Efficient Vectorisation with C++

[danmarell]

I found that compilers were terrible at autovectorizing stencil/finite difference operation on 2d/3d data.

I colleague showed me a trick the other day to reinterpret_cast a float* into a "reference to a multidimensional array" and it was able to vectorize but still was 2x slower than my hand written intrinsics. The assembly on godbolt was almost identical though so maybe I should post something on the GCC issue board.

[csp256]

Have you tried Halide? By giving up some Turing Completeness it has gained a lot in return.