[tablegen] PatFrags with a always matchin case

Code Generation
1

Hi,
a rather basic table-gen question, but quite recurring issue I have.

Is there a way to allow PatFrags to always match an input, returning the matching node it self in worst case, without an operation?

For example, now I need to do this:

def NoZeroChange : PatFrags<(ops node:$a),
  [(abs node:$a),
   (sub node:$a, 0)]>;

def HasZero : PatFrags<(ops node:$a),
  [(icmp (NoZeroChange node:$a), 0),
   (icmp node:$a, 0)]>;   <<< I want to avoid this line

I would like something like this:

def NoZeroChange : PatFrags<(ops node:$a),
  [(abs node:$a),
   (sub node:$a, 0),
   (node:$a)]>;    <<<< This is not allowed

def HasZero : PatFrag<(ops node:$a),
  (icmp (NoZeroChange node:$a), 0)>;

This would highly make life easier in not having to expand that by hand, especially useful if the matching patfrag is used in multiple operands:

def ManyArgs : PatFrags<(opt node:$a, node:$b, node:$c, node:$d),
  (int_my_crazyop
   (NoZeroChange node:$a),
   (NoZeroChange node:$b),
   (NoZeroChange node:$c),
   (NoZeroChange node:$d))>;  << A single line instead of 16.

Perhaps is it possible to do an always matching SDNode?

def NoZeroChange : PatFrags<(ops node:$a),
  [(abs node:$a),
   (sub node:$a, 0),
   (True node:$a)]>; ???

Does anyone done something alike this?
Thanks in advance.
Diogo.