tree.c (max_int_size_in_bytes): New function, inspired from code in function.c:assign_temp.

        * tree.c (max_int_size_in_bytes): New function, inspired from
        code in function.c:assign_temp.
        * tree.h (max_int_size_in_bytes): Declare.
        * function.c (assign_temp): Use it.
        * gimplify.c (create_tmp_var): Relax the assertions on the type
        properties, not mandating constant size any more.
        (force_constant_size): New static function.
        (gimple_add_tmp_var): Use it, forcing variable size to a
        constant upper bound if it is not constant on entry.

        * ada/misc.c (gnat_type_max_size): Look at TYPE_ADA_SIZE if we have
        not been able to get a constant upper bound from TYPE_SIZE_UNIT.

	* gnat.dg/varsize_temp.adb: New test.

From-SVN: r114938

1 files changed, 31 insertions, 4 deletions

diff --git a/gcc/ada/misc.c b/gcc/ada/misc.c
index 2f68e42..47206da 100644
--- a/gcc/ada/misc.c
+++ b/gcc/ada/misc.c
@@ -745,13 +745,40 @@ gnat_get_alias_set (tree type)
   return -1;
 }
 
-/* GNU_TYPE is a type.  Return its maxium size in bytes, if known.  */
+/* GNU_TYPE is a type.  Return its maxium size in bytes, if known,
+   as a constant when possible.  */
 
 static tree
-gnat_type_max_size (gnu_type)
-     tree gnu_type;
+gnat_type_max_size (tree gnu_type)
 {
-  return max_size (TYPE_SIZE_UNIT (gnu_type), true);
+  /* First see what we can get from TYPE_SIZE_UNIT, which might not be
+     constant even for simple expressions if it has already been gimplified
+     and replaced by a VAR_DECL.  */
+
+  tree max_unitsize = max_size (TYPE_SIZE_UNIT (gnu_type), true);
+
+  /* If we don't have a constant, see what we can get from TYPE_ADA_SIZE,
+     typically not gimplified.  */
+
+  if (!host_integerp (max_unitsize, 1)
+      && (TREE_CODE (gnu_type) == RECORD_TYPE
+	  || TREE_CODE (gnu_type) == UNION_TYPE
+	  || TREE_CODE (gnu_type) == QUAL_UNION_TYPE)
+      && TYPE_ADA_SIZE (gnu_type))
+    {
+      tree max_adasize = max_size (TYPE_ADA_SIZE (gnu_type), true);
+      
+      /* If we have succeded in finding a constant, round it up to the
+	 type's alignment and return the result in byte units.  */
+
+      if (host_integerp (max_adasize, 1))
+	max_unitsize
+	  = size_binop (CEIL_DIV_EXPR,
+			round_up (max_adasize, TYPE_ALIGN (gnu_type)),
+			bitsize_unit_node);
+    }
+
+  return max_unitsize;
 }
 
 /* GNU_TYPE is a type. Determine if it should be passed by reference by