diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d528a79dd62..0316406c4c1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+Thu May  6 20:34:00 1999  Mark Mitchell  <mark@codesourcery.com>
+
+	* resource.c (mark_referenced_resources): Make volatil
+	monotonically increasing.
+	(mark_set_resources): Likewise.
+
 Thu May  6 20:02:33 1999  Fred Fish  <fnf@be.com>
 
 	* rs6000/xm-beos.h (HAVE_VPRINTF): Don't redefine if already defined.
diff --git a/gcc/resource.c b/gcc/resource.c
index bc214a3dc23..ddf7df5d707 100644
--- a/gcc/resource.c
+++ b/gcc/resource.c
@@ -221,7 +221,7 @@ mark_referenced_resources (x, res, include_delayed_effects)
 	res->unch_memory = 1;
       else
 	res->memory = 1;
-      res->volatil = MEM_VOLATILE_P (x);
+      res->volatil |= MEM_VOLATILE_P (x);
 
       /* Mark registers used to access memory.  */
       mark_referenced_resources (XEXP (x, 0), res, 0);
@@ -242,7 +242,7 @@ mark_referenced_resources (x, res, include_delayed_effects)
       break;
 
     case ASM_OPERANDS:
-      res->volatil = MEM_VOLATILE_P (x);
+      res->volatil |= MEM_VOLATILE_P (x);
 
       /* For all ASM_OPERANDS, we must traverse the vector of input operands.
 	 We can not just fall through here since then we would be confused
@@ -710,8 +710,8 @@ mark_set_resources (x, res, in_dest, include_delayed_effects)
       if (in_dest)
 	{
 	  res->memory = 1;
-	  res->unch_memory = RTX_UNCHANGING_P (x);
-	  res->volatil = MEM_VOLATILE_P (x);
+	  res->unch_memory |= RTX_UNCHANGING_P (x);
+	  res->volatil |= MEM_VOLATILE_P (x);
 	}
 
       mark_set_resources (XEXP (x, 0), res, 0, 0);
@@ -750,7 +750,7 @@ mark_set_resources (x, res, in_dest, include_delayed_effects)
       break;
 
     case ASM_OPERANDS:
-      res->volatil = MEM_VOLATILE_P (x);
+      res->volatil |= MEM_VOLATILE_P (x);
 
       /* For all ASM_OPERANDS, we must traverse the vector of input operands.
 	 We can not just fall through here since then we would be confused