Index: gcc/c-common.c
===================================================================
--- gcc/c-common.c	(revision 124741)
+++ gcc/c-common.c	(working copy)
@@ -2065,10 +2065,37 @@
 tree
 c_common_signed_or_unsigned_type (int unsignedp, tree type)
 {
+  tree type1;
   if (!INTEGRAL_TYPE_P (type)
       || TYPE_UNSIGNED (type) == unsignedp)
     return type;
 
+  type1 = TYPE_MAIN_VARIANT (type);
+  if (type1 == signed_char_type_node || type1 == char_type_node || type1 == unsigned_char_type_node)
+    return unsignedp ? unsigned_char_type_node : signed_char_type_node;
+  if (type1 == integer_type_node || type1 == unsigned_type_node)
+    return unsignedp ? unsigned_type_node : integer_type_node;
+  if (type1 == short_integer_type_node || type1 == short_unsigned_type_node)
+    return unsignedp ? short_unsigned_type_node : short_integer_type_node;
+  if (type1 == long_integer_type_node || type1 == long_unsigned_type_node)
+    return unsignedp ? long_unsigned_type_node : long_integer_type_node;
+  if (type1 == long_long_integer_type_node || type1 == long_long_unsigned_type_node)
+    return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
+  if (type1 == widest_integer_literal_type_node || type1 == widest_unsigned_literal_type_node)
+    return unsignedp ? widest_unsigned_literal_type_node : widest_integer_literal_type_node;
+#if HOST_BITS_PER_WIDE_INT >= 64
+  if (type1 == intTI_type_node || type1 == unsigned_intTI_type_node)
+    return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
+#endif
+  if (type1 == intDI_type_node || type1 == unsigned_intDI_type_node)
+    return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
+  if (type1 == intSI_type_node || type1 == unsigned_intSI_type_node)
+    return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
+  if (type1 == intHI_type_node || type1 == unsigned_intHI_type_node)
+    return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
+  if (type1 == intQI_type_node || type1 == unsigned_intQI_type_node)
+    return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
+
   /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
      the precision; they have precision set to match their range, but
      may use a wider mode to match an ABI.  If we change modes, we may