diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -1680,7 +1680,7 @@
 
   for (InputFile *file : lto->compile()) {
     auto *obj = cast<ObjFile<ELFT>>(file);
-    obj->parse(/*ignoreComdats=*/true);
+    obj->parse(/*isBitcodeFile=*/true);
     for (Symbol *sym : obj->getGlobalSymbols())
       sym->parseSymbolVersion();
     objectFiles.push_back(file);
diff --git a/lld/ELF/InputFiles.h b/lld/ELF/InputFiles.h
--- a/lld/ELF/InputFiles.h
+++ b/lld/ELF/InputFiles.h
@@ -201,7 +201,7 @@
     this->archiveName = std::string(archiveName);
   }
 
-  void parse(bool ignoreComdats = false);
+  void parse(bool isBitcodeFile = false);
 
   StringRef getShtGroupSignature(ArrayRef<Elf_Shdr> sections,
                                  const Elf_Shdr &sec);
@@ -252,7 +252,7 @@
   DWARFCache *getDwarf();
 
 private:
-  void initializeSections(bool ignoreComdats);
+  void initializeSections(bool isBitcodeFile);
   void initializeSymbols();
   void initializeJustSymbols();
 
diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -390,12 +390,12 @@
   return makeArrayRef(this->symbols).slice(this->firstGlobal);
 }
 
-template <class ELFT> void ObjFile<ELFT>::parse(bool ignoreComdats) {
+template <class ELFT> void ObjFile<ELFT>::parse(bool isBitcodeFile) {
   // Read a section table. justSymbols is usually false.
   if (this->justSymbols)
     initializeJustSymbols();
   else
-    initializeSections(ignoreComdats);
+    initializeSections(isBitcodeFile);
 
   // Read a symbol table.
   initializeSymbols();
@@ -546,7 +546,7 @@
 }
 
 template <class ELFT>
-void ObjFile<ELFT>::initializeSections(bool ignoreComdats) {
+void ObjFile<ELFT>::initializeSections(bool isBitcodeFile) {
   const ELFFile<ELFT> &obj = this->getObj();
 
   ArrayRef<Elf_Shdr> objSections = CHECK(obj.sections(), this);
@@ -607,10 +607,15 @@
       if (entries[0] != GRP_COMDAT)
         fatal(toString(this) + ": unsupported SHT_GROUP format");
 
-      bool isNew =
-          ignoreComdats ||
-          symtab->comdatGroups.try_emplace(CachedHashStringRef(signature), this)
-              .second;
+      // If this is a bitcode file, ignore already proceed comdat groups.
+      // Else, check all comdat groups.
+      bool isNew = isBitcodeFile
+                       ? symtab->bitcodeComdatGroups
+                             .try_emplace(CachedHashStringRef(signature), this)
+                             .second
+                       : symtab->comdatGroups
+                             .try_emplace(CachedHashStringRef(signature), this)
+                             .second;
       if (isNew) {
         if (config->relocatable)
           this->sections[i] = createInputSection(sec);
@@ -1561,9 +1566,10 @@
 
 template <class ELFT> void BitcodeFile::parse() {
   std::vector<bool> keptComdats;
-  for (StringRef s : obj->getComdatTable())
+  for (StringRef s : obj->getComdatTable()) {
     keptComdats.push_back(
         symtab->comdatGroups.try_emplace(CachedHashStringRef(s), this).second);
+  }
 
   for (const lto::InputFile::Symbol &objSym : obj->symbols())
     symbols.push_back(createBitcodeSymbol<ELFT>(keptComdats, objSym, *this));
diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
--- a/lld/ELF/Relocations.cpp
+++ b/lld/ELF/Relocations.cpp
@@ -694,8 +694,12 @@
 
   // If the discarded section is a COMDAT.
   StringRef signature = file->getShtGroupSignature(objSections, elfSec);
-  if (const InputFile *prevailing =
-          symtab->comdatGroups.lookup(CachedHashStringRef(signature)))
+  const InputFile *prevailing =
+      symtab->comdatGroups.lookup(CachedHashStringRef(signature));
+  if (!prevailing)
+    prevailing =
+        symtab->bitcodeComdatGroups.lookup(CachedHashStringRef(signature));
+  if (prevailing)
     msg += "\n>>> section group signature: " + signature.str() +
            "\n>>> prevailing definition is in " + toString(prevailing);
   return msg;
diff --git a/lld/ELF/SymbolTable.h b/lld/ELF/SymbolTable.h
--- a/lld/ELF/SymbolTable.h
+++ b/lld/ELF/SymbolTable.h
@@ -63,6 +63,12 @@
   // is used to uniquify them.
   llvm::DenseMap<llvm::CachedHashStringRef, const InputFile *> comdatGroups;
 
+  // We link twice in thinlto.  Define a separate map of comdat groups for
+  // bitcode files to make sure the symbols are distinct fromt the ones found
+  // in object files
+  llvm::DenseMap<llvm::CachedHashStringRef, const InputFile *>
+      bitcodeComdatGroups;
+
 private:
   std::vector<Symbol *> findByVersion(SymbolVersion ver);
   std::vector<Symbol *> findAllByVersion(SymbolVersion ver);