Issue #722 correction introduced latches in combinatorial process

[pascalgouedo]

Issue Description

To correct issue #722 a new condition (OP_A_CURRPC) has been added to a case inside a combinatorial process of cv32e40P_id_stage.sv (lines 806 to 828).

      // dependency checks
      always_comb begin
        unique case (alu_op_a_mux_sel)
          OP_A_CURRPC: begin
            if (ctrl_transfer_target_mux_sel == JT_JALR) begin
              apu_read_regs[0]       = regfile_addr_ra_id;
              apu_read_regs_valid[0] = 1'b1;
            end
          end  // OP_A_CURRPC:
          OP_A_REGA_OR_FWD: begin
            apu_read_regs[0]       = regfile_addr_ra_id;
            apu_read_regs_valid[0] = 1'b1;
          end  // OP_A_REGA_OR_FWD:
          OP_A_REGB_OR_FWD, OP_A_REGC_OR_FWD: begin
            apu_read_regs[0]       = regfile_addr_rb_id;
            apu_read_regs_valid[0] = 1'b1;
          end
          default: begin
            apu_read_regs[0]       = regfile_addr_ra_id;
            apu_read_regs_valid[0] = 1'b0;
          end
        endcase
      end

Unfortunately an unconditional else branch has been forgotten together with the if condition inside its behavioural description leading to latches inference by implementation tools.

Component

Component:RTL

Steps to Reproduce

1. git tag cv32e40p_v1.4.1
2. Elaborate command of any implementation tool
3. Log
   Warning: .../cv32e40p_id_stage.sv:806: Netlist for always_comb block contains a latch.

[pascalgouedo]

Resolved with PR #904