An alternative approach is to have one module per architecture or compiler.
You mean like something like std.simd.x86_gdc? In this case a user would need to write a different version of his code for each compiler or write his own wrappers (which is basically what we have now). This could cause a lot of redundant work. What is worse, some people wouldn't bother, and then we would have code that only works with one D compiler.
