r189218 - Simplify now that -O4 just maps to -O3 and -O is an alias of -O2.

[Daniel Dunbar]

Actually, I think the justification was that it was unclear what -O1's
"semantics" were, and a general opinion that it wasn't a useful level.

-O0 means do nothing, let me debug
-O2 means optimize but don't go crazy in compile time or code size.
-O3 means optimize and go nuts
-O1 means "optimize a little but don't kill my debug info too bad"?
It's not really clear what should be in that level.

That was the justification, at least. There are also arguments against
(like match gcc) but Chris' preference was to have -O be "useful".

 - Daniel


On Sep 3, 2013, at 9:00, Daniel Dunbar <daniel.dunbar at gmail.com> wrote:

> On Sep 3, 2013, at 6:57, "Rafael Espíndola" <rafael.espindola at gmail.com> wrote:
>
>>> I find that a bit surprising, given that -O should mean -O1.
>>> Daniel -- you changed it to mean -O2 in r82131. Any idea why?
>>
>> Ping.
>
> This is something Chris requested, IIRC. I'm not sure I remember the
> motivation beyond that.
>
> - Daniel
>
>>
>> Cheers,
>> Rafael