Function mkIRCAS 

pub unsafe extern "C" fn mkIRCAS(
    oldHi: IRTemp,
    oldLo: IRTemp,
    end: IREndness,
    addr: *mut IRExpr,
    expdHi: *mut IRExpr,
    expdLo: *mut IRExpr,
    dataHi: *mut IRExpr,
    dataLo: *mut IRExpr,
) -> *mut IRCAS