Fixed to aggressive x-folding in opt_const

diff --git a/passes/opt/opt_const.cc b/passes/opt/opt_const.cc
index 7c82f0fcb5a1878ad0c32b28cc1d86a516572c3e..149bd97d50871bfd67db885c4843dc137a063dd9 100644 (file)
--- a/passes/opt/opt_const.cc
+++ b/passes/opt/opt_const.cc
@@ -28,7 +28,7 @@
 #include <stdio.h>
 #include <set>
 
-bool did_something;
+static bool did_something;
 
 void replace_cell(RTLIL::Module *module, RTLIL::Cell *cell, std::string info, std::string out_port, RTLIL::SigSpec out_val)
 {
@@ -44,7 +44,7 @@ void replace_cell(RTLIL::Module *module, RTLIL::Cell *cell, std::string info, st
        did_something = true;
 }
 
-void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module)
+void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool consume_x)
 {
        if (!design->selected(module))
                return;
@@ -78,8 +78,13 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module)
                        if (input.match(" 0")) ACTION_DO_Y(0);
                        if (input.match("0 ")) ACTION_DO_Y(0);
                        if (input.match("11")) ACTION_DO_Y(1);
-                       if (input.match(" *")) ACTION_DO_Y(x);
-                       if (input.match("* ")) ACTION_DO_Y(x);
+                       if (input.match("**")) ACTION_DO_Y(x);
+                       if (input.match("1*")) ACTION_DO_Y(x);
+                       if (input.match("*1")) ACTION_DO_Y(x);
+                       if (consume_x) {
+                               if (input.match(" *")) ACTION_DO_Y(0);
+                               if (input.match("* ")) ACTION_DO_Y(0);
+                       }
                        if (input.match(" 1")) ACTION_DO("\\Y", input.extract(1, 1));
                        if (input.match("1 ")) ACTION_DO("\\Y", input.extract(0, 1));
                }
@@ -92,8 +97,13 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module)
                        if (input.match(" 1")) ACTION_DO_Y(1);
                        if (input.match("1 ")) ACTION_DO_Y(1);
                        if (input.match("00")) ACTION_DO_Y(0);
-                       if (input.match(" *")) ACTION_DO_Y(x);
-                       if (input.match("* ")) ACTION_DO_Y(x);
+                       if (input.match("**")) ACTION_DO_Y(x);
+                       if (input.match("0*")) ACTION_DO_Y(x);
+                       if (input.match("*0")) ACTION_DO_Y(x);
+                       if (consume_x) {
+                               if (input.match(" *")) ACTION_DO_Y(1);
+                               if (input.match("* ")) ACTION_DO_Y(1);
+                       }
                        if (input.match(" 0")) ACTION_DO("\\Y", input.extract(1, 1));
                        if (input.match("0 ")) ACTION_DO("\\Y", input.extract(0, 1));
                }
@@ -308,8 +318,11 @@ struct OptConstPass : public Pass {
 
                for (auto &mod_it : design->modules)
                        do {
-                               did_something = false;
-                               replace_const_cells(design, mod_it.second);
+                               do {
+                                       did_something = false;
+                                       replace_const_cells(design, mod_it.second, false);
+                               } while (did_something);
+                               replace_const_cells(design, mod_it.second, true);
                        } while (did_something);
 
                log_pop();