diff --git a/llvm/lib/Linker/IRMover.cpp b/llvm/lib/Linker/IRMover.cpp
--- a/llvm/lib/Linker/IRMover.cpp
+++ b/llvm/lib/Linker/IRMover.cpp
@@ -1126,14 +1126,13 @@
     assert(CU && "Expected valid compile unit");
     // Enums, macros, and retained types don't need to be listed on the
     // imported DICompileUnit. This means they will only be imported
-    // if reached from the mapped IR. Do this by setting their value map
-    // entries to nullptr, which will automatically prevent their importing
-    // when reached from the DICompileUnit during metadata mapping.
-    ValueMap.MD()[CU->getRawEnumTypes()].reset(nullptr);
-    ValueMap.MD()[CU->getRawMacros()].reset(nullptr);
-    ValueMap.MD()[CU->getRawRetainedTypes()].reset(nullptr);
+    // if reached from the mapped IR.
+    CU->replaceEnumTypes(nullptr);
+    CU->replaceMacros(nullptr);
+    CU->replaceRetainedTypes(nullptr);
+
     // The original definition (or at least its debug info - if the variable is
-    // internalized an optimized away) will remain in the source module, so
+    // internalized and optimized away) will remain in the source module, so
     // there's no need to import them.
     // If LLVM ever does more advanced optimizations on global variables
     // (removing/localizing write operations, for instance) that can track
@@ -1141,7 +1140,7 @@
     // with care when it comes to debug info size. Emitting small CUs containing
     // only a few imported entities into every destination module may be very
     // size inefficient.
-    ValueMap.MD()[CU->getRawGlobalVariables()].reset(nullptr);
+    CU->replaceGlobalVariables(nullptr);
 
     // Imported entities only need to be mapped in if they have local
     // scope, as those might correspond to an imported entity inside a
@@ -1174,7 +1173,7 @@
       else
         // If there were no local scope imported entities, we can map
         // the whole list to nullptr.
-        ValueMap.MD()[CU->getRawImportedEntities()].reset(nullptr);
+        CU->replaceImportedEntities(nullptr);
     }
   }
 }
diff --git a/llvm/test/ThinLTO/X86/Inputs/import-metadata.ll b/llvm/test/ThinLTO/X86/Inputs/import-metadata.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/Inputs/import-metadata.ll
@@ -0,0 +1,23 @@
+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-scei-ps4"
+
+define i32 @foo(i32 %goo) {
+entry:
+  %goo.addr = alloca i32, align 4
+  store i32 %goo, i32* %goo.addr, align 4
+  %0 = load i32, i32* %goo.addr, align 4
+  %1 = load i32, i32* %goo.addr, align 4
+  %mul = mul nsw i32 %0, %1
+  ret i32 %mul
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2, !3}
+!llvm.md = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, enums: !4)
+!1 = !DIFile(filename: "foo.cpp", directory: "tmp")
+!2 = !{i32 2, !"Dwarf Version", i32 4}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{}
+!5 = !{!4}
diff --git a/llvm/test/ThinLTO/X86/import-metadata.ll b/llvm/test/ThinLTO/X86/import-metadata.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/import-metadata.ll
@@ -0,0 +1,40 @@
+; RUN: opt -thinlto-bc %s -o %t1.bc
+; RUN: opt -thinlto-bc %p/Inputs/import-metadata.ll -o %t2.bc
+; RUN: llvm-lto2 run -save-temps %t1.bc %t2.bc -o %t-out \
+; RUN:    -r=%t1.bc,main,plx \
+; RUN:    -r=%t1.bc,foo,l \
+; RUN:    -r=%t2.bc,foo,pl
+; RUN: llvm-dis %t-out.1.3.import.bc -o - | FileCheck %s
+
+;; Check the imported DICompileUnit doesn't have the enums operand.
+;; Also check the imported md metadata that shares a node with the 
+;; enums operand originally is not null.
+
+; CHECK: !llvm.dbg.cu = !{![[#CU1:]], ![[#CU2:]]}
+;; Note that MD1 comes from the current module. MD2 is from the imported module. 
+;; We are checking if the imported MD2 doesn't end up having a null operand.
+; CHECK: !llvm.md = !{![[#MD1:]], ![[#MD2:]]}
+; CHECK: ![[#MD3:]] = !{}
+; CHECK: ![[#CU2]] = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: ![[#FILE2:]], isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug)
+; CHECK: ![[#MD2]] = !{![[#MD3]]}
+
+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-scei-ps4"
+
+declare i32 @foo(i32 %goo)
+
+define i32 @main() {
+  call i32 @foo(i32 0)
+  ret i32 0
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2, !3}
+!llvm.md = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, enums: !4)
+!1 = !DIFile(filename: "main.cpp", directory: "tmp")
+!2 = !{i32 2, !"Dwarf Version", i32 4}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{}
+!5 = !{!4}