Tighten tree-ssa-ccp.c:get_value_for_expr condition

bit_value_unop and bit_value_binop require constant values
to be INTEGER_CSTs:

  gcc_assert ((rval.lattice_val == CONSTANT
               && TREE_CODE (rval.value) == INTEGER_CST)
              || wi::sext (rval.mask, TYPE_PRECISION (TREE_TYPE (rhs))) == -1);

However, when deciding whether to record a constant value,
the for_bits_p handling in get_value_for_expr used a negative
test for ADDR_EXPR:

  else if (is_gimple_min_invariant (expr)
           && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR))

This patch uses a positive test for INTEGER_CST instead.

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

2017-09-21  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* tree-ssa-ccp.c (get_value_for_expr): Use a positive test for
	INTEGER_CST rather than a negative test for ADDR_EXPR.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r253056

gcc/ChangeLog

@@ -2,6 +2,13 @@
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>
 
+	* tree-ssa-ccp.c (get_value_for_expr): Use a positive test for
+	INTEGER_CST rather than a negative test for ADDR_EXPR.
+
+2017-09-21  Richard Sandiford  <richard.sandiford@linaro.org>
+	    Alan Hayward  <alan.hayward@arm.com>
+	    David Sherwood  <david.sherwood@arm.com>
+
 	* tree-vrp.c (extract_range_from_binary_expr_1): Check
 	int_cst_rangeN before calling value_range_constant_singleton (&vrN).
 

gcc/tree-ssa-ccp.c

@@ -617,7 +617,7 @@ get_value_for_expr (tree expr, bool for_bits_p)
 	}
     }
   else if (is_gimple_min_invariant (expr)
-	   && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR))
+	   && (!for_bits_p || TREE_CODE (expr) == INTEGER_CST))
     {
       val.lattice_val = CONSTANT;
       val.value = expr;