decl.c (ceil_alignment): New function.

	* decl.c (ceil_alignment): New function.
	(gnat_to_gnu_entity): Use it to set the alignment on atomic types.
	(make_packable_type): Likewise.

From-SVN: r130373

gcc/ada/ChangeLog

+2007-11-23  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* decl.c (ceil_alignment): New function.
+	(gnat_to_gnu_entity): Use it to set the alignment on atomic types.
+	(make_packable_type): Likewise.
+
 2007-11-22  Olivier Hainque  <hainque@adacore.com>
 
 	* trans.c (gnat_to_gnu) <case N_Free_Statement>: Reformat lines

gcc/ada/decl.c

@@ -113,6 +113,7 @@ static tree validate_size (Uint, tree, Entity_Id, enum tree_code, bool, bool);
 static void set_rm_size (Uint, tree, Entity_Id);
 static tree make_type_from_size (tree, tree, bool);
 static unsigned int validate_alignment (Uint, Entity_Id, unsigned int);
+static unsigned int ceil_alignment (unsigned HOST_WIDE_INT);
 static void check_ok_for_atomic (tree, Entity_Id, bool);
 static int  compatible_signatures_p (tree ftype1, tree ftype2);
 
@@ -645,9 +646,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 	/* If this is an atomic object with no specified size and alignment,
 	   but where the size of the type is a constant, set the alignment to
-	   the lowest power of two greater than the size, or to the
-	   biggest meaningful alignment, whichever is smaller.  */
-
+	   the smallest not less than the size, or to the biggest meaningful
+	   alignment, whichever is smaller.  */
 	if (Is_Atomic (gnat_entity) && !gnu_size && align == 0
 	    && TREE_CODE (TYPE_SIZE (gnu_type)) == INTEGER_CST)
 	  {
@@ -656,10 +656,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 					  BIGGEST_ALIGNMENT))
 	      align = BIGGEST_ALIGNMENT;
 	    else
-	      align = ((unsigned int) 1
-		       << (floor_log2 (tree_low_cst
-				       (TYPE_SIZE (gnu_type), 1) - 1)
-			   + 1));
+	      align = ceil_alignment (tree_low_cst (TYPE_SIZE (gnu_type), 1));
 	  }
 
 	/* If the object is set to have atomic components, find the component
@@ -734,7 +731,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	     || (Is_Exported (gnat_entity)
 		 /* Exclude exported constants created by the compiler,
 		    which should boil down to static dispatch tables and
-		    make it possible to put them in read-only memory.  */
+		    make it possible to put them in read-only memory.  */
 		 && (Comes_From_Source (gnat_entity) || !const_flag))
 	     || Is_Imported (gnat_entity)
 	     || Present (Address_Clause (gnat_entity)))
@@ -2468,8 +2465,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	    = validate_alignment (Alignment (gnat_entity), gnat_entity, 0);
 	else if (Is_Atomic (gnat_entity))
 	  TYPE_ALIGN (gnu_type)
-	    = (esize >= BITS_PER_WORD ? BITS_PER_WORD
-	       : 1 << (floor_log2 (esize - 1) + 1));
+	    = esize >= BITS_PER_WORD ? BITS_PER_WORD : ceil_alignment (esize);
 	else
 	  TYPE_ALIGN (gnu_type) = 0;
 
@@ -5208,9 +5204,7 @@ make_packable_type (tree type)
       TYPE_SIZE_UNIT (new_type) = TYPE_SIZE_UNIT (type);
     }
 
-  TYPE_ALIGN (new_type)
-    = ((HOST_WIDE_INT) 1
-       << (floor_log2 (tree_low_cst (TYPE_SIZE (type), 1) - 1) + 1));
+  TYPE_ALIGN (new_type) = ceil_alignment (tree_low_cst (TYPE_SIZE (type), 1));
   TYPE_USER_ALIGN (new_type) = 1;
 
   /* Now copy the fields, keeping the position and size.  */
@@ -6783,6 +6777,14 @@ validate_alignment (Uint alignment, Entity_Id gnat_entity, unsigned int align)
 
   return align;
 }
+
+/* Return the smallest alignment not less than SIZE.  */
+
+static unsigned int
+ceil_alignment (unsigned HOST_WIDE_INT size)
+{
+  return (unsigned int) 1 << (floor_log2 (size - 1) + 1);
+}
 
 /* Verify that OBJECT, a type or decl, is something we can implement
    atomically.  If not, give an error for GNAT_ENTITY.  COMP_P is true