re PR middle-end/54120 (FAIL: gfortran.fortran-torture/execute/random_2.f90 execution)

	PR tree-optimization/54120
	* tree-vrp.c (range_fits_type_p): Don't allow
	src_precision < precision from signed vr to unsigned_p
	if vr->min or vr->max is negative.
	(simplify_float_conversion_using_ranges): Test can_float_p
	against CODE_FOR_nothing.

From-SVN: r195007

gcc/ChangeLog

 2013-01-08  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/54120
+	* tree-vrp.c (range_fits_type_p): Don't allow
+	src_precision < precision from signed vr to unsigned_p
+	if vr->min or vr->max is negative.
+	(simplify_float_conversion_using_ranges): Test can_float_p
+	against CODE_FOR_nothing.
+
+2013-01-08  Jakub Jelinek  <jakub@redhat.com>
 	    Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/55851

gcc/tree-vrp.c

 /* Support routines for Value Range Propagation (VRP).
-   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
+   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
    Free Software Foundation, Inc.
    Contributed by Diego Novillo <dnovillo@redhat.com>.
 
@@ -8753,9 +8753,11 @@ range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
       && !POINTER_TYPE_P (src_type))
     return false;
 
-  /* An extension is always fine, so is an identity transform.  */
+  /* An extension is fine unless VR is signed and unsigned_p,
+     and so is an identity transform.  */
   src_precision = TYPE_PRECISION (TREE_TYPE (vr->min));
-  if (src_precision < precision
+  if ((src_precision < precision
+       && !(unsigned_p && !TYPE_UNSIGNED (src_type)))
       || (src_precision == precision
 	  && TYPE_UNSIGNED (src_type) == unsigned_p))
     return true;
@@ -8813,7 +8815,7 @@ simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
     mode = TYPE_MODE (TREE_TYPE (rhs1));
   /* If we can do the conversion in the current input mode do nothing.  */
   else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
-			TYPE_UNSIGNED (TREE_TYPE (rhs1))))
+			TYPE_UNSIGNED (TREE_TYPE (rhs1))) != CODE_FOR_nothing)
     return false;
   /* Otherwise search for a mode we can use, starting from the narrowest
      integer mode available.  */