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functional backend: topological sort starts with the output and next states nodes, other nodes get deleted

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This commit is contained in:
Emily Schmidt 2024-07-25 10:35:32 +01:00
parent 7ac0e92d35
commit 8c0f625c3a
5 changed files with 62 additions and 28 deletions
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38
kernel/topo_scc.h
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@ -194,7 +194,7 @@ public:
};
template<typename G, typename ComponentCallback>
void topo_sorted_sccs(G &graph, ComponentCallback component, bool sources_first = false)
class TopoSortedSccs
{
typedef typename G::node_enumerator node_enumerator;
typedef typename G::successor_enumerator successor_enumerator;
@ -210,14 +210,20 @@ void topo_sorted_sccs(G &graph, ComponentCallback component, bool sources_first
{}
};
G &graph;
ComponentCallback component;
std::vector<dfs_entry> dfs_stack;
std::vector<node_type> component_stack;
int next_index = 0;
public:
TopoSortedSccs(G &graph, ComponentCallback component)
: graph(graph), component(component) {}
node_enumerator nodes = graph.enumerate_nodes();
if (sources_first) {
// process all sources (nodes without a successor)
TopoSortedSccs &process_sources() {
node_enumerator nodes = graph.enumerate_nodes();
while (!nodes.finished()) {
node_type node = nodes.next();
successor_enumerator successors = graph.enumerate_successors(node);
@ -231,16 +237,23 @@ void topo_sorted_sccs(G &graph, ComponentCallback component, bool sources_first
graph.dfs_index(node) = INT_MAX;
}
}
nodes = graph.enumerate_nodes();
return *this;
}
// iterate over all nodes to ensure we process the whole graph
while (!nodes.finished()) {
node_type node = nodes.next();
// process all remaining nodes in the graph
TopoSortedSccs &process_all() {
node_enumerator nodes = graph.enumerate_nodes();
// iterate over all nodes to ensure we process the whole graph
while (!nodes.finished())
process(nodes.next());
return *this;
}
// process all nodes that are reachable from a given start node
TopoSortedSccs &process(node_type node) {
// only start a new search if the node wasn't visited yet
if (graph.dfs_index(node) >= 0)
continue;
return *this;
while (true) {
// at this point we're visiting the node for the first time during
// the DFS search
@ -299,7 +312,7 @@ void topo_sorted_sccs(G &graph, ComponentCallback component, bool sources_first
// continues the search at the parent node or returns to
// the outer loop if we already are at the root node.
if (dfs_stack.empty())
goto next_search;
return *this;
auto &dfs_top = dfs_stack.back();
node = dfs_top.node;
@ -336,9 +349,8 @@ void topo_sorted_sccs(G &graph, ComponentCallback component, bool sources_first
}
}
}
next_search:;
}
}
};
YOSYS_NAMESPACE_END