wide-int-range.h (wide_int_range_shift_undefined_p): Adjust to use sign as argument.

	* wide-int-range.h (wide_int_range_shift_undefined_p): Adjust to
	use sign as argument.
	* tree-vrp.c (extract_range_from_binary_expr_1): Pass sign to
	wide_int_range_shift_undefined_p.

From-SVN: r265237

gcc/ChangeLog

+2018-10-17  Aldy Hernandez  <aldyh@redhat.com>
+
+	* wide-int-range.h (wide_int_range_shift_undefined_p): Adjust to
+	use sign as argument.
+	* tree-vrp.c (extract_range_from_binary_expr_1): Pass sign to
+	wide_int_range_shift_undefined_p.
+
 2018-10-16  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* config/aarch64/aarch64.md (despeculate_copy<ALLI_TI:mode>):

gcc/tree-vrp.c

@@ -1521,7 +1521,8 @@ extract_range_from_binary_expr_1 (value_range *vr,
 	   || code == LSHIFT_EXPR)
     {
       if (range_int_cst_p (&vr1)
-	  && !wide_int_range_shift_undefined_p (prec,
+	  && !wide_int_range_shift_undefined_p (TYPE_SIGN (TREE_TYPE (vr1.min)),
+						prec,
 						wi::to_wide (vr1.min),
 						wi::to_wide (vr1.max)))
 	{

gcc/wide-int-range.h

@@ -128,10 +128,11 @@ extern bool wide_int_range_div (wide_int &wmin, wide_int &wmax,
 				bool &extra_range_p,
 				wide_int &extra_min, wide_int &extra_max);
 
-/* Return TRUE if shifting by range [MIN, MAX] is undefined behavior.  */
+/* Return TRUE if shifting by range [MIN, MAX] is undefined behavior,
+   interpreting MIN and MAX according to SIGN.  */
 
 inline bool
-wide_int_range_shift_undefined_p (unsigned prec,
+wide_int_range_shift_undefined_p (signop sign, unsigned prec,
 				  const wide_int &min, const wide_int &max)
 {
   /* ?? Note: The original comment said this only applied to
@@ -142,7 +143,7 @@ wide_int_range_shift_undefined_p (unsigned prec,
      behavior from the shift operation.  We cannot even trust
      SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
      shifts, and the operation at the tree level may be widened.  */
-  return wi::sign_mask (min) || wi::ge_p (max, prec, UNSIGNED);
+  return wi::lt_p (min, 0, sign) || wi::ge_p (max, prec, sign);
 }
 
 /* Calculate MIN/MAX_EXPR of two ranges and store the result in [MIN, MAX].  */