[gomp4, 16/23] Keep address spaces on string type nodes

[Bernd Schmidt <bernds at codesourcery dot com>]

Another small patchlet to prepare for implicit address spaces. We'll
modify char_array_type_node etc. to have an address space for nvptx, and
we'll need to be careful to retain it in fix_string_type.

	gcc/c-family/
	* c-common.c (fix_string_type): Get the element type from the value's
	type if possible.

------------------------------------------------------------------------
Index: gcc/c-family/c-common.c
===================================================================
--- gcc/c-family/c-common.c.orig
+++ gcc/c-family/c-common.c
@@ -960,27 +960,28 @@ fix_string_type (tree value)
   int length = TREE_STRING_LENGTH (value);
   int nchars;
   tree e_type, i_type, a_type;
+  tree valtype = TREE_TYPE (value);
 
   /* Compute the number of elements, for the array type.  */
-  if (TREE_TYPE (value) == char_array_type_node || !TREE_TYPE (value))
+  if (valtype == char_array_type_node || !valtype)
     {
       nchars = length;
-      e_type = char_type_node;
+      e_type = valtype ? TREE_TYPE (valtype) : char_type_node;
     }
-  else if (TREE_TYPE (value) == char16_array_type_node)
+  else if (valtype == char16_array_type_node)
     {
       nchars = length / (TYPE_PRECISION (char16_type_node) / BITS_PER_UNIT);
-      e_type = char16_type_node;
+      e_type = TREE_TYPE (valtype);
     }
-  else if (TREE_TYPE (value) == char32_array_type_node)
+  else if (valtype == char32_array_type_node)
     {
       nchars = length / (TYPE_PRECISION (char32_type_node) / BITS_PER_UNIT);
-      e_type = char32_type_node;
+      e_type = TREE_TYPE (valtype);
     }
   else
     {
       nchars = length / (TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT);
-      e_type = wchar_type_node;
+      e_type = TREE_TYPE (valtype);
     }
 
   /* C89 2.2.4.1, C99 5.2.4.1 (Translation limits).  The analogous