[m-dev.] argument packing

[Julien Fischer]

On Wed, 16 May 2018, Julien Fischer wrote:

> On Tue, 15 May 2018, Zoltan Somogyi wrote:
>
>>  So if you have compiled the Mercury programs you are working on
>>  with an installed compiler which has had its default values of
>>  allow_packing_ints and allow_packing_dummies set to `yes',
>>  and had those programs pass all their tests, please tell me.
>>  If you haven't, then please do so and tell me.
>>  And if you had any failures, please tell me as well.
>
> I have tested the new options with the following:
>
>    * my JSON library [passes in asm_fast.gc]
>    * my CSV library [passes in asm_fast.gc]
>    * the Zinc compiler [passes in hlc.gc]
>    * Opturion's runtime system [passes in hlc.gc.trseg]
>    * Two of our transport optimisers
>
> At least one of the latter is now giving me different results that
> differ from a system built with rotd-2018-05-10.  They're not incorrect
> as such, just marginally different.  (There may be factors other than
> the Mercury compiler in play, I'll have to investigate further.)

I've had a further look at this, whatever the issue is it's not caused
by the new optimisation; with the current repository head I get
identical results with the optimisation disabled and enabled.

Julien.