diff --git a/libyasm/inttree.c b/libyasm/inttree.c
index d6816afd..963276d3 100644
--- a/libyasm/inttree.c
+++ b/libyasm/inttree.c
@@ -58,8 +58,13 @@ ITN_create(long low, long high, void *data)
 {
     IntervalTreeNode *itn = yasm_xmalloc(sizeof(IntervalTreeNode));
     itn->data = data;
-    itn->low = low;
-    itn->high = high;
+    if (low < high) {
+	itn->low = low;
+	itn->high = high;
+    } else {
+	itn->low = high;
+	itn->high = low;
+    }
     itn->maxHigh = high;
     return itn;
 }
diff --git a/libyasm/section.c b/libyasm/section.c
index b751087d..5a401fad 100644
--- a/libyasm/section.c
+++ b/libyasm/section.c
@@ -966,6 +966,10 @@ optimize_term_expand(IntervalTreeNode *node, void *d)
     yasm_span *span = term->span;
     unsigned long len_diff = optd->len_diff;
 
+    /* Don't expand inactive spans */
+    if (!span->active)
+	return;
+
     /* Update term length */
     if (term->precbc2) {
 	if (term->precbc->bc_index > term->precbc2->bc_index)
@@ -1193,7 +1197,7 @@ yasm_object_optimize(yasm_object *object, yasm_arch *arch,
 
     /* Step 2 */
     while (!STAILQ_EMPTY(&optd.Q)) {
-	unsigned long orig_len, len_diff;
+	unsigned long orig_len;
 	span = STAILQ_FIRST(&optd.Q);
 	STAILQ_REMOVE_HEAD(&optd.Q, linkq);
 	orig_len = span->bc->len;
@@ -1215,8 +1219,8 @@ yasm_object_optimize(yasm_object *object, yasm_arch *arch,
 	    span->active = 0;
 	if (orig_len > span->bc->len)
 	    yasm_internal_error(N_("length decreased during an expansion"));
-	len_diff = span->bc->len - orig_len;
-	if (len_diff == 0)
+	optd.len_diff = span->bc->len - orig_len;
+	if (optd.len_diff == 0)
 	    continue;	/* didn't increase in size; unusual! */
 	IT_enumerate(optd.itree, (long)span->bc->bc_index,
 		     (long)span->bc->bc_index, &optd, optimize_term_expand);
diff --git a/modules/arch/x86/x86bc.c b/modules/arch/x86/x86bc.c
index 1f5be62b..6bdc594f 100644
--- a/modules/arch/x86/x86bc.c
+++ b/modules/arch/x86/x86bc.c
@@ -726,6 +726,9 @@ x86_bc_jmp_expand(yasm_bytecode *bc, int span, long old_val, long new_val,
 	return -1;
     }
 
+    if (jmp->op_sel == JMP_NEAR)
+	yasm_internal_error(N_("trying to expand an already-near jump"));
+
     /* Upgrade to a near jump */
     jmp->op_sel = JMP_NEAR;
     bc->len -= jmp->shortop.len + 1;