re PR tree-optimization/71521 (Regression in GCC-7.0.0's optimizer)

2016-06-14  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/71521
	* tree-vrp.c (extract_range_from_binary_expr_1): Guard
	division int_const_binop against zero divisor.

	* gcc.dg/tree-ssa/vrp101.c: New testcase.

From-SVN: r237425

gcc/ChangeLog

+2016-06-14  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71521
+	* tree-vrp.c (extract_range_from_binary_expr_1): Guard
+	division int_const_binop against zero divisor.
+
 2016-06-13  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/i386.md (signbittf2): New expander.

gcc/testsuite/ChangeLog

+2016-06-14  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71521
+	* tree-vrp.c (extract_range_from_binary_expr_1): Guard
+	division int_const_binop against zero divisor.
+
 2016-06-13  Jakub Jelinek  <jakub@redhat.com>
 
 	PR sanitizer/71498

gcc/testsuite/gcc.dg/tree-ssa/vrp101.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+int x = 1;
+
+int main ()
+{
+  int t = (1/(1>=x))>>1;
+  if (t != 0) __builtin_abort();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "<bb 2>:\[\n\r \]*return 0;" "optimized" } } */

gcc/tree-vrp.c

@@ -2938,7 +2938,8 @@ extract_range_from_binary_expr_1 (value_range *vr,
 		     and divisor are available.  */
 		  if (vr1.type == VR_RANGE
 		      && !symbolic_range_p (&vr0)
-		      && !symbolic_range_p (&vr1))
+		      && !symbolic_range_p (&vr1)
+		      && compare_values (vr1.max, zero) != 0)
 		    min = int_const_binop (code, vr0.min, vr1.max);
 		  else
 		    min = zero;