Any usable SIMD implementation?

[Walter Bright via Digitalmars-d]

On 4/4/2016 2:11 PM, jmh530 wrote:
> version(D_SIMD) will tell you when SIMD is implemented, but not what type of
> SIMD.

The first SIMD level.

> For instance, if I am on a machine that can use AVX2 instructions, then
> code in a version(D_SIMD) block will execute, but it should also execute if the
> processor only supports SSE4. What if the writer of an SIMD library wants to
> have code execute differently if SSE4 is detected instead of AVX2?

Use a runtime switch (see core.cpuid).