[Patch, Fortran] Use -huge()-1 as most negative integer for maxval/maxloc (PR30512)

[Brooks Moses]

Tobias Burnus wrote:
> Thomas Koenig wrote:
>> This is OK, with a few minor nits:
>>   
> I'm not sure I understand the nits correctly.
[...]
>> This should read
>>   
>>> -  /* Most negative(-HUGE) for maxval, most positive (-HUGE) for minval.  */
>>> +  /* Most negative(-HUGE) for maxval, most positive (+HUGE) for minval.  */
> 
> I think the way it is in my patch is commentwise correct. In my tree it
> currently (with patch) reads as:
[...]

This is why it's helpful for people to actually explain the differences 
they're suggesting!

In this case, the difference Thomas is suggesting is that "positive" 
should be spelled correctly -- you've left off the final "e" in your 
version of the comment.

> While I agree that one could improve the wording, I think using
> "(-HUGE-1)" is confusing for BT_REAL.
> How about something like the following?
> 
>   /* Most negative for maxloc, most positiv (+HUGE) for minloc.
>      Most negative is -HUGE for BT_REAL and -HUGE-1 for BT_INTEGER.  */

That seems reasonably clear, on that part.  Though I think the comment 
as a whole could use some more clarifying -- it doesn't say what it's 
referring _to_ (and didn't in the original; this isn't your fault).

I'll suggest (rewrap, indent as needed):

/* We start with the most negative possible value for MAXLOC, and the 
most positive possible value for MINLOC.  The most negative possible 
value is -HUGE for BT_REAL and (-HUGE - 1) for BT_INTEGER; the most 
positive possible value is HUGE in both cases.  */

Also, I just noticed -- in your libgfortran patches, you end up using 
-HUGE-1 for both integers and reals.  I presume on reals that just ends 
up being the same as -HUGE?

- Brooks