| 4 | namespace imperative { |
| 5 | |
| 6 | void Subgraph::remove_unused_exprs() { |
| 7 | std::unordered_set<size_t> required_vars = {outputs.begin(), outputs.end()}; |
| 8 | required_vars.erase(0); |
| 9 | for (auto iter = exprs.rbegin(); iter != exprs.rend(); ++iter) { |
| 10 | auto& expr = *iter; |
| 11 | bool required = false; |
| 12 | for (auto output : expr.outputs) { |
| 13 | if (required_vars.count(output)) { |
| 14 | required = true; |
| 15 | break; |
| 16 | } |
| 17 | } |
| 18 | if (required) { |
| 19 | required_vars.insert(expr.inputs.begin(), expr.inputs.end()); |
| 20 | } else { |
| 21 | expr.op = nullptr; |
| 22 | } |
| 23 | } |
| 24 | exprs.erase( |
| 25 | std::remove_if( |
| 26 | exprs.begin(), exprs.end(), |
| 27 | [](auto expr) { return expr.op == nullptr; }), |
| 28 | exprs.end()); |
| 29 | } |
| 30 | |
| 31 | SmallVector<bool> Subgraph::gen_input_mask() { |
| 32 | std::unordered_set<size_t> unused_inputs = {inputs.begin(), inputs.end()}; |