long long / long long

[Bernd Schmidt]

On Sun, 9 Sep 2001, Joe Buck wrote:

> Frank Klemm writes:
> [ improved long long code sequences]
> >
> > Interested? Or are 64 bit are uninteresting for benchmarks?
>
> Well, the Linux kernel developers found that they couldn't let gcc
> do long long arithmetic because it did such a poor job, so they do
> it in assembly or in C on pairs of 32 bit values instead.  So at
> least some folks probably wouldn't mind seeing an improvement.

The main problem probably is the register allocator's requirement that
DImode values be allocated to adjacent registers.  Unfortunately this
is not going to be easy to change.


Bernd