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

[Howard Hinnant]

On May 12, 2010, at 1:47 AM, Jeffrey Yasskin wrote:

> 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?

I haven't a chance to look at this.

-Howard