Disallow setting of NANs in frange setter unless setting trees.

frange::set() is confusing in that we can set a NAN by specifying a
bound of +-NAN, even though we tecnically disallow NANs in the setter
because the kind can never be VR_NAN.  This is a wart for
get_tree_range(), which builds a range out of a tree from the source,
to work correctly.  It's ugly, and it showed its limitation while
implementing LTO streaming of ranges.

This patch disallows passing NAN bounds in frange::set() and fixes
get_tree_range.

gcc/ChangeLog:

	* value-query.cc (range_query::get_tree_range): Set NAN directly
	if necessary.
	* value-range.cc (frange::set): Assert that bounds are not NAN.

1 files changed, 10 insertions, 3 deletions

diff --git a/gcc/value-query.cc b/gcc/value-query.cc
index 43297f1..a84f164 100644
--- a/gcc/value-query.cc
+++ b/gcc/value-query.cc
@@ -189,9 +189,16 @@ range_query::get_tree_range (vrange &r, tree expr, gimple *stmt)
       {
 	frange &f = as_a <frange> (r);
 	REAL_VALUE_TYPE *rv = TREE_REAL_CST_PTR (expr);
-	f.set (TREE_TYPE (expr), *rv, *rv);
-	if (!real_isnan (rv))
-	  f.clear_nan ();
+	if (real_isnan (rv))
+	  {
+	    bool sign = real_isneg (rv);
+	    f.set_nan (TREE_TYPE (expr), sign);
+	  }
+	else
+	  {
+	    nan_state nan (false);
+	    f.set (TREE_TYPE (expr), *rv, *rv, nan);
+	  }
 	return true;
       }