void DeadCodeEliminationPass::runOnKernel(ir::IRKernel& k)
{
report("Running dead code elimination on kernel " << k.name);
reportE(REPORT_PTX, k);
Analysis* dfgAnalysis = getAnalysis(Analysis::DataflowGraphAnalysis);
assert(dfgAnalysis != 0);
analysis::DataflowGraph& dfg =
*static_cast<analysis::DataflowGraph*>(dfgAnalysis);
assert(dfg.ssa() != analysis::DataflowGraph::SsaType::None);
BlockSet blocks;
report(" Starting by scanning all basic blocks");
for(iterator block = dfg.begin(); block != dfg.end(); ++block)
{
report(" Queueing up BB_" << block->id());
blocks.insert(block);
}
while(!blocks.empty())
{
iterator block = *blocks.begin();
blocks.erase(blocks.begin());
eliminateDeadInstructions(dfg, blocks, block);
}
report("Finished running dead code elimination on kernel " << k.name);
reportE(REPORT_PTX, k);
}
void ConstantPropagationPass::runOnKernel(ir::IRKernel& k)
{
report("Running constant propagation on kernel " << k.name);
Analysis* dfgAnalysis = getAnalysis("DataflowGraphAnalysis");
assert(dfgAnalysis != 0);
analysis::DataflowGraph& dfg =
*static_cast<analysis::DataflowGraph*>(dfgAnalysis);
dfg.convertToSSAType(analysis::DataflowGraph::Minimal);
assert(dfg.ssa() == analysis::DataflowGraph::Minimal);
BlockSet blocks;
report(" Starting by scanning all basic blocks");
for(iterator block = dfg.begin(); block != dfg.end(); ++block)
{
report(" Queueing up BB_" << block->id());
blocks.insert(block);
}
while(!blocks.empty())
{
iterator block = *blocks.begin();
blocks.erase(blocks.begin());
eliminateRedundantInstructions(dfg, blocks, block);
}
report("Finished running constant propagation on kernel " << k.name);
reportE(REPORT_PTX, k);
}
ControlFlowGraph::ConstBlockPointerVector
ControlFlowGraph::executable_sequence() const {
typedef std::unordered_set<const_iterator> BlockSet;
ConstBlockPointerVector sequence;
BlockSet unscheduled;
for(const_iterator i = begin(); i != end(); ++i) {
unscheduled.insert(i);
}
report("Getting executable sequence.");
sequence.push_back(get_entry_block());
unscheduled.erase(get_entry_block());
report(" added " << get_entry_block()->label());
while (!unscheduled.empty()) {
if (sequence.back()->has_fallthrough_edge()) {
const_edge_iterator fallthroughEdge
= sequence.back()->get_fallthrough_edge();
sequence.push_back(fallthroughEdge->tail);
unscheduled.erase(fallthroughEdge->tail);
}
else {
// find a new block, favor branch targets over random blocks
const_iterator next = *unscheduled.begin();
for(const_edge_pointer_iterator
edge = sequence.back()->out_edges.begin();
edge != sequence.back()->out_edges.end(); ++edge)
{
if(unscheduled.count((*edge)->tail) != 0)
{
next = (*edge)->tail;
}
}
// rewind through fallthrough edges to find the beginning of the
// next chain of fall throughs
report(" restarting at " << next->label());
bool rewinding = true;
while (rewinding) {
rewinding = false;
for (const_edge_pointer_iterator
edge = next->in_edges.begin();
edge != next->in_edges.end(); ++edge) {
if ((*edge)->type == Edge::FallThrough) {
assertM(unscheduled.count((*edge)->head) != 0,
(*edge)->head->label()
<< " has multiple fallthrough branches.");
next = (*edge)->head;
report(" rewinding to " << next->label());
rewinding = true;
break;
}
}
}
sequence.push_back(next);
unscheduled.erase(next);
}
report(" added " << sequence.back()->label());
}
return sequence;
}