java_g -Xcomp -XX:+VerifyOpto forloop
 
 fails with the following error message:

#
# An unexpected error has been detected by HotSpot Virtual Machine:
#
# Internal Error
(/export1/jdk142-update/ws/fcs/hotspot/src/share/vm/opto/phaseX.hpp, 208 [ Patched ]), pid=15438, tid=11 # # Java VM: Java HotSpot(TM) Server VM (1.4.2_10-b03-debug compiled mode) # # Error:
assert(allow_progress(),"No progress allowed during verification")



forloop.java is a simple for loop program:

public class forloop{
    public static void main(String[] args){
        for ( int i=0; i<100; i++ )
            i= i+1;
    }
}


During the optimization phase, first it optimizes the graph and then if the "VerifyOpto" flag is enabled, then it disables _allow_progress variable and optimizes the graph again. Here the expectation is, the graph should be fully optimized at this point of time and no more optimization is required.Unfortunately in this case, it tries to modify the graph, by removing a dead node. So we are hitting this assert.