Files
triton/lib/codegen/optimize_dce.cpp
2019-07-29 17:06:20 -07:00

62 lines
1.9 KiB
C++

#include "triton/ir/function.h"
#include "triton/ir/basic_block.h"
#include "triton/ir/module.h"
#include "triton/ir/cfg.h"
#include "triton/codegen/optimize_dce.h"
namespace triton {
namespace codegen{
void optimize_dce::run(ir::module &mod) {
std::list<ir::instruction*> work_list;
std::set<ir::instruction*> marked;
// initialize work-list
for(ir::function *fn: mod.get_function_list()){
std::vector<ir::basic_block*> rpo = ir::cfg::reverse_post_order(fn);
// iterate through blocks
for(ir::basic_block *block: rpo)
for(ir::instruction *i: block->get_inst_list()){
if(dynamic_cast<ir::io_inst*>(i) || dynamic_cast<ir::copy_to_shared_inst*>(i) || dynamic_cast<ir::return_inst*>(i)
|| dynamic_cast<ir::branch_inst*>(i) || dynamic_cast<ir::cond_branch_inst*>(i)
|| dynamic_cast<ir::atomic_cas_inst*>(i) || dynamic_cast<ir::atomic_exch_inst*>(i) || dynamic_cast<ir::atomic_add_inst*>(i) ){
work_list.push_back(i);
marked.insert(i);
}
}
}
// mark -- ignore branches
while(!work_list.empty()){
ir::instruction* current = work_list.back();
work_list.pop_back();
// mark instruction operands
for(ir::value* op: current->ops()) {
if(auto *i = dynamic_cast<ir::instruction*>(op))
if(marked.insert(i).second)
work_list.push_back(i);
}
// TODO: mark last intstruction of current's reverse-dominance frontier
}
// sweep -- delete non-branch unmarked instructions
std::vector<ir::instruction*> to_delete;
for(ir::function *fn: mod.get_function_list()){
std::vector<ir::basic_block*> rpo = ir::cfg::reverse_post_order(fn);
// iterate through blocks
for(ir::basic_block *block: rpo)
for(ir::instruction *i: block->get_inst_list()){
if(marked.find(i) == marked.end())
to_delete.push_back(i);
}
}
// delete
for(ir::instruction* i: to_delete)
i->erase_from_parent();
}
}
}