loop.c (remove_constant_addition): Avoid clobbering a shared CONST expression.

	* loop.c (remove_constant_addition): Avoid clobbering a shared
	CONST expression.

Co-Authored-By: Jan Hubicka <jh@suse.cz>

From-SVN: r49556

gcc/ChangeLog

+2002-02-06  Janis Johnson  <janis187@us.ibm.com>
+	    Jan Hubicka  <jh@suse.cz>
+
+	* loop.c (remove_constant_addition): Avoid clobbering a shared
+	CONST expression.
+
 2002-02-06  Ulrich Weigand  <uweigand@de.ibm.com>
 
 	* config.gcc (s390x-*-linux*): Add t-linux64 makefile fragment.

gcc/loop.c

@@ -3683,8 +3683,19 @@ remove_constant_addition (x)
   HOST_WIDE_INT addval = 0;
   rtx exp = *x;
 
+  /* Avoid clobbering a shared CONST expression.  */
   if (GET_CODE (exp) == CONST)
-    exp = XEXP (exp, 0);
+    {
+      if (GET_CODE (XEXP (exp, 0)) == PLUS
+	  && GET_CODE (XEXP (XEXP (exp, 0), 0)) == SYMBOL_REF
+	  && GET_CODE (XEXP (XEXP (exp, 0), 1)) == CONST_INT)
+	{
+	  *x = XEXP (XEXP (exp, 0), 0);
+	  return INTVAL (XEXP (XEXP (exp, 0), 1));
+	}
+      return 0;
+    }
+
   if (GET_CODE (exp) == CONST_INT)
     {
       addval = INTVAL (exp);