diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -952,6 +952,7 @@
     if (NewLinkage == GV.getLinkage())
       return;
     if (GlobalValue::isLocalLinkage(GV.getLinkage()) ||
+        GlobalValue::isLocalLinkage(NewLinkage) ||
         // In case it was dead and already converted to declaration.
         GV.isDeclaration())
       return;
diff --git a/llvm/test/ThinLTO/X86/not-internalized.ll b/llvm/test/ThinLTO/X86/not-internalized.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/not-internalized.ll
@@ -0,0 +1,34 @@
+; ModuleID = 'test.c'
+source_filename = "test.c"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; RUN: opt -module-summary %s -o %t.bc
+; RUN: llvm-lto2 run -save-temps %t.bc -o %t.out \
+; RUN:    -r=%t.bc,foo,plx \
+; RUN:    -r=%t.bc,bar,lx
+
+; Check that we don't internalize `bar` during promotion,
+; because foo and bar are members of the same comdat
+; RUN: llvm-dis %t.out.1.1.promote.bc -o - | FileCheck %s
+
+; Thin LTO internalization shouldn't internalize `bar` as well
+; RUN: llvm-dis %t.out.1.2.internalize.bc -o - | FileCheck %s
+
+; CHECK: define linkonce_odr dso_local i32 @bar() comdat($foo)
+
+$foo = comdat any
+
+; Function Attrs: noinline nounwind optnone uwtable
+define linkonce_odr dso_local i32 @bar() comdat($foo) {
+entry:
+  ret i32 33
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define linkonce_odr dso_local i32 @foo() comdat {
+entry:
+  %call = call i32 @bar()
+  %add = add nsw i32 42, %call
+  ret i32 %add
+}
diff --git a/llvm/test/ThinLTO/X86/weak_externals.ll b/llvm/test/ThinLTO/X86/weak_externals.ll
--- a/llvm/test/ThinLTO/X86/weak_externals.ll
+++ b/llvm/test/ThinLTO/X86/weak_externals.ll
@@ -7,10 +7,12 @@
 ; RUN:               -r=%t.bc,_ZZN9SingletonI1SE11getInstanceEvE8instance,lx \
 ; RUN:               -r=%t.bc,_ZZN9SingletonI1SE11getInstanceEvE13instance_weak,lx
 ; RUN: llvm-dis %t.out.1.1.promote.bc -o - | FileCheck %s
+; RUN: llvm-dis %t.out.1.2.internalize.bc -o - | FileCheck %s --check-prefix=INTERNALIZE
 
 ; CHECK: @_ZZN9SingletonI1SE11getInstanceEvE8instance = available_externally dso_local global %struct.S zeroinitializer
 ; CHECK: @_ZZN9SingletonI1SE11getInstanceEvE13instance_weak = available_externally dso_local global %struct.S* null, align 8
-; CHECK: define internal dereferenceable(16) %struct.S* @_ZN9SingletonI1SE11getInstanceEv() comdat
+; CHECK: define linkonce_odr dso_local dereferenceable(16) %struct.S* @_ZN9SingletonI1SE11getInstanceEv() comdat
+; INTERNALIZE: define internal dereferenceable(16) %struct.S* @_ZN9SingletonI1SE11getInstanceEv()
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"