diff --git a/passes/cmds/splitcells.cc b/passes/cmds/splitcells.cc
index 15279e6dd..833672b39 100644
--- a/passes/cmds/splitcells.cc
+++ b/passes/cmds/splitcells.cc
@@ -188,8 +188,8 @@ struct SplitcellsWorker
 				std::string base_name = cell->name.str();
 				IdString slice_name;
 				if (blast) {
-					// Strip existing brackets from cell name
-					size_t bracket_pos = base_name.find('[');
+					// Strip existing '[' or '.' from cell name
+					size_t bracket_pos = base_name.find_first_of('[.');
 					if (bracket_pos != std::string::npos) {
 						base_name = base_name.substr(0, bracket_pos);
 					}
@@ -205,12 +205,12 @@ struct SplitcellsWorker
 							// Extract bit offset from the wire (ex: 0)
 							int bit_offset = user_index(slice_lsb);
 
-							// Concatenate wire index (ex: \Memory[0] -> [0]) to the bit offset (ex: [0][bit])
-							size_t bracket_pos = wire_name.find('[');
+							// Concatenate struct attribute or wire index (ex: \Memory[0] -> [0]) to the bit offset
+							size_t bracket_pos = wire_name.find_first_of('[.');
 							if (bracket_pos != std::string::npos) {
 									wire_indices = wire_name.substr(bracket_pos) + stringf(
 										"%c%d%c", format[0], bit_offset, format[1]);
-							} else { // no brackets, so no concatenation using wire, use slice_lsb + name_lsb offset instead
+							} else { // no '[' or '.', so no concatenation using wire, use slice_lsb + name_lsb offset instead
 									wire_indices = stringf(
 										"%c%d%c", format[0], slice_lsb + wire_offset, format[1]);
 							}
diff --git a/passes/silimate/reg_rename.cc b/passes/silimate/reg_rename.cc
index bc254e266..73f94c6df 100644
--- a/passes/silimate/reg_rename.cc
+++ b/passes/silimate/reg_rename.cc
@@ -108,16 +108,10 @@ struct RegRenameInstance {
 				size_t last_open = cellName.rfind('[');
 				size_t last_close = cellName.rfind(']');
 				if (last_open != std::string::npos && last_close != std::string::npos && last_close > last_open) {
-
-						// Check that bracket content is just a single bit index
-						std::string inner = cellName.substr(last_open + 1, last_close - last_open - 1);
-						if (!inner.empty() && inner.find_first_not_of("0123456789") == std::string::npos) {
-							wireName = cellName.substr(0, last_open);
-							bitIndex = std::stoi(inner);
-						} else {
-							wireName = cellName;
-							bitIndex = 0;
-						}
+					// Check that bracket content is just a single bit index
+					std::string inner = cellName.substr(last_open + 1, last_close - last_open - 1);
+					wireName = cellName.substr(0, last_open);
+					bitIndex = std::stoi(inner);
 				} else {
 					wireName = cellName;
 					bitIndex = 0;
@@ -312,13 +306,9 @@ struct RegRenamePass : public Pass {
 					if (!signal_name.empty() && signal_name.back() == ']') {
 						size_t open = signal_name.rfind('[');
 						if (open != std::string::npos) {
-							std::string inner = signal_name.substr(open + 1,
-																										signal_name.size() - open - 2);
-							// Check for alphabetical characters since they can be contained in brackets in a wire name.
-							if (!inner.empty() && inner.find_first_not_of("0123456789:") == std::string::npos) {
-								signal_bits = signal_name.substr(open);
-								signal_name.erase(open);
-							}
+							std::string inner = signal_name.substr(open + 1, signal_name.size() - open - 2);
+							signal_bits = signal_name.substr(open);
+							signal_name.erase(open);
 						}
 					}