[cfe-dev] [LLVMdev] New libc++ LLVM Subproject

[Jeffrey Yasskin]

On Tue, May 11, 2010 at 7:24 PM, Howard Hinnant <hhinnant at apple.com> wrote:
> On May 11, 2010, at 9:32 PM, David Leimbach wrote:
>
>>
>> libc++:
>>
>> 5 seconds
>>
>> libstdc++:
>>
>> 22 seconds
>>
>> (smaller is better)
>>
>> Is this libstdc++ with or without rvalue references?
>>
>> How about compile times?  Having used Go a bit, I've been quite fond of how short the code, compile, test loop ends up being.
>
> Tonight compile times look worse.  This isn't completely unexpected as the code size of the libc++ sort is larger than the libstdc++ sort.


That raises an interesting question. Larger sort code will invalidate
more of the instruction cache, so one may only want to use the
larger-but-faster sort for hot sorts, while colder code should use a
smaller sort even if it's somewhat slower. Do you guys have any ideas
on how to automate that choice?

Jeffrey