Now prefer smallest cells in dfflibmap

diff --git a/passes/techmap/dfflibmap.cc b/passes/techmap/dfflibmap.cc
index 765a606cfd12bd3334add7ac900fa811e51f6b15..6fbd52105f00ee8a5d9c4ff4c93b993625ae3647 100644 (file)
--- a/passes/techmap/dfflibmap.cc
+++ b/passes/techmap/dfflibmap.cc
@@ -106,6 +106,7 @@ static void find_cell(LibertyAst *ast, std::string cell_type, bool clkpol, bool
        LibertyAst *best_cell = NULL;
        std::map<std::string, char> best_cell_ports;
        int best_cell_pins = 0;
+       float best_cell_area = 0;
 
        if (ast->id != "library")
                log_error("Format error in liberty file.\n");
@@ -141,6 +142,11 @@ static void find_cell(LibertyAst *ast, std::string cell_type, bool clkpol, bool
                        this_cell_ports[cell_rst_pin] = 'R';
                this_cell_ports[cell_next_pin] = 'D';
 
+               float area = 0;
+               LibertyAst *ar = cell->find("area");
+               if (ar != NULL && !ar->value.empty())
+                       area = atof(ar->value.c_str());
+
                int num_pins = 0;
                bool found_output = false;
                for (auto pin : cell->children)
@@ -174,14 +180,18 @@ static void find_cell(LibertyAst *ast, std::string cell_type, bool clkpol, bool
                if (!found_output || (best_cell != NULL && num_pins > best_cell_pins))
                        continue;
 
+               if (best_cell != NULL && num_pins == best_cell_pins && area > best_cell_area)
+                       continue;
+
                best_cell = cell;
                best_cell_pins = num_pins;
+               best_cell_area = area;
                best_cell_ports.swap(this_cell_ports);
        continue_cell_loop:;
        }
 
        if (best_cell != NULL) {
-               log("  cell %s is a direct match for cell type %s.\n", best_cell->args[0].c_str(), cell_type.substr(1).c_str());
+               log("  cell %s (pins=%d, area=%.2f) is a direct match for cell type %s.\n", best_cell->args[0].c_str(), best_cell_pins, best_cell_area, cell_type.substr(1).c_str());
                cell_mappings[cell_type].cell_name = best_cell->args[0];
                cell_mappings[cell_type].ports = best_cell_ports;
        }
@@ -192,6 +202,7 @@ static void find_cell_sr(LibertyAst *ast, std::string cell_type, bool clkpol, bo
        LibertyAst *best_cell = NULL;
        std::map<std::string, char> best_cell_ports;
        int best_cell_pins = 0;
+       float best_cell_area = 0;
 
        if (ast->id != "library")
                log_error("Format error in liberty file.\n");
@@ -223,6 +234,11 @@ static void find_cell_sr(LibertyAst *ast, std::string cell_type, bool clkpol, bo
                this_cell_ports[cell_clr_pin] = 'R';
                this_cell_ports[cell_next_pin] = 'D';
 
+               float area = 0;
+               LibertyAst *ar = cell->find("area");
+               if (ar != NULL && !ar->value.empty())
+                       area = atof(ar->value.c_str());
+
                int num_pins = 0;
                bool found_output = false;
                for (auto pin : cell->children)
@@ -256,14 +272,18 @@ static void find_cell_sr(LibertyAst *ast, std::string cell_type, bool clkpol, bo
                if (!found_output || (best_cell != NULL && num_pins > best_cell_pins))
                        continue;
 
+               if (best_cell != NULL && num_pins == best_cell_pins && area > best_cell_area)
+                       continue;
+
                best_cell = cell;
                best_cell_pins = num_pins;
+               best_cell_area = area;
                best_cell_ports.swap(this_cell_ports);
        continue_cell_loop:;
        }
 
        if (best_cell != NULL) {
-               log("  cell %s is a direct match for cell type %s.\n", best_cell->args[0].c_str(), cell_type.substr(1).c_str());
+               log("  cell %s (pins=%d, area=%.2f) is a direct match for cell type %s.\n", best_cell->args[0].c_str(), best_cell_pins, best_cell_area, cell_type.substr(1).c_str());
                cell_mappings[cell_type].cell_name = best_cell->args[0];
                cell_mappings[cell_type].ports = best_cell_ports;
        }