diff --git a/base/flatten.c b/base/flatten.c
index 11e2cf1..567862c 100644
--- a/base/flatten.c
+++ b/base/flatten.c
@@ -1421,11 +1421,27 @@ typedef struct ecomplist {
     ECompListPtr next;
 } ECompList;
 
+/*----------------------------------------------------------------------*/
+/* Determine if a cell contains at least one device or subcircuit	*/
+/*----------------------------------------------------------------------*/
+
+int
+HasContents(struct nlist *tc)
+{
+    struct objlist *ob;
+
+    for (ob = tc->cell; ob; ob = ob->next)
+	if (ob->type == FIRSTPIN)
+	    return TRUE;
+
+    return FALSE;
+}
+
 /*------------------------------------------------------*/
 /* Survey the contents of a cell and sort into a hash	*/
 /*------------------------------------------------------*/
 
-int
+void
 SurveyCell(struct nlist *tc, struct hashdict *compdict, int file1, int file2, int which)
 {
     struct objlist *ob;
@@ -1433,12 +1449,10 @@ SurveyCell(struct nlist *tc, struct hashdict *compdict, int file1, int file2, in
     ECompare *ecomp, *qcomp, *ncomp;
     int file = (which == 0) ? file1 : file2;
     int ofile = (which == 0) ? file2 : file1;
-    int retval = FALSE;
     char *dstr;
 
     for (ob = tc->cell; ob; ob = ob->next) {
 	if (ob->type == FIRSTPIN) {
-	    retval = TRUE;	/* Cell has at least one device or subcircuit */
 	    tsub = LookupCellFile(ob->model.class, file);
 	    if (tsub->flags & CELL_DUPLICATE) {
 	       // Always register a duplicate under the original name
@@ -1492,7 +1506,6 @@ SurveyCell(struct nlist *tc, struct hashdict *compdict, int file1, int file2, in
 	    if (dstr) *dstr = '[';
 	}
     }
-    return retval;
 }
 
 /*------------------------------------------------------*/
@@ -1540,28 +1553,10 @@ PrematchLists(char *name1, int file1, char *name2, int file2)
     listX0 = list0X = NULL;
 
     // Gather information about instances of cell "name1"
-    hascontents1 = SurveyCell(tc1, &compdict, file1, file2, 0);
+    SurveyCell(tc1, &compdict, file1, file2, 0);
 
     // Gather information about instances of cell "name2"
-    hascontents2 = SurveyCell(tc2, &compdict, file1, file2, 1);
-
-    // If one cell has no contents, then flattening the other
-    // isn't going to improve anything, so stop here.
-
-    if (!hascontents1 && !hascontents2 && (tc1->flags & CELL_PLACEHOLDER)
-		&& (tc2->flags & CELL_PLACEHOLDER)) {
-        goto done;
-    }
-    else if (hascontents1 && !hascontents2 && (tc2->flags & CELL_PLACEHOLDER)) {
-	Fprintf(stdout, "Circuit 2 cell %s is a black box; will not flatten "
-			"Circuit 1\n", name2);
-	goto done;
-    }
-    else if (hascontents2 && !hascontents1 && (tc1->flags & CELL_PLACEHOLDER)) {
-	Fprintf(stdout, "Circuit 1 cell %s is a black box; will not flatten "
-			"Circuit 2\n", name1);
-	goto done;
-    }
+    SurveyCell(tc2, &compdict, file1, file2, 1);
 
     // Find all instances of one cell that have fewer in
     // the compared circuit.  Check whether subcircuits
diff --git a/base/flatten.h b/base/flatten.h
index d259998..64f306b 100644
--- a/base/flatten.h
+++ b/base/flatten.h
@@ -3,5 +3,6 @@
 
 extern int UniquePins(char *name, int filenum);
 extern void flattenCell(char *name, int file);
+extern int HasContents(struct nlist *);
 
