sample_rtl_bugs.csv

bug_id,bug_type,severity,buggy_snippet,fixed_snippet,description,fix_patch,verilog_ref,tool
rtl_001,LATCH_INFERRED,WARNING,"always @(*) begin
  if (sel == 2'b00) out = a;
  else if (sel == 2'b01) out = b;
end","always @(*) begin
  case (sel)
    2'b00: out = a;
    2'b01: out = b;
    default: out = '0;
  endcase
end",Incomplete if-else in combinational always block infers latch on out,Replace if-else with case statement and add default branch,mux.v:12,OpenROAD
rtl_002,MULTIDRIVEN_NET,WARNING,"assign net_reset_sync = rst_gen_out;
assign net_reset_sync = por_cell_rst;",assign net_reset_sync = rst_gen_out | por_cell_rst;,Two concurrent assign statements drive the same net causing contention,Merge drivers using OR gate into single assign statement,reset_ctrl.v:15,OpenROAD
rtl_003,TIMING_VIOLATION,ERROR,"always @(posedge clk) begin
  sum <= a + b + c + d + e + f;
end","always @(posedge clk) begin
  stage1 <= a + b;
  stage2 <= c + d;
  stage3 <= e + f;
end
always @(posedge clk) begin
  sum <= stage1 + stage2 + stage3;
end",Deep combinational path in single-cycle adder causes WNS violation,Pipeline the adder across two clock cycles using intermediate registers,adder.v:42,OpenROAD
rtl_004,COMBINATIONAL_LOOP,ERROR,"assign grant = req & ~busy;
assign busy  = grant & processing;","always @(posedge clk) begin
  grant <= req & ~busy;
end
assign busy = grant & processing;",Combinational feedback loop: req->grant->busy->grant,Register the grant signal to break the combinational loop,scheduler.v:88,OpenROAD
rtl_005,CLOCK_DOMAIN_CROSSING,WARNING,"always @(posedge clk_fast) begin
  data_out <= data_in_slow;
end","reg data_sync1, data_sync2;
always @(posedge clk_fast) begin
  data_sync1 <= data_in_slow;
  data_sync2 <= data_sync1;
end
assign data_out = data_sync2;",Direct sampling of slow-domain signal in fast-domain without synchronizer,Insert 2-flop synchronizer chain between clock domains,cdc_bridge.v:34,OpenROAD
rtl_006,UNDRIVEN_PORT,WARNING,"module controller(
  input clk,
  input rst,
  input clk_en
);
always @(posedge clk) begin
  if (!rst) state <= IDLE;
end","module controller(
  input clk,
  input rst,
  input clk_en
);
always @(posedge clk) begin
  if (!rst) state <= IDLE;
  else if (clk_en) state <= next_state;
end",Input port clk_en declared but never used in logic,Use clk_en as clock enable condition in always block,controller.v:8,OpenROAD