range_int_cst_p handling in extract_range_from_binary_expr_1

[Richard Sandiford]

extract_range_from_binary_expr_1 had:

      if (range_int_cst_p (&vr0)
          && range_int_cst_p (&vr1)
          && TYPE_OVERFLOW_WRAPS (expr_type))
        ...
      ...
      extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);

but extract_range_from_multiplicative_op_1 also requires range_int_cst_p.
I think we should bail out if either range isn't a constant.

This might only be theoretical with current sources, but it's needed
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): Don't call
        extract_range_from_multiplicative_op_1 if !range_int_cst_p.

Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c      2017-08-30 12:18:46.631541422 +0100
+++ gcc/tree-vrp.c      2017-09-20 13:04:20.397027078 +0100
@@ -2462,9 +2462,14 @@ extract_range_from_binary_expr_1 (value_
       signop sign = TYPE_SIGN (expr_type);
       unsigned int prec = TYPE_PRECISION (expr_type);
 
-      if (range_int_cst_p (&vr0)
-         && range_int_cst_p (&vr1)
-         && TYPE_OVERFLOW_WRAPS (expr_type))
+      if (!range_int_cst_p (&vr0)
+         || !range_int_cst_p (&vr1))
+       {
+         set_value_range_to_varying (vr);
+         return;
+       }
+
+      if (TYPE_OVERFLOW_WRAPS (expr_type))
        {
          typedef FIXED_WIDE_INT (WIDE_INT_MAX_PRECISION * 2) vrp_int;
          typedef generic_wide_int