D-Programming-Language/druntime — pull request #291 by ibuclaw (2012-08-16 23:24:57+00:00)
Title: __simd implementation available only if D_SIMD.

(re-doing this pull request)

As per the docs:

```D_SIMD - Vector extensions (__vector and __simd) are supported```
http://dlang.org/version.html#PredefinedVersions

The likes of other compilers (such as GDC) may support __vector, but not the extremely DMD centric __simd, so the __simd implementation should be reserved for compilers that use the predefined version D_SIMD.