Properly construct $live and $fair cells from "if (...) assume/assert (s_eventually...

Fixes https://github.com/YosysHQ/SymbiYosys/issues/59

Signed-off-by: Clifford Wolf <clifford@clifford.at>

diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 86dd80c6507964e60ad21a85b011705422c7c9d4..52fcf3ee779c65423f1e563cfcd60624f2236899 100644 (file)
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -1530,10 +1530,16 @@ skip_dynamic_range_lvalue_expansion:;
                current_scope[wire_en->str] = wire_en;
                while (wire_en->simplify(true, false, false, 1, -1, false, false)) { }
 
-               std::vector<RTLIL::State> x_bit;
-               x_bit.push_back(RTLIL::State::Sx);
+               AstNode *check_defval;
+               if (type == AST_LIVE || type == AST_FAIR) {
+                       check_defval = new AstNode(AST_REDUCE_BOOL, children[0]->clone());
+               } else {
+                       std::vector<RTLIL::State> x_bit;
+                       x_bit.push_back(RTLIL::State::Sx);
+                       check_defval = mkconst_bits(x_bit, false);
+               }
 
-               AstNode *assign_check = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(x_bit, false));
+               AstNode *assign_check = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), check_defval);
                assign_check->children[0]->str = id_check;
                assign_check->children[0]->was_checked = true;
 
@@ -1546,9 +1552,13 @@ skip_dynamic_range_lvalue_expansion:;
                default_signals->children.push_back(assign_en);
                current_top_block->children.insert(current_top_block->children.begin(), default_signals);
 
-               assign_check = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), new AstNode(AST_REDUCE_BOOL, children[0]->clone()));
-               assign_check->children[0]->str = id_check;
-               assign_check->children[0]->was_checked = true;
+               if (type == AST_LIVE || type == AST_FAIR) {
+                       assign_check = nullptr;
+               } else {
+                       assign_check = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), new AstNode(AST_REDUCE_BOOL, children[0]->clone()));
+                       assign_check->children[0]->str = id_check;
+                       assign_check->children[0]->was_checked = true;
+               }
 
                if (current_always == nullptr || current_always->type != AST_INITIAL) {
                        assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_int(1, false, 1));
@@ -1560,7 +1570,8 @@ skip_dynamic_range_lvalue_expansion:;
                assign_en->children[0]->was_checked = true;
 
                newNode = new AstNode(AST_BLOCK);
-               newNode->children.push_back(assign_check);
+               if (assign_check != nullptr)
+                       newNode->children.push_back(assign_check);
                newNode->children.push_back(assign_en);
 
                AstNode *assertnode = new AstNode(type);