Method kill

chapter02/src/main/java/com/seaofnodes/simple/node/Node.java:171–178

Kill a Node with no uses , by setting all of its defs to null. This may recursively kill more Nodes and is basically dead code elimination. This function is co-recursive with #setDef.

( )

     * code elimination.  This function is co-recursive with {@link #setDef}.
     */
    public void kill( ) {
        assert isUnused();      // Has no uses, so it is dead
        for( int i=0; i<nIns(); i++ )
            setDef(i,null);  // Set all inputs to null, recursively killing unused Nodes
        _inputs.clear();
        _type=null;             // Flag as dead
        assert isDead();        // Really dead now
    }

    // Mostly used for asserts and printing.
    boolean isDead() { return isUnused() && nIns()==0 && _type==null; }