On Sep 3, 2013, at 9:00 AM, Daniel Dunbar <[email protected]> wrote:

> On Sep 3, 2013, at 6:57, "Rafael Espíndola" <[email protected]> 
> 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.

Two reasons:

1) -O1 doesn't actually mean anything.  It is the optimization level least 
understood by both the GCC folks and us.  Recently (last 5 years?) there has 
been a move to try to make this "optimize without messing up debug info", but 
this is a new movement.

2) Users who specify -O generally don't know it maps onto -O1.  They almost 
certainly don't want whatever -O1 provides.  In my experience, most are coming 
from Sun, HP or other compilers, where -O was a generally useful flag.

3) There are some benchmarks that pass -O (because of #2), which is ridiculous, 
but reflects some reality that people use -O.  I don't recall what these 
benchmarks were.

These are reasons that I suggested the change.  I really don't like -O1 :-)

-Chris
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