[Interest] SIMD accelerated wrappers for relevant Qt container classes (QVector, ...) or QByteArray?

René J.V. Bertin rjvbertin at gmail.com
Tue May 9 23:19:32 CEST 2017

On Tuesday May 09 2017 22:49:53 Allan Sandfeld Jensen wrote:


> Anything you can write with SIMD arrays is simple enough that the compiler can 
> also auto-vectorize it as well. Just pretend the arrays you have are SIMD 

I've been out of this for a few years but I'd be surprised that were really accurate today. If it were people wouldn't be developing and using things like Vc. I think. I wouldn't at least :)

I *am* willing to believe that auto-vectorised code can outperform hand-written SIMD code (and code using SIMD arrays) for certain classes of problems. I've seen at least one example of that (and that was about 7 years ago already).

> > Also, to get SIMD support and auto-vectorisation you need the correct
> > -march CPU flag, no?
> > 
> You would need that too with any SIMD-library.

Of course, but there you could probably also just use -D__SSE3__ -D__AVX__ etc. 


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