simd.swift

// this needs to run with the `-parse-stdlib` command line option passed to swift:
//     swift -parse-stdlib simd.swift

import Swift //Import swift stdlib

struct DoubleX4 {
    var _v: Builtin.Vec4xFPIEEE64
    subscript(_ idx: Int32) -> Double {
        @_transparent
        get {
            let elt = Builtin.extractelement_Vec4xFPIEEE64_Int32(_v, idx._value)
            return Double(_bits: elt)
        }
        @_transparent
        set {
            _v = Builtin.insertelement_Vec4xFPIEEE64_FPIEEE64_Int32(_v, newValue._value, idx._value)
        }
    }
    @_transparent
    init() {
        _v = Builtin.zeroInitializer()
    }
    @_transparent
    init(_bits: Builtin.Vec4xFPIEEE64) {
        _v = _bits
    }
}

extension DoubleX4: CustomDebugStringConvertible {
    var debugDescription: String {
        return "DoubleX4(\((0..<4).map { self[$0] }))"
    }
}

extension DoubleX4 {
    @_transparent
    static func +(lhs: DoubleX4, rhs: DoubleX4) -> DoubleX4 {
        return DoubleX4(_bits: Builtin.fadd_Vec4xFPIEEE64(lhs._v, rhs._v))
    }
}

var d1 = DoubleX4()
d1[0] = 123
d1[2] = 42
print(d1)
var d2 = DoubleX4()
d2[1] = 321
d2[2] = 24
print(d2)
var d3 = d1 + d2
print(d3)