diff --git a/elab_expr.cc b/elab_expr.cc
index 2f92afa27..c1923b83c 100644
--- a/elab_expr.cc
+++ b/elab_expr.cc
@@ -675,10 +675,7 @@ NetExpr* PEBComp::elaborate_expr(Design*des, NetScope*scope,
       NetExpr*tmp = new NetEBComp(op_, lp, rp);
       tmp->set_line(*this);
 
-      tmp = pad_to_width(tmp, expr_wid, *this);
-      tmp->cast_signed(signed_flag_);
-
-      return tmp;
+      return pad_to_width(tmp, expr_wid, signed_flag_, *this);
 }
 
 unsigned PEBLogic::test_width(Design*, NetScope*, width_mode_t&)
@@ -716,10 +713,7 @@ NetExpr*PEBLogic::elaborate_expr(Design*des, NetScope*scope,
       NetExpr*tmp = new NetEBLogic(op_, lp, rp);
       tmp->set_line(*this);
 
-      tmp = pad_to_width(tmp, expr_wid, *this);
-      tmp->cast_signed(signed_flag_);
-
-      return tmp;
+      return pad_to_width(tmp, expr_wid, signed_flag_, *this);
 }
 
 unsigned PEBLeftWidth::test_width(Design*des, NetScope*scope, width_mode_t&mode)
@@ -1035,8 +1029,7 @@ NetExpr*PEBShift::elaborate_expr_leaf(Design*des, NetExpr*lp, NetExpr*rp,
 		  tmp->set_line(*this);
 		  tmp = new NetESelect(lp, tmp, 1);
 		  tmp->set_line(*this);
-		  tmp = pad_to_width(tmp, expr_wid, *this);
-		  tmp->cast_signed(true);
+		  tmp = pad_to_width(tmp, expr_wid, true, *this);
 
                   delete rp;
 		  return tmp;
@@ -1414,23 +1407,7 @@ NetExpr*PECallFunction::cast_to_width_(NetExpr*expr, unsigned wid) const
 		 << " from expr_width()=" << expr->expr_width() << endl;
       }
 
-        /* If the expression is a const, then replace it with a new
-           const. This is a more efficient result. */
-      if (NetEConst*tmp = dynamic_cast<NetEConst*>(expr)) {
-            tmp->cast_signed(signed_flag_);
-            if (wid != tmp->expr_width()) {
-                  tmp = new NetEConst(verinum(tmp->value(), wid));
-                  tmp->set_line(*this);
-                  delete expr;
-            }
-            return tmp;
-      }
-
-      NetESelect*tmp = new NetESelect(expr, 0, wid);
-      tmp->cast_signed(signed_flag_);
-      tmp->set_line(*this);
-
-      return tmp;
+      return cast_to_width(expr, wid, signed_flag_, *this);
 }
 
 /*
@@ -1606,10 +1583,7 @@ NetExpr* PECallFunction::elaborate_sfunc_(Design*des, NetScope*scope,
       if (missing_parms || parm_errors)
             return 0;
 
-      NetExpr*tmp = pad_to_width(fun, expr_wid, *this);
-      tmp->cast_signed(signed_flag_);
-
-      return tmp;
+      return pad_to_width(fun, expr_wid, signed_flag_, *this);
 }
 
 NetExpr* PECallFunction::elaborate_access_func_(Design*des, NetScope*scope,
@@ -1666,10 +1640,7 @@ NetExpr* PECallFunction::elaborate_access_func_(Design*des, NetScope*scope,
       NetExpr*tmp = new NetEAccess(branch, nature);
       tmp->set_line(*this);
 
-      tmp = pad_to_width(tmp, expr_wid, *this);
-      tmp->cast_signed(signed_flag_);
-
-      return tmp;
+      return pad_to_width(tmp, expr_wid, signed_flag_, *this);
 }
 
 /*
@@ -2281,10 +2252,7 @@ NetExpr* PECallFunction::elaborate_base_(Design*des, NetScope*scope, NetScope*ds
 	    if(res->darray_type())
 	        return func;
 
-            NetExpr*tmp = pad_to_width(func, expr_wid, *this);
-            tmp->cast_signed(signed_flag_);
-
-	    return tmp;
+            return pad_to_width(func, expr_wid, signed_flag_, *this);
       }
 
       cerr << get_fileline() << ": internal error: Unable to locate "
@@ -2883,8 +2851,7 @@ NetExpr* PEConcat::elaborate_expr(Design*des, NetScope*scope,
 	    return 0;
       }
 
-      NetExpr*tmp = pad_to_width(concat, expr_wid, *this);
-      tmp->cast_signed(signed_flag_);
+      NetExpr*tmp = pad_to_width(concat, expr_wid, signed_flag_, *this);
 
       concat_depth -= 1;
       return tmp;
@@ -3801,10 +3768,7 @@ NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope,
 
             if (!tmp) return 0;
 
