Normalize unsigned ~[0,0] into [1,MAX].

From-SVN: r276949

gcc/ChangeLog

+2019-10-14  Aldy Hernandez  <aldyh@redhat.com>
+
+	* tree-vrp.c (value_range_base::set): Normalize unsigned ~[0,0]
+	into [1,MAX].
+	* tree-vrp.h (value_range_base::nonzero_p): Adjust for unsigned
+	non-zero being represented as [1,MAX].
+
 2019-10-14  Xiong Hu Luo  <luoxhu@linux.ibm.com>
 
 	* tree-sra.c (dump_access): Add missing braces.

gcc/testsuite/ChangeLog

+2019-10-14  Aldy Hernandez  <aldyh@redhat.com>
+
+	* gcc.dg/tree-ssa/evrp4.c: Adjust for unsigned non-zero being
+	[1,MAX].
+
 2019-10-13  Iain Sandoe  <iain@sandoe.co.uk>
 
 	* gcc.target/i386/indirect-thunk-1.c: Allow 'l' or 'L' in

gcc/testsuite/gcc.dg/tree-ssa/evrp4.c

@@ -17,4 +17,4 @@ int bar (struct st *s)
   foo (&s->a);
 }
 
-/* { dg-final { scan-tree-dump "\~\\\[0B, 0B\\\]" "evrp" } } */
+/* { dg-final { scan-tree-dump "\\\[1B, -1B\\\]" "evrp" } } */

gcc/tree-vrp.c

@@ -800,13 +800,13 @@ value_range_base::set (enum value_range_kind kind, tree min, tree max)
 	  kind = VR_RANGE;
 	}
       else if (is_min
-	       /* As a special exception preserve non-null ranges.  */
-	       && !(TYPE_UNSIGNED (TREE_TYPE (min))
-		    && integer_zerop (max)))
+	       /* Allow non-zero pointers to be normalized to [1,MAX].  */
+	       || (POINTER_TYPE_P (TREE_TYPE (min))
+		   && integer_zerop (min)))
         {
 	  tree one = build_int_cst (TREE_TYPE (max), 1);
 	  min = int_const_binop (PLUS_EXPR, max, one);
-	  max = vrp_val_max (TREE_TYPE (max));
+	  max = vrp_val_max (TREE_TYPE (max), true);
 	  kind = VR_RANGE;
         }
       else if (is_max)

gcc/tree-vrp.h

@@ -245,16 +245,6 @@ value_range_base::zero_p () const
 	  && integer_zerop (m_max));
 }
 
-/* Return TRUE if range is nonzero.  */
-
-inline bool
-value_range_base::nonzero_p () const
-{
-  return (m_kind == VR_ANTI_RANGE
-	  && integer_zerop (m_min)
-	  && integer_zerop (m_max));
-}
-
 extern void dump_value_range (FILE *, const value_range *);
 extern void dump_value_range (FILE *, const value_range_base *);
 
@@ -322,6 +312,23 @@ extern tree get_single_symbol (tree, bool *, tree *);
 extern void maybe_set_nonzero_bits (edge, tree);
 extern value_range_kind determine_value_range (tree, wide_int *, wide_int *);
 
+/* Return TRUE if range is nonzero.  */
+
+inline bool
+value_range_base::nonzero_p () const
+{
+  if (m_kind == VR_ANTI_RANGE
+      && !TYPE_UNSIGNED (type ())
+      && integer_zerop (m_min)
+      && integer_zerop (m_max))
+    return true;
+
+  return (m_kind == VR_RANGE
+	  && TYPE_UNSIGNED (type ())
+	  && integer_onep (m_min)
+	  && vrp_val_is_max (m_max, true));
+}
+
 /* Return TRUE if *VR includes the value zero.  */
 
 inline bool