re PR rtl-optimization/13318 (ICE: floating point exception in the loop optimizer)

	PR optimization/13318
	* loop.c (express_from): Protect integer division from overflow.

From-SVN: r74387

gcc/ChangeLog

 2003-12-07  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
+	PR optimization/13318
+	* loop.c (express_from): Protect integer division from overflow.
+
+2003-12-07  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
 	PR optimization/13060
 	* function.c (fixup_var_refs_1) [SUBREG]: Recognize even if a
 	replacement already exists.  Fix again the whole insn if that fails.

gcc/loop.c

@@ -7196,6 +7196,9 @@ express_from (struct induction *g1, struct induction *g2)
       && GET_CODE (g2->mult_val) == CONST_INT)
     {
       if (g1->mult_val == const0_rtx
+	  || (g1->mult_val == constm1_rtx
+	      && INTVAL (g2->mult_val)
+		 == (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT - 1))
 	  || INTVAL (g2->mult_val) % INTVAL (g1->mult_val) != 0)
 	return NULL_RTX;
       mult = GEN_INT (INTVAL (g2->mult_val) / INTVAL (g1->mult_val));

gcc/testsuite/ChangeLog

+2003-12-07  Wolfgang Bangerth  <bangerth@dealii.org>
+
+	* gcc.dg/overflow-1.c: New test.
+
 2003-12-07  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
 	* g77.f-torture/compile/13060.f: New test.

gcc/testsuite/gcc.dg/overflow-1.c

+/* PR optimization/13318 */
+/* Origin: <bremner@unb.ca> */
+/* Reduced testcase: Wolfgang Bangerth <bangerth@dealii.org> */
+
+/* Verify that the big multiplier doesn't cause an integer
+   overflow in the loop optimizer.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+struct S {
+  int key;
+  int rnext,rprev;
+};
+ 
+void foo(struct S* H)
+{
+  int i, k;
+  for (i=0; i<2; i++){
+    struct S* cell=H+k;
+    cell->key=i*(0xffffffffUL/2);
+    cell->rnext=k+(1-i);
+    cell->rprev=k+(1-i);
+  }
+}