tree.h (TREE_OVERFLOW): Make this flag/predicate specific to constant nodes, i.e.

	* tree.h (TREE_OVERFLOW): Make this flag/predicate specific to
	constant nodes, i.e. INTEGER_CST, REAL_CST, etc...
	* tree-vrp.c (compare_values): Only check TREE_OVERFLOW for
	integer constant comparisons.

ada/
	* utils.c (max_size): Only test for TREE_OVERFLOW on INTEGER_CST
	nodes.

From-SVN: r107870