From 2532a696e445496c0bf2fcc67392ae66009dd0ba Mon Sep 17 00:00:00 2001
From: Tim Edwards <tim@opencircuitdesign.com>
Date: Thu, 18 Mar 2021 11:37:44 -0400
Subject: [PATCH] Correction from a recent commit;  complicated sets of "equiv"
 statement in a .ext file require that all aliases of a node name be rehashed
 after a node merge, or else node loops can occur.  Also prevented statements
 of the form "equiv A A" from being output in the .ext file, as they are
 useless.

---
 VERSION            |  2 +-
 extflat/EFbuild.c  | 18 +++++++++++++++---
 extract/ExtBasic.c |  8 ++++++--
 3 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/VERSION b/VERSION
index 5d5b8a8f..8d330699 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-8.3.142
+8.3.143
diff --git a/extflat/EFbuild.c b/extflat/EFbuild.c
index 97c71124..ef0cbb06 100644
--- a/extflat/EFbuild.c
+++ b/extflat/EFbuild.c
@@ -454,6 +454,8 @@ efBuildEquiv(def, nodeName1, nodeName2)
     nn1 = (EFNodeName *) HashGetValue(he1);
     nn2 = (EFNodeName *) HashGetValue(he2);
 
+    if (nn1 == nn2) return;	/* These nodes already merged */
+
     if (nn2 == (EFNodeName *) NULL)
     {
 	/* Create nodeName1 if it doesn't exist */
@@ -482,6 +484,10 @@ efBuildEquiv(def, nodeName1, nodeName2)
 	    return;		/* Repeated "equiv" statement */
 	if (nn1->efnn_node != nn2->efnn_node)
 	{
+	    struct efnode *node1 = nn1->efnn_node;
+	    struct efnode *node2 = nn2->efnn_node;
+    	    HashSearch hs;
+
 	    if (efWarn)
 		efReadError("Merged nodes %s and %s\n", nodeName1, nodeName2);
 	    efNodeMerge(&nn1->efnn_node, &nn2->efnn_node);
@@ -489,17 +495,23 @@ efBuildEquiv(def, nodeName1, nodeName2)
 	    else if (nn2->efnn_port > 0) nn1->efnn_port = nn2->efnn_port;
 
 	    /* If a node has been merged away, make sure that its name	*/
-	    /* points to the merged name's hash.			*/
+	    /* and all aliases point to the merged name's hash.		*/
 
 	    if (nn1->efnn_node == NULL)
 	    {
-    		HashSetValue(he1, (char *)nn2);
 		nn2->efnn_refc += nn1->efnn_refc + 1;
+    		HashStartSearch(&hs);
+    		while (he1 = HashNext(&def->def_nodes, &hs))
+		    if ((EFNodeName *)HashGetValue(he1) == nn1)
+			HashSetValue(he1, (char *)nn2);
 	    }
 	    else if (nn2->efnn_node == NULL)
 	    {
-    		HashSetValue(he2, (char *)nn1);
 		nn1->efnn_refc += nn2->efnn_refc + 1;
+    		HashStartSearch(&hs);
+    		while (he2 = HashNext(&def->def_nodes, &hs))
+		    if ((EFNodeName *)HashGetValue(he2) == nn2)
+			HashSetValue(he2, (char *)nn1);
 	    }
 	}
 	return;
diff --git a/extract/ExtBasic.c b/extract/ExtBasic.c
index 184d1be5..c5e0b1c3 100644
--- a/extract/ExtBasic.c
+++ b/extract/ExtBasic.c
@@ -727,13 +727,17 @@ extOutputNodes(nodeList, outFile)
 		fprintf(outFile, "\"\n");
 	    }
 
-	/* Output the alternate names for the node */
+	/* Output the alternate names for the node.  Avoid generating	*/
+	/* unnecessary "equiv A A" entries for labels on disconnected	*/
+	/* nets.							*/
+
 	for (ll = reg->nreg_labels; ll; ll = ll->ll_next)
 	    if (ll->ll_label->lab_text == text)
 	    {
 		for (ll = ll->ll_next; ll; ll = ll->ll_next)
 		     if (extLabType(ll->ll_label->lab_text, LABTYPE_NAME))
-			fprintf(outFile, "equiv \"%s\" \"%s\"\n",
+			if (strcmp(text, ll->ll_label->lab_text))
+			    fprintf(outFile, "equiv \"%s\" \"%s\"\n",
 					    text, ll->ll_label->lab_text);
 		break;
 	    }