[m-dev.] 32-bit sources on 64-bit target

[Julien Fischer]

Hi Peter,

On Fri, Mar 8, 2013 at 10:51 AM, Peter Wang <novalazy at gmail.com> wrote:
> On Fri, 8 Mar 2013 00:38:58 +1100, Julien Fischer <jfischer at opturion.com> wrote:
>> On Fri, Mar 8, 2013 at 12:17 AM, Paul Bone <paul at bone.id.au> wrote:
>> > On Thu, Mar 07, 2013 at 06:00:24PM +1100, Julien Fischer wrote:
>> >> On Thu, Mar 7, 2013 at 5:08 PM, Peter Wang <novalazy at gmail.com> wrote:
>> >> > The compiler built from pre-generated sources WILL be installed.
>> >> > For now, I can't think of why that would be a problem.
>> >>
>> >> It wouldn't be at the moment since the compiler (and other tools)
>> >> are currently built with --mercury-linkage static.  It would be a problem,
>> >> if that were not the case.
>> >>
>> >
>> > How much of a performance gain does unboxed floats and 3 tag bits represent
>> > specifically for the compiler?
>
> Suprisingly, significant: (default speedtest)
>
> mercury_compile.01 average of 6 with ignore=1     10.00
> mercury_compile.02 average of 6 with ignore=1     12.08

That's quite a difference.  Is mercury_compile.02 built directly from
the source distribution
C files.   The source distribution C files are also built with
--no-smart-indexing,  so that
may also be having an affect.   For the record recent source
distributions are built with:

    -O5 --opt-space --cross-compiling --no-smart-indexing

> Tell me again why we aren't providing 64-bit sources already?

We do provide 64-bit sources (in Mercury!).

Providing 64-bit source distributions isn't really going to reduce the
complexity
of building Mercury from scratch, just shift it around a bit.   (I
don't have any
objection to them per se, so if people feel this is the right way to
go, that's fine
by me.)

Cheers,
Julien.