Add missing int_cst_rangeN checks to tree-vrp.c

[Richard Sandiford]

The BIT_AND_EXPR handling in extract_range_from_binary_expr_1
was using value_range_constant_singleton without first checking
whether the range was a constant.  The earlier handling was correctly
guarded:

          /* If either input range contains only non-negative values
             we can truncate the result range maximum to the respective
             maximum of the input range.  */
          if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
            wmax = wi::min (wmax, vr0.max, TYPE_SIGN (expr_type));
          if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
            wmax = wi::min (wmax, vr1.max, TYPE_SIGN (expr_type));

so this patch uses the same guards again.

Existing tests showed the need for this once polynomial constants
are added.

Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linus-gnu.
OK to install?

Richard


2017-09-20  Richard Sandiford  <richard.sandif...@linaro.org>
            Alan Hayward  <alan.hayw...@arm.com>
            David Sherwood  <david.sherw...@arm.com>

gcc/
        * tree-vrp.c (extract_range_from_binary_expr_1): Check
        int_cst_rangeN before calling value_range_constant_singleton (&vrN).

Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c      2017-09-20 13:04:29.932873038 +0100
+++ gcc/tree-vrp.c      2017-09-20 13:07:32.589667751 +0100
@@ -2930,9 +2930,11 @@ extract_range_from_binary_expr_1 (value_
                = wi::set_bit_in_zero (TYPE_PRECISION (expr_type) - 1,
                                       TYPE_PRECISION (expr_type));
              if (!TYPE_UNSIGNED (expr_type)
-                 && ((value_range_constant_singleton (&vr0)
+                 && ((int_cst_range0
+                      && value_range_constant_singleton (&vr0)
                       && !wi::cmps (vr0.min, sign_bit))
-                     || (value_range_constant_singleton (&vr1)
+                     || (int_cst_range1
+                         && value_range_constant_singleton (&vr1)
                          && !wi::cmps (vr1.min, sign_bit))))
                {
                  min = TYPE_MIN_VALUE (expr_type);