diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1520949961e..19e9f543a51 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2000-09-12  Jim Wilson  <wilson@cygnus.com>
+
+	* ifcvt.c (noce_process_if_block): If A and B are the same, and no
+	else block, and X has side-effects, then fail.
+
 2000-09-12  Greg McGary  <greg@mcgary.org>
 
 	* config/mips/mips-protos.h
diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index 901bd42b483..3ca0e6ccc65 100644
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -1247,6 +1247,11 @@ noce_process_if_block (test_bb, then_bb, else_bb, join_bb)
 	  reorder_insns (insn_b, insn_b, PREV_INSN (if_info.cond_earliest));
 	  insn_b = NULL_RTX;
 	}
+      /* If we have "x = b; if (...) x = a;", and x has side-effects, then
+	 x must be executed twice.  */
+      else if (insn_b && side_effects_p (orig_x))
+	return FALSE;
+	
       x = orig_x;
       goto success;
     }