RFR(S): 8187822: C2 conditonal move optimization might create broken graph

[Roland Westrelin]

> My only concern now if there is a case when data node has control edge
> pointing to branch of diamond and depends on If's condition (NULL
> check). Can this happen?

These:

  // Check for ops pinned in an arm of the diamond.
  // Can't remove the control flow in this case
  if (lp->outcnt() > 1) return NULL;
  if (rp->outcnt() > 1) return NULL;

prevent it, right?

Roland.