SSA (static single assignment)

DataFlowGraph *dfg = DataFlowGraph([]);

foreach (BasicBlock)bb in (DataFlowGraph)dfg->get_BasicBlocks() {

    foreach (BasicBlock)preProc in (BasicBlock)bb->get_PreProcessor() {  

        pre_aLiveOutList = preProc->get_aLiveOutRegs();

        foreach (Register)inReg in (BasicBlock)bb->get_aLiveInRegs() {

            if( pre_aLiveOutList.find(inReg) != Pre_aLiveOutList.end() ) {

                (Register)OutReg = preProc->get_Reg(inReg->get_ID());

                if( !PHI_Exist(OutReg,InReg) ) {

                     # deep copy the old register items 2 new register, such as "procs", "succs"...
                     { new_OutReg, new_InReg } = PHI_Insert(OutReg,InReg);

                     # remove the old register pointer
                     bb->remove_reg(InReg);
                     bb->set_reg(new_InReg);

                     # update the graph
                     preProc->remove_reg(OutReg);
                     PreProc->set_reg(new_OutReg);   
               }

            }
       }
   }
}


#########################
# B1:{ a=1; }; B2:{ a=2; };  B3:{ a=a+1; }
# E1:{B1->B3}; E2{B2->B3};
#
# SSA graph
# B1: { a(1)=1; }; B2:{ a(2)=2; }; B3:{ phi a(3):[ B1:a(1), B2:a(2)]; a(3)=a(3)+1; }

Refs: SSA wiki http://en.wikipedia.org/wiki/Static_single_assignment_form Use-define_chain for load store http://en.wikipedia.org/wiki/Use-define_chain