for (ListIterator<AbstractInsnNode> it = m.instructions.iterator(); it.hasNext(); )
{
AbstractInsnNode insnNode = it.next();
if (insnNode.getType() == AbstractInsnNode.FIELD_INSN)
{
FieldInsnNode fi = (FieldInsnNode)insnNode;
if (itemField.name.equals(fi.name) && fi.getOpcode() == Opcodes.GETFIELD)
{
it.remove();
MethodInsnNode replace = new MethodInsnNode(Opcodes.INVOKEVIRTUAL, "net/minecraft/item/ItemStack",getItemMethod.name, getItemMethod.desc, false);
it.add(replace);
}