diff --git a/llvm/include/llvm-c/lto.h b/llvm/include/llvm-c/lto.h
index 1db077822ae2..9f37dd71e31c 100644
--- a/llvm/include/llvm-c/lto.h
+++ b/llvm/include/llvm-c/lto.h
@@ -62,7 +62,8 @@ typedef enum {
     LTO_SYMBOL_SCOPE_HIDDEN                = 0x00001000,
     LTO_SYMBOL_SCOPE_PROTECTED             = 0x00002000,
     LTO_SYMBOL_SCOPE_DEFAULT               = 0x00001800,
-    LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN = 0x00002800
+    LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN = 0x00002800,
+    LTO_SYMBOL_COMDAT                      = 0x00004000
 } lto_symbol_attributes;
 
 /**
diff --git a/llvm/lib/LTO/LTOModule.cpp b/llvm/lib/LTO/LTOModule.cpp
index 5cdbca66a80e..0794d3c9ea4a 100644
--- a/llvm/lib/LTO/LTOModule.cpp
+++ b/llvm/lib/LTO/LTOModule.cpp
@@ -468,6 +468,9 @@ void LTOModule::addDefinedSymbol(const char *Name, const GlobalValue *def,
   else
     attr |= LTO_SYMBOL_SCOPE_DEFAULT;
 
+  if (def->hasComdat())
+    attr |= LTO_SYMBOL_COMDAT;
+
   auto Iter = _defines.insert(Name).first;
 
   // fill information structure