static arrays becoming value types

[Don]

bearophile wrote:
> Don:
> 
>> I think this change is mandatory. We need it for SIMD operations.<
> 
> Why? Why the compiler can't optimize things and perform SIMD operations with the fixed-sized array semantics of D1? (I ask this for LDC too, that's mostly D1 still).
> 
> Bye,
> bearophile
Because they are passed by reference. It certainly can't do it on D1:

float dot(float[4] x) {
    x[3] = 4.5; // surprise!
    return 0;
}

void main()
{
   float[4] a;
   a[3]= 0;
   float x = dot(a);
   assert(a[3]==0); // FAILS!
}