Walter Bright:
Making SIMD code that delivers performance turns out to be a highly quirky and subtle exercise, one that is resistant to formalization.
I have written some SIMD code, with mixed results, so I understand part of such problems, despite my total experience on such things is limited.
Despite those problems and their failures I think it's important to support computer scientists that try to invent languages that try to offer medium-level means to write such kind of code :-) Reading and studying CS papers is important.
Manu is on the daily front lines of doing competitive, real world SIMD programming. He leads a team doing SIMD work. Hence, I am going to strongly weight his opinions on any high level SIMD design constructs.
I respect both Manu and his work (and you Walter are the one at the top of my list of programming heroes).
Interestingly, both of us have rejected the "auto-vectorization" approach popular in C/C++ compilers, for very different reasons.
The authors of that paper too have rejected it. It doesn't give enough semantics to the compilers. They have explored a different solution.
Bye, bearophile
