cxxrtl: avoid unused variable warning for transparent $memrd ports. NFC.

diff --git a/backends/cxxrtl/cxxrtl_backend.cc b/backends/cxxrtl/cxxrtl_backend.cc
index 909e1325d1056cbe7991285771ce1f305eae933f..e48c5a403f73a4c4b001403ca5946d2e5cf67b17 100644 (file)
--- a/backends/cxxrtl/cxxrtl_backend.cc
+++ b/backends/cxxrtl/cxxrtl_backend.cc
@@ -1134,31 +1134,33 @@ struct CxxrtlWorker {
                                f << indent << "if(" << valid_index_temp << ".valid) {\n";
                                inc_indent();
                                        if (writable_memories[memory]) {
-                                               std::string addr_temp = fresh_temporary();
-                                               f << indent << "const value<" << cell->getPort(ID::ADDR).size() << "> &" << addr_temp << " = ";
-                                               dump_sigspec_rhs(cell->getPort(ID::ADDR));
-                                               f << ";\n";
                                                std::string lhs_temp = fresh_temporary();
                                                f << indent << "value<" << memory->width << "> " << lhs_temp << " = "
                                                            << mangle(memory) << "[" << valid_index_temp << ".index];\n";
                                                std::vector<const RTLIL::Cell*> memwr_cells(transparent_for[cell].begin(), transparent_for[cell].end());
-                                               std::sort(memwr_cells.begin(), memwr_cells.end(),
-                                                       [](const RTLIL::Cell *a, const RTLIL::Cell *b) {
-                                                               return a->getParam(ID::PRIORITY).as_int() < b->getParam(ID::PRIORITY).as_int();
-                                                       });
-                                               for (auto memwr_cell : memwr_cells) {
-                                                       f << indent << "if (" << addr_temp << " == ";
-                                                       dump_sigspec_rhs(memwr_cell->getPort(ID::ADDR));
-                                                       f << ") {\n";
-                                                       inc_indent();
-                                                               f << indent << lhs_temp << " = " << lhs_temp;
-                                                               f << ".update(";
-                                                               dump_sigspec_rhs(memwr_cell->getPort(ID::DATA));
-                                                               f << ", ";
-                                                               dump_sigspec_rhs(memwr_cell->getPort(ID::EN));
-                                                               f << ");\n";
-                                                       dec_indent();
-                                                       f << indent << "}\n";
+                                               if (!memwr_cells.empty()) {
+                                                       std::string addr_temp = fresh_temporary();
+                                                       f << indent << "const value<" << cell->getPort(ID::ADDR).size() << "> &" << addr_temp << " = ";
+                                                       dump_sigspec_rhs(cell->getPort(ID::ADDR));
+                                                       f << ";\n";
+                                                       std::sort(memwr_cells.begin(), memwr_cells.end(),
+                                                               [](const RTLIL::Cell *a, const RTLIL::Cell *b) {
+                                                                       return a->getParam(ID::PRIORITY).as_int() < b->getParam(ID::PRIORITY).as_int();
+                                                               });
+                                                       for (auto memwr_cell : memwr_cells) {
+                                                               f << indent << "if (" << addr_temp << " == ";
+                                                               dump_sigspec_rhs(memwr_cell->getPort(ID::ADDR));
+                                                               f << ") {\n";
+                                                               inc_indent();
+                                                                       f << indent << lhs_temp << " = " << lhs_temp;
+                                                                       f << ".update(";
+                                                                       dump_sigspec_rhs(memwr_cell->getPort(ID::DATA));
+                                                                       f << ", ";
+                                                                       dump_sigspec_rhs(memwr_cell->getPort(ID::EN));
+                                                                       f << ");\n";
+                                                               dec_indent();
+                                                               f << indent << "}\n";
+                                                       }
                                                }
                                                f << indent;
                                                dump_sigspec_lhs(cell->getPort(ID::DATA));