Added "equiv_struct -fwonly"

diff --git a/passes/equiv/equiv_struct.cc b/passes/equiv/equiv_struct.cc
index 714470ee5e6c4e58586874f3517d69bbae1e2b54..2c85d2d3cd949fb271152b65ff0ddefe0f70050b 100644 (file)
--- a/passes/equiv/equiv_struct.cc
+++ b/passes/equiv/equiv_struct.cc
@@ -32,6 +32,8 @@ struct EquivStructWorker
        bool mode_icells;
        int merge_count;
 
+       const pool<IdString> &fwonly_cells;
+
        struct merge_key_t
        {
                IdString type;
@@ -114,9 +116,9 @@ struct EquivStructWorker
                module->remove(cell_b);
        }
 
-       EquivStructWorker(Module *module, bool mode_fwd, bool mode_icells, int iter_num) :
+       EquivStructWorker(Module *module, bool mode_fwd, bool mode_icells, const pool<IdString> &fwonly_cells, int iter_num) :
                        module(module), sigmap(module), equiv_bits(module),
-                       mode_fwd(mode_fwd), mode_icells(mode_icells), merge_count(0)
+                       mode_fwd(mode_fwd), mode_icells(mode_icells), merge_count(0), fwonly_cells(fwonly_cells)
        {
                log("  Starting iteration %d.\n", iter_num);
 
@@ -222,7 +224,7 @@ struct EquivStructWorker
                                        }
                                }
 
-                               if (phase && cells_type == "$equiv")
+                               if (phase && fwonly_cells.count(cells_type))
                                        continue;
 
                                if (GetSize(gold_cells) > 1 || GetSize(gate_cells) > 1 || GetSize(other_cells) > 1)
@@ -295,10 +297,15 @@ struct EquivStructPass : public Pass {
                log("\n");
                log("    -fwd\n");
                log("        by default this command performans forward sweeps until nothing can\n");
-               log("        be merged by forwards sweeps, the backward sweeps until forward\n");
+               log("        be merged by forwards sweeps, then backward sweeps until forward\n");
                log("        sweeps are effective again. with this option set only forward sweeps\n");
                log("        are performed.\n");
                log("\n");
+               log("    -fwonly <cell_type>\n");
+               log("        add the specified cell type to the list of cell types that are only\n");
+               log("        merged in forward sweeps and never in backward sweeps. $equiv is in\n");
+               log("        this list automatically.\n");
+               log("\n");
                log("    -icells\n");
                log("        by default, the internal RTL and gate cell types are ignored. add\n");
                log("        this option to also process those cell types with this command.\n");
@@ -309,6 +316,7 @@ struct EquivStructPass : public Pass {
        }
        virtual void execute(std::vector<std::string> args, Design *design)
        {
+               pool<IdString> fwonly_cells({ "$equiv" });
                bool mode_icells = false;
                bool mode_fwd = false;
                int max_iter = -1;
@@ -325,6 +333,10 @@ struct EquivStructPass : public Pass {
                                mode_icells = true;
                                continue;
                        }
+                       if (args[argidx] == "-fwonly" && argidx+1 < args.size()) {
+                               fwonly_cells.insert(RTLIL::escape_id(args[++argidx]));
+                               continue;
+                       }
                        if (args[argidx] == "-maxiter" && argidx+1 < args.size()) {
                                max_iter = atoi(args[++argidx].c_str());
                                continue;
@@ -341,7 +353,7 @@ struct EquivStructPass : public Pass {
                                        log("  Reached iteration limit of %d.\n", iter);
                                        break;
                                }
-                               EquivStructWorker worker(module, mode_fwd, mode_icells, iter+1);
+                               EquivStructWorker worker(module, mode_fwd, mode_icells, fwonly_cells, iter+1);
                                if (worker.merge_count == 0)
                                        break;
                                module_merge_count += worker.merge_count;