static void eliminateRedundantInstructions(analysis::DataflowGraph& dfg,
BlockSet& blocks, iterator block)
{
typedef std::vector<unsigned int> KillList;
KillList killList;
report(" Propagating constants through instructions in BB_" << block->id());
unsigned int index = 0;
for(auto instruction = block->instructions().begin();
instruction != block->instructions().end(); ++instruction)
{
if(!propagateValueToSuccessors(dfg, blocks, instruction))
{
++index;
continue;
}
if(canRemoveInstruction(block, instruction))
{
report(" value is not used, removed it.");
killList.push_back(index);
// schedule the block for more work
// TODO: do this when we consider values in multiple blocks
}
else
{
++index;
}
}
for(KillList::iterator killed = killList.begin();
killed != killList.end(); ++killed)
{
dfg.erase(block, *killed);
}
}
static void eliminateDeadInstructions(analysis::DataflowGraph& dfg,
BlockSet& blocks, iterator block)
{
typedef analysis::DataflowGraph::Block Block;
typedef analysis::DataflowGraph::RegisterSet RegisterSet;
typedef std::vector<unsigned int> KillList;
typedef std::vector<PhiInstructionVector::iterator> PhiKillList;
typedef std::vector<RegisterSet::iterator> AliveKillList;
report(" Eliminating dead instructions from BB_" << block->id());
report(" Removing dead alive out values");
AliveKillList aliveOutKillList;
for(RegisterSet::iterator aliveOut = block->aliveOut().begin();
aliveOut != block->aliveOut().end(); ++aliveOut)
{
if(canRemoveAliveOut(dfg, block, *aliveOut))
{
report(" removed " << aliveOut->id);
aliveOutKillList.push_back(aliveOut);
}
}
for(AliveKillList::iterator killed = aliveOutKillList.begin();
killed != aliveOutKillList.end(); ++killed)
{
block->aliveOut().erase(*killed);
}
KillList killList;
report(" Removing dead instructions");
unsigned int index = 0;
for(InstructionVector::iterator instruction = block->instructions().begin();
instruction != block->instructions().end(); ++instruction)
{
if(canRemoveInstruction(block, instruction))
{
report(" removed '" << instruction->i->toString() << "'");
killList.push_back(index);
// schedule the block for more work
report(" scheduled this block again");
blocks.insert(block);
}
else
{
++index;
}
}
for(KillList::iterator killed = killList.begin();
killed != killList.end(); ++killed)
{
dfg.erase(block, *killed);
}
PhiKillList phiKillList;
report(" Removing dead phi instructions");
for(PhiInstructionVector::iterator phi = block->phis().begin();
phi != block->phis().end(); ++phi)
{
if(canRemovePhi(block, *phi))
{
report(" removed " << phi->d.id);
phiKillList.push_back(phi);
}
}
report(" Removing dead alive in values");
AliveKillList aliveInKillList;
for(RegisterSet::iterator aliveIn = block->aliveIn().begin();
aliveIn != block->aliveIn().end(); ++aliveIn)
{
if(canRemoveAliveIn(block, *aliveIn))
{
report(" removed " << aliveIn->id);
aliveInKillList.push_back(aliveIn);
// schedule the predecessors for more work
for(BlockPointerSet::iterator predecessor =
block->predecessors().begin();
predecessor != block->predecessors().end(); ++predecessor)
{
report(" scheduled predecessor BB_" << (*predecessor)->id());
blocks.insert(*predecessor);
}
}
}
for(AliveKillList::iterator killed = aliveInKillList.begin();
killed != aliveInKillList.end(); ++killed)
{
block->aliveIn().erase(*killed);
}
}