void main()
{
    align(128) float[128] a;
    assert((cast(size_t)(a.ptr) & 127) == 0);
}

the assert fails. What gives?

align doesn't work in DMD. There's bugreport for a long time.

On Sunday, 30 November 2014 at 13:55:16 UTC, Temtaime wrote:
> align doesn't work in DMD.

It does in some places, but not on local variables. I think the best you can do for them is use the core.simd types which are intrinsicially aligned.