[LLVMdev] [RFC] 3-bit Waymarking

[Chris Lattner]

On Apr 22, 2014, at 12:26 PM, Gabor Greif <ggreif at gmail.com> wrote:
>>> I do not have the equipment to perform a compile-time measurement. How
>>> do folks benchmark for this nowadays? Is it a viable alternative to
>>> bring the changes to ToT and compare speedups/slowdowns in the nightly
>>> builds retrospectively?
>> 
>> I saw the slides, it looks very interesting.  Have you actually measured any
>> memory wins from this?
> 
> Hi Chris,
> 
> there are no memory savings, Use has still 3 pointers (the 4->3
> reduction happened back in 2008). What should be faster with the new
> algorithm are the "value_use_iterator::operator->" operators (i.e.
> finding all Users of a Value).

Ah, ok.  If you're looking for performance benchmarks, you could look at LTO time of something large, in that a majority of the time is spent in the mid-level optimizer.

-Chris