diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 74cb5eb2b03a..0937241a0584 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-03-13  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR lto/84805
+	* ipa-devirt.c (odr_subtypes_equivalent_p): Do not get the ODR type of
+	incomplete types.
+
 2018-03-13  Martin Liska  <mliska@suse.cz>
 
 	PR ipa/84658.
diff --git a/gcc/ipa-devirt.c b/gcc/ipa-devirt.c
index fae82072a7e9..30d37574bbec 100644
--- a/gcc/ipa-devirt.c
+++ b/gcc/ipa-devirt.c
@@ -656,7 +656,7 @@ set_type_binfo (tree type, tree binfo)
       gcc_assert (!TYPE_BINFO (type));
 }
 
-/* Compare T2 and T2 based on name or structure.  */
+/* Compare T1 and T2 based on name or structure.  */
 
 static bool
 odr_subtypes_equivalent_p (tree t1, tree t2,
@@ -678,7 +678,7 @@ odr_subtypes_equivalent_p (tree t1, tree t2,
     return false;
 
   /* For ODR types be sure to compare their names.
-     To support -wno-odr-type-merging we allow one type to be non-ODR
+     To support -Wno-odr-type-merging we allow one type to be non-ODR
      and other ODR even though it is a violation.  */
   if (types_odr_comparable (t1, t2, true))
     {
@@ -690,6 +690,8 @@ odr_subtypes_equivalent_p (tree t1, tree t2,
 	 therefore which call will report the ODR violation, if any.  */
 	 if (!odr_type_p (t1)
 	     || !odr_type_p (t2)
+	     || !COMPLETE_TYPE_P (t1)
+	     || !COMPLETE_TYPE_P (t2)
 	     || (!get_odr_type (t1, true)->odr_violated
 		 && !get_odr_type (t2, true)->odr_violated))
         return true;