Progress in "share" pass

diff --git a/passes/sat/share.cc b/passes/sat/share.cc
index c04be7c8d60da05e663627e8e8153bba81d45a41..aad53e13c803b1c7573202e4a0c63cc75abeacac 100644 (file)
--- a/passes/sat/share.cc
+++ b/passes/sat/share.cc
@@ -27,7 +27,9 @@
 
 struct ShareWorkerConfig
 {
-       bool opt_all;
+       bool opt_force;
+       bool opt_aggressive;
+       bool opt_fast;
 };
 
 struct ShareWorker
@@ -56,7 +58,7 @@ struct ShareWorker
                        if (!design->selected(module, cell) || !modwalker.ct.cell_known(cell->type))
                                continue;
 
-                       if (config.opt_all) {
+                       if (config.opt_force) {
                                candidates.push_back(cell);
                                continue;
                        }
@@ -68,13 +70,19 @@ struct ShareWorker
                        }
 
                        if (cell->type == "$mul" || cell->type == "$div" || cell->type == "$mod") {
-                               if (cell->parameters.at("\\Y_WIDTH").as_int() > 4)
+                               if (config.opt_aggressive || cell->parameters.at("\\Y_WIDTH").as_int() > 4)
                                        candidates.push_back(cell);
                                continue;
                        }
 
                        if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr") {
-                               if (cell->parameters.at("\\Y_WIDTH").as_int() > 8)
+                               if (config.opt_aggressive || cell->parameters.at("\\Y_WIDTH").as_int() > 8)
+                                       candidates.push_back(cell);
+                               continue;
+                       }
+
+                       if (cell->type == "$add" || cell->type == "$sub") {
+                               if (config.opt_aggressive || cell->parameters.at("\\Y_WIDTH").as_int() > 10)
                                        candidates.push_back(cell);
                                continue;
                        }
@@ -109,7 +117,7 @@ struct ShareWorker
                        return true;
                }
 
-               if (c1->type == "$mul" || c1->type == "$div" || c1->type == "$mod" ||
+               if (c1->type == "$mul" || c1->type == "$div" || c1->type == "$mod" || c1->type == "$add" || c1->type == "$sub" ||
                                c1->type == "$shl" || c1->type == "$shr" || c1->type == "$sshl" || c1->type == "$sshr")
                {
                        if (c1->parameters.at("\\A_SIGNED").as_bool() != c2->parameters.at("\\A_SIGNED").as_bool())
@@ -118,17 +126,20 @@ struct ShareWorker
                        if (c1->parameters.at("\\B_SIGNED").as_bool() != c2->parameters.at("\\B_SIGNED").as_bool())
                                return false;
 
-                       int a1_width = c1->parameters.at("\\A_WIDTH").as_int();
-                       int b1_width = c1->parameters.at("\\B_WIDTH").as_int();
-                       int y1_width = c1->parameters.at("\\Y_WIDTH").as_int();
+                       if (!config.opt_aggressive)
+                       {
+                               int a1_width = c1->parameters.at("\\A_WIDTH").as_int();
+                               int b1_width = c1->parameters.at("\\B_WIDTH").as_int();
+                               int y1_width = c1->parameters.at("\\Y_WIDTH").as_int();
 
-                       int a2_width = c2->parameters.at("\\A_WIDTH").as_int();
-                       int b2_width = c2->parameters.at("\\B_WIDTH").as_int();
-                       int y2_width = c2->parameters.at("\\Y_WIDTH").as_int();
+                               int a2_width = c2->parameters.at("\\A_WIDTH").as_int();
+                               int b2_width = c2->parameters.at("\\B_WIDTH").as_int();
+                               int y2_width = c2->parameters.at("\\Y_WIDTH").as_int();
 
-                       if (std::max(a1_width, a2_width) > 2 * std::min(a1_width, a2_width)) return false;
-                       if (std::max(b1_width, b2_width) > 2 * std::min(b1_width, b2_width)) return false;
-                       if (std::max(y1_width, y2_width) > 2 * std::min(y1_width, y2_width)) return false;
+                               if (std::max(a1_width, a2_width) > 2 * std::min(a1_width, a2_width)) return false;
+                               if (std::max(b1_width, b2_width) > 2 * std::min(b1_width, b2_width)) return false;
+                               if (std::max(y1_width, y2_width) > 2 * std::min(y1_width, y2_width)) return false;
+                       }
 
                        return true;
                }
@@ -365,10 +376,15 @@ struct ShareWorker
 
                                        for (auto &pbit : portbits)
                                                if (sat_cells.count(pbit.cell) == 0 && cone_ct.cell_known(pbit.cell->type)) {
+                                                       if (config.opt_fast && modwalker.cell_outputs[pbit.cell].size() >= 4)
+                                                               continue;
                                                        // log("      Adding cell %s (%s) to SAT problem.\n", log_id(pbit.cell), log_id(pbit.cell->type));
                                                        satgen.importCell(pbit.cell);
                                                        sat_cells.insert(pbit.cell);
                                                }
+
+                                       if (config.opt_fast && sat_cells.size() > 100)
+                                               break;
                                }
 
                                all_ctrl_signals.sort_and_unify();
@@ -409,26 +425,47 @@ struct SharePass : public Pass {
                log("This pass merges shareable resources into a single resource. A SAT solver\n");
                log("is used to determine if two resources are share-able.\n");
                log("\n");
-               log("  -all\n");
+               log("  -force\n");
                log("    Per default the selection of cells that is considered for sharing is\n");
-               log("    narrowed using some built-in heuristics. With this option all selected\n");
+               log("    narrowed using a list of cell types. With this option all selected\n");
                log("    cells are considered for resource sharing.\n");
                log("\n");
                log("    IMPORTANT NOTE: If the -all option is used then no cells with internal\n");
                log("    state must be selected!\n");
                log("\n");
+               log("  -aggressive\n");
+               log("    Per default some heuristics are used to reduce the number of cells\n");
+               log("    considered for resource sharing to only large resources. This options\n");
+               log("    turns this heuristics off, resulting in much more cells being considered\n");
+               log("    for resource sharing.\n");
+               log("\n");
+               log("  -fast\n");
+               log("    Only consider comparable primitive control logic in SAT solving, resulting\n");
+               log("    in much easier SAT problems at the cost of maybe missing some oportunities\n");
+               log("    for resource sharing.\n");
+               log("\n");
        }
        virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
        {
                ShareWorkerConfig config;
-               config.opt_all = false;
+               config.opt_force = false;
+               config.opt_aggressive = false;
+               config.opt_fast = false;
 
                log_header("Executing SHARE pass (SAT-based resource sharing).\n");
 
                size_t argidx;
                for (argidx = 1; argidx < args.size(); argidx++) {
-                       if (args[argidx] == "-all") {
-                               config.opt_all = true;
+                       if (args[argidx] == "-force") {
+                               config.opt_force = true;
+                               continue;
+                       }
+                       if (args[argidx] == "-aggressive") {
+                               config.opt_aggressive = true;
+                               continue;
+                       }
+                       if (args[argidx] == "-fast") {
+                               config.opt_fast = true;
                                continue;
                        }
                        break;