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Re: [PATCH ppc64,aarch64,alpha 00/15] Improve backend constant generation


On 08/12/2015 08:59 AM, Wilco Dijkstra wrote:
> I looked at the statistics of AArch64 immediate generation a while ago. 
> The interesting thing is ~95% of calls are queries, and the same query is on 
> average repeated 10 times in a row. So (a) it is not important to cache the 
> expansions, and (b) the high repetition rate means a single-entry cache
> has a 90% hitrate. We already have a patch for this and could collect stats
> comparing the approaches. If a single-entry cache can provide a similar 
> benefit as caching all immediates then my preference would be to keep things
> simple and just cache the last query.

Interesting.  That's already more detailed investigation than I'd done.  I had
no idea the queries were so clustered.  I assumed that the queries would be
scattered across various passes, and so the various constants across the
function would get checked in sequence.

I would be very interested in seeing those stats when you've done.


r~


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