diff --git a/elaborate.cc b/elaborate.cc
index 8ee1ce374..889a0d831 100644
--- a/elaborate.cc
+++ b/elaborate.cc
@@ -3109,6 +3109,7 @@ NetProc* PEventStatement::elaborate_st(Design*des, NetScope*scope,
 		  break;
 
 		default:
+		  pr = NULL;
 		  assert(0);
 	    }
 
diff --git a/eval_tree.cc b/eval_tree.cc
index 598628dfd..07638bfc7 100644
--- a/eval_tree.cc
+++ b/eval_tree.cc
@@ -381,6 +381,7 @@ NetEConst* NetEBComp::eval_leeq_real_(NetExpr*le, NetExpr*ri, bool eq_flag)
 	    break;
 
 	  default:
+	    lv = 0.0;
 	    cerr << get_fileline() << ": internal error: "
 		 << "Unexpected expression type? " << le->expr_type() << endl;
 	    assert(0);
@@ -401,6 +402,7 @@ NetEConst* NetEBComp::eval_leeq_real_(NetExpr*le, NetExpr*ri, bool eq_flag)
 	    break;
 
 	  default:
+	    rv = 0.0;
 	    cerr << get_fileline() << ": internal error: "
 		 << "Unexpected expression type? " << ri->expr_type() << endl;
 	    assert(0);
@@ -585,6 +587,7 @@ NetEConst* NetEBComp::eval_eqeq_real_(NetExpr*le, NetExpr*ri, bool ne_flag)
 	    break;
 
 	  default:
+	    lv = 0.0;
 	    cerr << get_fileline() << ": internal error: "
 		 << "Unexpected expression type? " << le->expr_type() << endl;
 	    assert(0);
@@ -605,6 +608,7 @@ NetEConst* NetEBComp::eval_eqeq_real_(NetExpr*le, NetExpr*ri, bool ne_flag)
 	    break;
 
 	  default:
+	    rv = 0.0;
 	    cerr << get_fileline() << ": internal error: "
 		 << "Unexpected expression type? " << ri->expr_type() << endl;
 	    assert(0);
diff --git a/expr_synth.cc b/expr_synth.cc
index bd031afe9..3c7e258b8 100644
--- a/expr_synth.cc
+++ b/expr_synth.cc
@@ -200,6 +200,7 @@ NetNet* NetEBBits::synthesize(Design*des, NetScope*scope, NetExpr*root)
 	    gate = new NetLogic(scope, oname, 3, NetLogic::XNOR, width);
 	    break;
 	  default:
+	    gate = NULL;
 	    assert(0);
       }
 
@@ -863,6 +864,7 @@ NetNet* NetEUBits::synthesize(Design*des, NetScope*scope, NetExpr*root)
 	    gate = new NetLogic(scope, oname, 2, NetLogic::NOT, width);
 	    break;
 	  default:
+	    gate = NULL;
 	    assert(0);
       }
 
diff --git a/netlist.cc b/netlist.cc
index add9690f0..5dddbfe9f 100644
--- a/netlist.cc
+++ b/netlist.cc
@@ -2668,6 +2668,7 @@ static DelayType get_loop_delay_type(const NetExpr*expr, const NetProc*proc)
 	    /* This should never happen since delay_type_from_expr() only
 	     * returns three different values. */
 	  default:
+	    result = NO_DELAY;
 	    assert(0);
       }
 
diff --git a/netmisc.cc b/netmisc.cc
index 183d9d47e..f3f2d743a 100644
--- a/netmisc.cc
+++ b/netmisc.cc
@@ -448,6 +448,7 @@ const char *human_readable_op(const char op, bool unary)
 
 	    case 'p': type = "**"; break; // Power
 	    default:
+	      type = "???";
 	      assert(0);
 	}
 	return type;
diff --git a/t-dll-api.cc b/t-dll-api.cc
index e9f6f9538..8f6d19db3 100644
--- a/t-dll-api.cc
+++ b/t-dll-api.cc
@@ -545,6 +545,8 @@ extern "C" unsigned long ivl_expr_uvalue(ivl_expr_t net)
 	    assert(0);
       }
 
+      assert(0);
+      return 0;
 }
 
 extern "C" ivl_variable_type_t ivl_expr_value(ivl_expr_t net)