Re: [boost] [offtopic] C++11 useful trick

Subject: Re: [boost] [offtopic] C++11 useful trick
From: Roland Bock (rbock_at_[hidden])
Date: 2012-07-03 13:50:17

On 2012-07-03 19:36, Eric Niebler wrote:
> On 7/3/2012 9:22 AM, Roland Bock wrote:
>> On 2012-07-03 16:52, Mathias Gaunard wrote:
>>> Given your test, I suggest you benchmark the preprocessed output
>>> rather than the source directly.
>> OK, created preprocessed versions with clang -E and measured again, but
>> the results are similarly close (and way too much under the influence of
>> the sheer amount of bytes that need to be processed).
>>
>> I came up with a new test, see attachments:
>>
>> Without optimization:
>> Eric:
>> real    0m11.457s
>> user    0m11.080s
>> sys     0m0.330s
>>
>> Roland:
>> real    0m11.228s
>> user    0m10.790s
>> sys     0m0.400s
>>
>> With -O3:
>> Eric:
>> real    0m2.910s
>> user    0m2.730s
>> sys     0m0.150s
>>
>> Roland:
>> real    0m2.867s
>> user    0m2.680s
>> sys     0m0.160s
>>
>>
>> Interestingly enough, Eric's version takes a bit longer to compile on my
>> machine:
> Too close to be very meaningful. I find that with TMP, the real costs
> don't become evident until you have a non-trivial program.
>
>> clang version 3.2 (trunk 155315)
>> Target: x86_64-unknown-linux-gnu
>>
>> And clang crashes when I add another row of parameters in Eric's
>> version. No problems with my version...
> I hope you filed a bug. :-)
Will do :-)