[cfe-commits] [PATCH] Oz optimization level sets ForceSizeOpt attribute for each function

[Chandler Carruth]

On Mon, Oct 29, 2012 at 1:29 PM, Evan Cheng <evan.cheng at apple.com> wrote:
>
> On Oct 29, 2012, at 1:21 PM, Eric Christopher <echristo at gmail.com> wrote:
>
>> On Thu, Oct 25, 2012 at 8:46 AM, Quentin Colombet <qcolombet at apple.com> wrote:
>>>
>>> On Oct 24, 2012, at 9:25 PM, Chandler Carruth <chandlerc at google.com> wrote:
>>>
>>>> On Wed, Oct 24, 2012 at 8:58 PM, Quentin Colombet <qcolombet at apple.com> wrote:
>>>>> Hello,
>>>>>
>>>>> Following the adding of the new ForceSizeOpt attribute in LLVM (see commit r1664220), I am making a patch for clang to set this attribute on each function when the Oz optimization level is set.
>>>>
>>>> Can you fix the attribute based on the code review feedback first? I'd
>>>> rather not start generating the IR when it's about to change.
>>>
>>> Hi Chandler,
>>>
>>> I am not sure to know which review you are talking about.
>>> From my understanding, according to Eli, it was ok, and according to Evan, it was ok too but may change in the future.
>>> I was not making the future happening now, if it was that you meant :).
>>>
>>
>> This is what he meant, what's the point of doing this as a short term
>> fix when the full fix is both a) not much more work and b) there are
>> objections to the existing patch?
>
> It's not a lot of work except for getting agreement. There is no urgency to make the change to -Os[123] now, there are no driving forces behind it. I'd recommend punting it.
>
> As for the attribute name, I have no strong opinions. It's a obviously open to interpretation.

I think it is important to pick the name well as we'll never be able
to get rid of it, and the name will inform people's assumptions about
how it works.

I don't think we can be lazy about getting the design we want for the
IR's representation (including the names when they indicate that
design!) of optimization levels, because we're just going to confuse
users with mistaken assumptions and expectations. Changing the IR
isn't easy enough at this point for us to try a few things and see
what works.