diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 240859e9fed..25f8f5b6b7b 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,20 @@
+2020-03-17  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/94172
+	* c-tree.h (C_TYPE_INCOMPLETE_VARS): Define to TYPE_LANG_SLOT_1
+	instead of TYPE_VFIELD, and support it on {RECORD,UNION,ENUMERAL}_TYPE.
+	(TYPE_ACTUAL_ARG_TYPES): Check that it is only used on FUNCTION_TYPEs.
+	* c-decl.c (pushdecl): Push C_TYPE_INCOMPLETE_VARS also to
+	ENUMERAL_TYPEs.
+	(finish_incomplete_vars): New function, moved from finish_struct.  Use
+	relayout_decl instead of layout_decl.
+	(finish_struct): Remove obsolete comment about C_TYPE_INCOMPLETE_VARS
+	being TYPE_VFIELD.  Use finish_incomplete_vars.
+	(finish_enum): Clear C_TYPE_INCOMPLETE_VARS.  Call
+	finish_incomplete_vars.
+	* c-typeck.c (c_build_qualified_type): Clear C_TYPE_INCOMPLETE_VARS
+	also on ENUMERAL_TYPEs.
+
 2020-03-16  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/94179
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 87a0734b715..ed5163dd465 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -3312,7 +3312,8 @@ pushdecl (tree x)
 	element = TREE_TYPE (element);
       element = TYPE_MAIN_VARIANT (element);
 
-      if (RECORD_OR_UNION_TYPE_P (element)
+      if ((RECORD_OR_UNION_TYPE_P (element)
+	   || TREE_CODE (element) == ENUMERAL_TYPE)
 	  && (TREE_CODE (x) != TYPE_DECL
 	      || TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE)
 	  && !COMPLETE_TYPE_P (element))
@@ -8354,6 +8355,26 @@ field_decl_cmp (const void *x_p, const void *y_p)
   return 1;
 }
 
+/* If this structure or union completes the type of any previous
+   variable declaration, lay it out and output its rtl.  */
+static void
+finish_incomplete_vars (tree incomplete_vars, bool toplevel)
+{
+  for (tree x = incomplete_vars; x; x = TREE_CHAIN (x))
+    {
+      tree decl = TREE_VALUE (x);
+      if (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
+	layout_array_type (TREE_TYPE (decl));
+      if (TREE_CODE (decl) != TYPE_DECL)
+	{
+	  relayout_decl (decl);
+	  if (c_dialect_objc ())
+	    objc_check_decl (decl);
+	  rest_of_decl_compilation (decl, toplevel, 0);
+	}
+    }
+}
+
 /* Fill in the fields of a RECORD_TYPE or UNION_TYPE node, T.
    LOC is the location of the RECORD_TYPE or UNION_TYPE's definition.
    FIELDLIST is a chain of FIELD_DECL nodes for the fields.
@@ -8612,13 +8633,6 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes,
       warning_at (loc, 0, "union cannot be made transparent");
     }
 
-  /* Note: C_TYPE_INCOMPLETE_VARS overloads TYPE_VFIELD which is used
-     in dwarf2out via rest_of_decl_compilation below and means
-     something totally different.  Since we will be clearing
-     C_TYPE_INCOMPLETE_VARS shortly after we iterate through them,
-     clear it ahead of time and avoid problems in dwarf2out.  Ideally,
-     C_TYPE_INCOMPLETE_VARS should use some language specific
-     node.  */
   tree incomplete_vars = C_TYPE_INCOMPLETE_VARS (TYPE_MAIN_VARIANT (t));
   for (x = TYPE_MAIN_VARIANT (t); x; x = TYPE_NEXT_VARIANT (x))
     {
@@ -8639,21 +8653,7 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes,
   /* Finish debugging output for this type.  */
   rest_of_type_compilation (t, toplevel);
 
-  /* If this structure or union completes the type of any previous
-     variable declaration, lay it out and output its rtl.  */
-  for (x = incomplete_vars; x; x = TREE_CHAIN (x))
-    {
-      tree decl = TREE_VALUE (x);
-      if (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
-	layout_array_type (TREE_TYPE (decl));
-      if (TREE_CODE (decl) != TYPE_DECL)
-	{
-	  layout_decl (decl, 0);
-	  if (c_dialect_objc ())
-	    objc_check_decl (decl);
-	  rest_of_decl_compilation (decl, toplevel, 0);
-	}
-    }
+  finish_incomplete_vars (incomplete_vars, toplevel);
 
   /* If we're inside a function proper, i.e. not file-scope and not still
      parsing parameters, then arrange for the size of a variable sized type
@@ -8932,8 +8932,10 @@ finish_enum (tree enumtype, tree values, tree attributes)
   TYPE_LANG_SPECIFIC (enumtype) = lt;
 
