SIMD on Windows

jerro a at a.com
Sat Jun 29 12:52:17 PDT 2013


> It seems like auto-vectorization to SIMD code may be an ideal 
> strategy (e.g. Java) since it seems that the conditions to get 
> any performance improvement have to be very particular and 
> situational... which is something the compiler may be best 
> suited to handle. Thoughts?

The things is that using SIMD efficiently often requires you to 
organize your data and your algorithm differently, which is 
something that the compiler can't do for you. Another problem is 
that the compiler doesn't know how often different code paths 
will be executed so it can't know how to use SIMD in the best way 
(that could be solved with profile guided optimization, though). 
Alignment restrictions are another thing that can cause problems. 
For those reasons auto-vectorization only works in the simplest 
of cases. But if you want auto-vectorization, GDC and LDC already 
do it.

I recommend watching Manu's talk (as Kiith-Sa has already 
suggested):

http://youtube.com/watch?v=q_39RnxtkgM


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