code: private void attemptMatch(BasicBlock basicBlock, BasicBlock.InstructionIterator instructionIterator)
              throws DataflowAnalysisException {
          work(new State(basicBlock, instructionIterator, pattern.getFirst()));
      }
docs: Attempt to begin a match.
  
  @param basicBlock
  the basic block
  @param instructionIterator
  the instruction iterator positioned just before the first
  instruction to be matched