
>
> I'm also curious about that statement...  PODs don't really seem to
> offer much advantage with modern compilers, except in a few very
> specific cases (of which this doesn't seem to be one), e.g. in unions.

They make a difference for the by-value passing ABI.  double-ints can
be passed in two registers on most platforms.

Richard.

> -miles
>
> --
> values of β will give rise to dom!


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