this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
one pair for each predecessor basic block of the current block. Only values of
<a href="#t_firstclass">first class</a> type may be used as the value arguments
-to the PHI node. Only labels be used as the label arguments.<p>
+to the PHI node. Only labels may be used as the label arguments.<p>
There must be no non-phi instructions between the start of a basic block and the
PHI instructions: i.e. PHI instructions must be first in a basic block.<p>