VM.assert (aBlock != bBlock
VM._assert (aBlock != bBlock
  private OPT_Instruction dominanceSuccessor (OPT_Instruction a,					      OPT_Instruction b)  {    OPT_BasicBlock aBlock = getBlock (a);    OPT_BasicBlock bBlock = getBlock (b);    if (VM.VerifyAssertions)      VM.assert (aBlock != bBlock		 && dominator.dominates (aBlock, bBlock));        OPT_BasicBlock last = null;        while (bBlock != aBlock) {      last = bBlock;      bBlock = dominator.getParent (bBlock);    }    return last.firstInstruction();  }