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, 33 insertions, 0 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index 2df2f7b..cbf4cc5 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -1733,6 +1733,39 @@ int_size_in_bytes (tree type)
 
   return TREE_INT_CST_LOW (t);
 }
+
+/* Return the maximum size of TYPE (in bytes) as a wide integer
+   or return -1 if the size can vary or is larger than an integer.  */
+
+HOST_WIDE_INT
+max_int_size_in_bytes (tree type)
+{
+  HOST_WIDE_INT size = -1;
+  tree size_tree;
+
+  /* If this is an array type, check for a possible MAX_SIZE attached.  */
+
+  if (TREE_CODE (type) == ARRAY_TYPE)
+    {
+      size_tree = TYPE_ARRAY_MAX_SIZE (type);
+
+      if (size_tree && host_integerp (size_tree, 1))
+	size = tree_low_cst (size_tree, 1);
+    }
+
+  /* If we still haven't been able to get a size, see if the language
+     can compute a maximum size.  */
+
+  if (size == -1)
+    {
+      size_tree = lang_hooks.types.max_size (type);
+
+      if (size_tree && host_integerp (size_tree, 1))
+	size = tree_low_cst (size_tree, 1);
+    }
+
+  return size;
+}
 
 /* Return the bit position of FIELD, in bits from the start of the record.
    This is a tree of type bitsizetype.  */