Make == for associative arrays test for equality, not identity. _aaEq was added to runtime/internal/aaA.d which forwards to TypeInfo_AssociativeArray.equals in genobj.d. On the codegen side, DtoAAEquals was added to gen/aa.cpp and is called from EqualExp::toElem in gen/toir.cpp. I assume that the frontend will produce an error if == is used on associative arrays of different type. This fixes DMD bug 1429.

module bug27;

int func(int a, int b)
{
    if (a == b)
        return 0;
    else if (a < b)
        return -1;
    else
        return 1;
}

void main()
{
    int i = func(3,4);
    assert(i == -1);
}