Check for overflow in tree-switch-conversion (PR middle-end/90478).

2019-05-15  Martin Liska  <mliska@suse.cz>

	PR middle-end/90478
	* tree-switch-conversion.c (jump_table_cluster::can_be_handled):
	Check for overflow.
2019-05-15  Martin Liska  <mliska@suse.cz>

	PR middle-end/90478
	* gcc.dg/tree-ssa/pr90478-2.c: New test.
	* gcc.dg/tree-ssa/pr90478.c: New test.

From-SVN: r271210

gcc/ChangeLog

+2019-05-15  Martin Liska  <mliska@suse.cz>
+
+	PR middle-end/90478
+	* tree-switch-conversion.c (jump_table_cluster::can_be_handled):
+	Check for overflow.
+
 2019-05-15  Richard Biener  <rguenther@suse.de>
 
 	* tree-into-ssa.c (pass_build_ssa::execute): Run

gcc/testsuite/ChangeLog

+2019-05-15  Martin Liska  <mliska@suse.cz>
+
+	PR middle-end/90478
+	* gcc.dg/tree-ssa/pr90478-2.c: New test.
+	* gcc.dg/tree-ssa/pr90478.c: New test.
+
 2019-05-15  Richard Biener  <rguenther@suse.de>
 
 	* gcc.dg/gimplefe-40.c: Amend.

gcc/testsuite/gcc.dg/tree-ssa/pr90478-2.c

+/* { dg-do compile } */
+/* { dg-options "-Os --param jump-table-max-growth-ratio-for-size=2147483647" } */
+
+long
+foo (long x, long y)
+{
+  x = x & y;
+  switch (y)
+    {
+    case 63L: x >>= 0; break;
+    case 4032L: x >>= 6; break;
+    case 258048L: x >>= 12; break;
+    case 16515072L: x >>= 18; break;
+    default: __builtin_unreachable ();
+    }
+  return x;
+}

gcc/testsuite/gcc.dg/tree-ssa/pr90478.c

+/* { dg-do compile } */
+
+typedef struct {
+  long a;
+} c;
+
+void e();
+
+void d() {
+  c *b;
+  switch (b->a)
+  case 8:
+  case 2:
+  case 2057594037927936:
+  case 0:
+  case 4611686018427387904:
+    e();
+}

gcc/tree-switch-conversion.c

@@ -1284,7 +1284,11 @@ jump_table_cluster::can_be_handled (const vec<cluster *> &clusters,
       comparison_count += sc->m_range_p ? 2 : 1;
     }
 
-  return 100 * range <= max_ratio * comparison_count;
+  unsigned HOST_WIDE_INT lhs = 100 * range;
+  if (lhs < range)
+    return false;
+
+  return lhs <= max_ratio * comparison_count;
 }
 
 /* Return true if cluster starting at START and ending at END (inclusive)