Fix the problems exposed by the callingconv1.d test case. The first was that unless otherwise specified, inputs are assumed to be in registers even if they specify a "matching output" that's in memory. While testing that fix, I also ran into a bug causing the generated "matching output" for any input was always the first one instead of the correct one.

// this head contains stuff used by all the IR

#ifndef LDC_IR_IR_H
#define LDC_IR_IR_H

#include "ir/irforw.h"
#include "root.h"

struct IrBase : Object
{
    virtual ~IrBase() {}
};

#endif