   /* Fix up all variant types of this enum type.  */
+  tree incomplete_vars = C_TYPE_INCOMPLETE_VARS (TYPE_MAIN_VARIANT (enumtype));
   for (tem = TYPE_MAIN_VARIANT (enumtype); tem; tem = TYPE_NEXT_VARIANT (tem))
     {
+      C_TYPE_INCOMPLETE_VARS (tem) = NULL_TREE;
       if (tem == enumtype)
 	continue;
       TYPE_VALUES (tem) = TYPE_VALUES (enumtype);
@@ -8952,6 +8954,8 @@ finish_enum (tree enumtype, tree values, tree attributes)
   /* Finish debugging output for this type.  */
   rest_of_type_compilation (enumtype, toplevel);
 
+  finish_incomplete_vars (incomplete_vars, toplevel);
+
   /* If this enum is defined inside a struct, add it to
      struct_types.  */
   if (warn_cxx_compat
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index 71229927cb6..364d7e03398 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -38,9 +38,12 @@ along with GCC; see the file COPYING3.  If not see
    nonzero if the definition of the type has already started.  */
 #define C_TYPE_BEING_DEFINED(TYPE) TYPE_LANG_FLAG_0 (TYPE)
 
-/* In an incomplete RECORD_TYPE or UNION_TYPE, a list of variable
-   declarations whose type would be completed by completing that type.  */
-#define C_TYPE_INCOMPLETE_VARS(TYPE) TYPE_VFIELD (TYPE)
+/* In an incomplete RECORD_TYPE, UNION_TYPE or ENUMERAL_TYPE, a list of
+   variable declarations whose type would be completed by completing
+   that type.  */
+#define C_TYPE_INCOMPLETE_VARS(TYPE) \
+  TYPE_LANG_SLOT_1 (TREE_CHECK4 (TYPE, RECORD_TYPE, UNION_TYPE, \
+				 QUAL_UNION_TYPE, ENUMERAL_TYPE))
 
 /* In an IDENTIFIER_NODE, nonzero if this identifier is actually a
    keyword.  C_RID_CODE (node) is then the RID_* value of the keyword.  */
@@ -108,7 +111,8 @@ along with GCC; see the file COPYING3.  If not see
 /* For FUNCTION_TYPE, a hidden list of types of arguments.  The same as
    TYPE_ARG_TYPES for functions with prototypes, but created for functions
    without prototypes.  */
-#define TYPE_ACTUAL_ARG_TYPES(NODE) TYPE_LANG_SLOT_1 (NODE)
+#define TYPE_ACTUAL_ARG_TYPES(NODE) \
+  TYPE_LANG_SLOT_1 (FUNCTION_TYPE_CHECK (NODE))
 
 /* For a CONSTRUCTOR, whether some initializer contains a
    subexpression meaning it is not a constant expression.  */
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index 490d8fc5f4a..385bf3a1c7b 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -15207,7 +15207,8 @@ c_build_qualified_type (tree type, int type_quals, tree orig_qual_type,
 		   : build_qualified_type (type, type_quals));
   /* A variant type does not inherit the list of incomplete vars from the
      type main variant.  */
-  if (RECORD_OR_UNION_TYPE_P (var_type)
+  if ((RECORD_OR_UNION_TYPE_P (var_type)
+       || TREE_CODE (var_type) == ENUMERAL_TYPE)
       && TYPE_MAIN_VARIANT (var_type) != var_type)
     C_TYPE_INCOMPLETE_VARS (var_type) = 0;
   return var_type;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 45fb82941cc..dae22c27764 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,9 @@
 2020-03-17  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c/94172
+	* gcc.dg/pr94172-1.c: New test.
+	* gcc.dg/pr94172-2.c: New test.
+
 	PR c++/90995
 	* g++.dg/cpp0x/enum40.C: New test.
 
diff --git a/gcc/testsuite/gcc.dg/pr94172-1.c b/gcc/testsuite/gcc.dg/pr94172-1.c
new file mode 100644
index 00000000000..12f84af42dd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94172-1.c
@@ -0,0 +1,12 @@
+/* PR c/94172 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern enum E e;
+enum E { l = 0x100000000ULL };
+
+unsigned long long
+foo (void)
+{
+  return e;
+}
diff --git a/gcc/testsuite/gcc.dg/pr94172-2.c b/gcc/testsuite/gcc.dg/pr94172-2.c
new file mode 100644
index 00000000000..bb7b060d7b2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94172-2.c
@@ -0,0 +1,19 @@
+/* PR c/94172 */
+/* { dg-do compile } */
+/* { dg-options "-Os -g -fshort-enums" } */
+
+extern enum E e;
+extern void bar (int a);
+enum E { F };
+
+void
+foo (int a)
+{
+  int l = e;
+  if (a)
+    {
+      __asm volatile ("nop");
+      l = 0;
+    }
+  bar (l);
+}