diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index 495dbf45d1d..e8ce2e6902c 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,9 @@
+2011-12-11  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc-interface/decl.c (gnat_to_gnu_entity) <object>: If there is an
+	alignment set on a renaming, assert that the renamed object is aligned
+	enough as to make it possible to honor it.
+
 2011-12-11  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc-interface/trans.c (gigi): Initialize the linemap earlier.
diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
index 12971a63038..aecbd76b983 100644
--- a/gcc/ada/gcc-interface/decl.c
+++ b/gcc/ada/gcc-interface/decl.c
@@ -1008,6 +1008,17 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 			saved = true;
 			annotate_object (gnat_entity, gnu_type, NULL_TREE,
 					 false, false);
+			/* This assertion will fail if the renamed object
+			   isn't aligned enough as to make it possible to
+			   honor the alignment set on the renaming.  */
+			if (align)
+			  {
+			    unsigned int renamed_align
+			      = DECL_P (gnu_decl)
+				? DECL_ALIGN (gnu_decl)
+				: TYPE_ALIGN (TREE_TYPE (gnu_decl));
+			    gcc_assert (renamed_align >= align);
+			  }
 			break;
 		      }