Use HOST_WIDE_INT for a param calculation (PR rtl-optimization/79574).

2017-02-17  Martin Liska  <mliska@suse.cz>

	PR rtl-optimization/79574
	* gcc.dg/pr79574.c: New test.
2017-02-17  Martin Liska  <mliska@suse.cz>

	PR rtl-optimization/79574
	* gcse.c (want_to_gcse_p): Prevent integer overflow.

From-SVN: r245531

gcc/ChangeLog

 2017-02-17  Martin Liska  <mliska@suse.cz>
 
+	PR rtl-optimization/79574
+	* gcse.c (want_to_gcse_p): Prevent integer overflow.
+
+2017-02-17  Martin Liska  <mliska@suse.cz>
+
 	PR tree-optimization/79529
 	* tree-ssa-loop-unswitch.c (is_maybe_undefined): Use
 	ssa_defined_default_def_p to handle cases which are implicitly

gcc/gcse.c

@@ -790,7 +790,7 @@ want_to_gcse_p (rtx x, machine_mode mode, int *max_distance_ptr)
 	/* PRE doesn't implement max_distance restriction.  */
 	{
 	  int cost;
-	  int max_distance;
+	  HOST_WIDE_INT max_distance;
 
 	  gcc_assert (!optimize_function_for_speed_p (cfun)
 		      && optimize_function_for_size_p (cfun));
@@ -798,7 +798,8 @@ want_to_gcse_p (rtx x, machine_mode mode, int *max_distance_ptr)
 
 	  if (cost < COSTS_N_INSNS (GCSE_UNRESTRICTED_COST))
 	    {
-	      max_distance = (GCSE_COST_DISTANCE_RATIO * cost) / 10;
+	      max_distance
+		= ((HOST_WIDE_INT)GCSE_COST_DISTANCE_RATIO * cost) / 10;
 	      if (max_distance == 0)
 		return 0;
 

gcc/testsuite/ChangeLog

+2017-02-17  Martin Liska  <mliska@suse.cz>
+
+	PR rtl-optimization/79574
+	* gcc.dg/pr79574.c: New test.
+
 2017-02-17  Marek Polacek  <polacek@redhat.com>
 
 	PR middle-end/79536

gcc/testsuite/gcc.dg/pr79574.c

+/* PR rtl-optimization/79574 */
+/* { dg-do compile } */
+/* { dg-options "-Os --param gcse-cost-distance-ratio=2147483647" } */
+
+void a (void)
+{
+  volatile int b;
+  for (;; b)
+    ;
+}