Index: lib/Transforms/IPO/Internalize.cpp
===================================================================
--- lib/Transforms/IPO/Internalize.cpp
+++ lib/Transforms/IPO/Internalize.cpp
@@ -119,10 +119,6 @@
     if (ExternalComdats.count(C))
       return false;
 
-    // If a comdat is not externally visible we can drop it.
-    if (auto GO = dyn_cast<GlobalObject>(&GV))
-      GO->setComdat(nullptr);
-
     if (GV.hasLocalLinkage())
       return false;
   } else {
Index: test/Transforms/Internalize/comdat.ll
===================================================================
--- test/Transforms/Internalize/comdat.ll
+++ test/Transforms/Internalize/comdat.ll
@@ -8,7 +8,7 @@
 ; CHECK: @c1_c = global i32 0, comdat($c1)
 @c1_c = global i32 0, comdat($c1)
 
-; CHECK: @c2_b = internal global i32 0{{$}}
+; CHECK: @c2_b = internal global i32 0, comdat($c2)
 @c2_b = global i32 0, comdat($c2)
 
 ; CHECK: @c3 = global i32 0, comdat{{$}}
@@ -36,12 +36,12 @@
   ret void
 }
 
-; CHECK: define internal void @c2() {
+; CHECK: define internal void @c2() comdat {
 define internal void @c2() comdat {
   ret void
 }
 
-; CHECK: define internal void @c2_a() {
+; CHECK: define internal void @c2_a() comdat($c2) {
 define void @c2_a() comdat($c2) {
   ret void
 }
Index: test/Transforms/Internalize/preserve-comdat-members.ll
===================================================================
--- /dev/null
+++ test/Transforms/Internalize/preserve-comdat-members.ll
@@ -0,0 +1,19 @@
+; Running internalize followed by globaldce should preserve unused globals that share a COMDAT with used globals
+; RUN: opt < %s -internalize -internalize-public-api-list c1 -globaldce  -S | FileCheck %s
+
+$c1 = comdat any
+
+; Since both used_global and and unused_fn share a COMDAT, they should both be kept,
+; keeping the !associated metadata pointing at unused_fn
+; CHECK: @used_global = internal global i32 0, comdat($c1), !associated !0
+@used_global = global i32 0, comdat($c1), !associated !0
+
+@llvm.used = appending global [1 x i32*] [i32* @used_global], section "llvm.metadata"
+
+; CHECK: define internal void @unused_fn() comdat($c1) {
+define void @unused_fn() comdat($c1) {
+  ret void
+}
+
+; CHECK: !0 = !{void ()* @unused_fn}
+!0 = !{void ()* @unused_fn}
\ No newline at end of file