 #endif /* _FLATTEN_H */
diff --git a/base/netcmp.h b/base/netcmp.h
index da7a722..df77fdd 100644
--- a/base/netcmp.h
+++ b/base/netcmp.h
@@ -46,6 +46,7 @@ extern int  CreateCompareQueue(char *, int, char *, int);
 extern int  GetCompareQueueTop(char **, int *, char **, int *);
 extern int  PeekCompareQueueTop(char **, int *, char **, int *);
 extern void RemoveCompareQueue();
+extern int FlattenUnmatched(struct nlist *, char *, int, int);
 
 extern void PrintIllegalClasses();
 extern void PrintIllegalNodeClasses();
diff --git a/tcltk/tclnetgen.c b/tcltk/tclnetgen.c
index 6cb69dc..a75fa14 100644
--- a/tcltk/tclnetgen.c
+++ b/tcltk/tclnetgen.c
@@ -2095,8 +2095,9 @@ _netcmp_compare(ClientData clientData,
    int dohierarchy = FALSE;
    int assignonly = FALSE;
    int argstart = 1, qresult, llen, result;
+   int hascontents1, hascontents2;
    struct Correspond *nextcomp;
-   struct nlist *tp;
+   struct nlist *tp1 = NULL, *tp2 = NULL;
    Tcl_Obj *flist = NULL;
 
    if (objc > 1) {
@@ -2139,24 +2140,24 @@ _netcmp_compare(ClientData clientData,
       }
       else if ((objc - argstart) == 2) {
 
-	 result = CommonParseCell(interp, objv[argstart], &tp, &fnum1);
+	 result = CommonParseCell(interp, objv[argstart], &tp1, &fnum1);
          if (result != TCL_OK) return TCL_ERROR;
 	 else if (fnum1 == -1) {
 	    Tcl_SetResult(interp, "Cannot use wildcard with compare command.\n",
 			NULL);
 	    return TCL_ERROR;
 	 }
-         name1 = tp->name;
+         name1 = tp1->name;
 	 argstart++;
 
-	 result = CommonParseCell(interp, objv[argstart], &tp, &fnum2);
+	 result = CommonParseCell(interp, objv[argstart], &tp2, &fnum2);
          if (result != TCL_OK) return TCL_ERROR;
 	 else if (fnum2 == -1) {
 	    Tcl_SetResult(interp, "Cannot use wildcard with compare command.\n",
 			NULL);
 	    return TCL_ERROR;
 	 }
-         name2 = tp->name;
+         name2 = tp2->name;
 
          if (dohierarchy) {
 	    RemoveCompareQueue();
@@ -2195,11 +2196,33 @@ _netcmp_compare(ClientData clientData,
       ConvertGlobals(name2, fnum2);
    }
 
+   if (tp1 == NULL) tp1 = LookupCellFile(name1, fnum1);
+   if (tp2 == NULL) tp2 = LookupCellFile(name2, fnum2);
+
    CreateTwoLists(name1, fnum1, name2, fnum2, dolist);
-   while (PrematchLists(name1, fnum1, name2, fnum2) > 0) {
-      Fprintf(stdout, "Making another compare attempt.\n");
-      Printf("Flattened mismatched instances and attempting compare again.\n");
-      CreateTwoLists(name1, fnum1, name2, fnum2, dolist);
+
+   hascontents1 = HasContents(tp1);
+   hascontents2 = HasContents(tp2);
+
+   if (hascontents1 && !hascontents2 && (tp2->flags & CELL_PLACEHOLDER)) {
+       Fprintf(stdout, "Circuit 2 cell %s is a black box; will not flatten "
+                        "Circuit 1\n", name2);
+   }
+   else if (hascontents2 && !hascontents1 && (tp1->flags & CELL_PLACEHOLDER)) {
+       Fprintf(stdout, "Circuit 1 cell %s is a black box; will not flatten "
+                        "Circuit 2\n", name1);
+   }
+   else if (hascontents1 || hascontents2) {
+       FlattenUnmatched(tp1, name1, 1, 0);
+       FlattenUnmatched(tp2, name2, 1, 0);
+
+       while (PrematchLists(name1, fnum1, name2, fnum2) > 0) {
+          Fprintf(stdout, "Making another compare attempt.\n");
+          Printf("Flattened mismatched instances and attempting compare again.\n");
+          CreateTwoLists(name1, fnum1, name2, fnum2, dolist);
+          FlattenUnmatched(tp1, name1, 0, 0);
+          FlattenUnmatched(tp2, name2, 0, 0);
+       }
    }
 
    // Return the names of the two cells being compared, if doing "compare