changes towards a canonical representation of comparisons: * new createNullCheckGuard helper method on CiLoweringTool * replaced NullCheckNode with IsNullNode * GuardNode and FixedGuardNode can be negated * keep a list of conditions that are true/false in CheckCastEliminationPhase * FixedGuardNode has only one condition * GraphBuilderPhase creates canonical CompareNodes * BooleanNodes can negate their usages * added junit test for canonicalized compares * removed junit test for negated instanceof * added more thorough graph comparison for junit tests * CheckCastEliminationPhase keeps track of conditions that are known to be true/false

README:
  This file should be located at the top of the hotspot Mercurial repository.

  See http://openjdk.java.net/ for more information about the OpenJDK.

  See ../README-builds.html for complete details on build machine requirements.

Simple Build Instructions:

    cd make && gnumake
     
  The files that will be imported into the jdk build will be in the "build"
  directory.