-            tmp = pad_to_width(tmp, expr_wid, *this);
-            tmp->cast_signed(signed_flag_);
-
-            return tmp;
+            return pad_to_width(tmp, expr_wid, signed_flag_, *this);
       }
 
 	// If the identifier names a signal (a register or wire)
@@ -3840,10 +3804,7 @@ NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope,
 		       << ", tmp=" << *tmp << endl;
 	    }
 
-            tmp = pad_to_width(tmp, expr_wid, *this);
-            tmp->cast_signed(signed_flag_);
-
-            return tmp;
+            return pad_to_width(tmp, expr_wid, signed_flag_, *this);
       }
 
 	// If the identifier is a named event
@@ -3943,9 +3904,7 @@ NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope,
 							       member_comp);
 			if (!tmp) return 0;
 
-			tmp = pad_to_width(tmp, expr_wid, *this);
-			tmp->cast_signed(signed_flag_);
-			return tmp;
+			return pad_to_width(tmp, expr_wid, signed_flag_, *this);
 		  }
 
 		  if (net->class_type() != 0) {
@@ -4524,7 +4483,7 @@ NetExpr* PEIdent::elaborate_expr_param_(Design*des,
 		       << "Elaborate parameter <" << path_
 		       << "> as enumeration constant." << *etmp << endl;
 	    tmp = etmp->dup_expr();
-            tmp = pad_to_width(tmp, expr_wid, *this);
+            tmp = pad_to_width(tmp, expr_wid, signed_flag_, *this);
 
       } else {
 	    perm_string name = peek_tail_name(path_);
@@ -6114,7 +6073,7 @@ NetExpr* PEUnary::elaborate_expr(Design*des, NetScope*scope,
 		  }
 		  tmp->set_line(*this);
 	    }
-            tmp = pad_to_width(tmp, expr_wid, *this);
+            tmp = pad_to_width(tmp, expr_wid, signed_flag_, *this);
 	    break;
 
 	  case '&': // Reduction AND
@@ -6132,7 +6091,7 @@ NetExpr* PEUnary::elaborate_expr(Design*des, NetScope*scope,
 	    }
 	    tmp = new NetEUReduce(op_, ip);
 	    tmp->set_line(*this);
-            tmp = pad_to_width(tmp, expr_wid, *this);
+            tmp = pad_to_width(tmp, expr_wid, signed_flag_, *this);
 	    break;
 
 	  case '~':
diff --git a/netmisc.h b/netmisc.h
index 2e2297b15..e0569bce0 100644
--- a/netmisc.h
+++ b/netmisc.h
@@ -59,14 +59,6 @@ inline NetScope* symbol_search(const LineInfo*li,
       return symbol_search(li, des, start, path, net, par, eve, ex1, ex2);
 }
 
-/*
- * This function transforms an expression by padding the high bits
- * with V0 until the expression has the desired width. This may mean
- * not transforming the expression at all, if it is already wide
- * enough.
- */
-extern NetExpr*pad_to_width(NetExpr*expr, unsigned wid, const LineInfo&info);
-
 /*
  * This function transforms an expression by either zero or sign extending
  * the high bits until the expression has the desired width. This may mean
@@ -76,6 +68,13 @@ extern NetExpr*pad_to_width(NetExpr*expr, unsigned wid, const LineInfo&info);
  */
 extern NetExpr*pad_to_width(NetExpr*expr, unsigned wid, bool signed_flag,
 			    const LineInfo&info);
+/*
+ * This version determines the extension method from the base expression type.
+ */
+inline NetExpr*pad_to_width(NetExpr*expr, unsigned wid, const LineInfo&info)
+{
+      return pad_to_width(expr, wid, expr->has_sign(), info);
+}
 
 /*
  * This function transforms an expression by either zero or sign extending
diff --git a/pad_to_width.cc b/pad_to_width.cc
index 85f8d74e4..32db9e6c4 100644
--- a/pad_to_width.cc
+++ b/pad_to_width.cc
@@ -24,33 +24,6 @@
 # include  "netmisc.h"
 
 
-/*
- * This function transforms an expression by padding the high bits
- * with V0 until the expression has the desired width. This may mean
- * not transforming the expression at all, if it is already wide
- * enough.
- */
-NetExpr*pad_to_width(NetExpr*expr, unsigned wid, const LineInfo&info)
-{
-      if (wid <= expr->expr_width())
-	    return expr;
-
-	/* If the expression is a const, then replace it with a wider
-	   const. This is a more efficient result. */
-      if (NetEConst*tmp = dynamic_cast<NetEConst*>(expr)) {
-	    verinum oval = pad_to_width(tmp->value(), wid);
-	    tmp = new NetEConst(oval);
-	    tmp->set_line(info);
-	    delete expr;
-	    return tmp;
-      }
-
-      NetESelect*tmp = new NetESelect(expr, 0, wid);
-      tmp->set_line(info);
-      tmp->cast_signed(expr->has_sign());
-      return tmp;
-}
-
 NetExpr*pad_to_width(NetExpr*expr, unsigned wid, bool signed_flag,
 		     const LineInfo&info)
 {