re PR c/8639 (simple integer arithmetic expression broken)

        PR c/8639
        * fold-const.c (extract_muldiv): Don't propagate division unless
        both arguments are multiples of C.
	* gcc.c-torture/execute/20021119-1.c: New.

From-SVN: r59466

gcc/ChangeLog

+2002-11-25  Christian Ehrhardt  <ehrhardt@mathematik.uni-ulm.de>
+
+	PR c/8639
+	* fold-const.c (extract_muldiv): Don't propagate division unless
+	both arguments are multiples of C.
+
 2002-11-25  Andrew Haley  <aph@redhat.com>
 
         * libgcc-std.ver (_Unwind_Find_Enclosing_Function): Add.

gcc/fold-const.c

@@ -4178,10 +4178,10 @@ extract_muldiv (t, c, code, wide_type)
       t2 = extract_muldiv (op1, c, code, wide_type);
       if (t1 != 0 && t2 != 0
 	  && (code == MULT_EXPR
-	      /* If not multiplication, we can only do this if either operand
-		 is divisible by c.  */
-	      || multiple_of_p (ctype, op0, c)
-	      || multiple_of_p (ctype, op1, c)))
+	      /* If not multiplication, we can only do this if both operands
+		 are divisible by c.  */
+	      || (multiple_of_p (ctype, op0, c)
+	          && multiple_of_p (ctype, op1, c))))
 	return fold (build (tcode, ctype, convert (ctype, t1),
 			    convert (ctype, t2)));
 

gcc/testsuite/gcc.c-torture/execute/20021119-1.c

+/* PR 8639.  */
+
+extern void abort(void);
+
+int foo (int i)
+{
+  int r;
+  r = (80 - 4 * i) / 20;
+  return r;
+}
+    
+int main ()
+{
+  if (foo (1) != 3)
+    abort ();
+  return 0;
+}