public void addInsnToHead(Insn insn){
  SsaInsn newInsn=SsaInsn.makeFromRop(insn,this);
  insns.add(getCountPhiInsns(),newInsn);
  parent.onInsnAdded(newInsn);
}

public void addInsnToHead ( Insn insn ) { SsaInsn newInsn = SsaInsn . makeFromRop ( insn , this ) ; insns . add ( getCountPhiInsns ( ) , newInsn ) ; parent . onInsnAdded ( newInsn ) ; }
adds an insn to the head of this basic block , just after any phi insns .
