diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index c2045f940fe..373ad298186 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,8 @@
+2012-01-24  Mike Stump  <mikestump@comcast.net>
+
+	* c-common.c (c_common_type_for_mode): Match signed/unsigned types
+	exactly.
+
 2012-01-18  Richard Guenther  <rguenther@suse.de>
 
 	* c-opts.c (c_common_post_options): Reset LTO flags if
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 013c71a6420..8dbf6cc2d75 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -3089,7 +3089,8 @@ c_common_type_for_mode (enum machine_mode mode, int unsignedp)
     }
 
   for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
-    if (TYPE_MODE (TREE_VALUE (t)) == mode)
+    if (TYPE_MODE (TREE_VALUE (t)) == mode
+	&& !!unsignedp == !!TYPE_UNSIGNED (TREE_VALUE (t)))
       return TREE_VALUE (t);
 
   return 0;