diff --git a/lld/ELF/LTO.cpp b/lld/ELF/LTO.cpp
index f24327a139a2..228dc95d78fa 100644
--- a/lld/ELF/LTO.cpp
+++ b/lld/ELF/LTO.cpp
@@ -202,8 +202,6 @@ void BitcodeCompiler::add(BitcodeFile &F) {
       continue;
     }
     SymbolBody *B = S->body();
-    if (B->kind() != SymbolBody::DefinedRegularKind)
-      continue;
     if (B->File != &F)
       continue;
 
@@ -221,7 +219,12 @@ void BitcodeCompiler::add(BitcodeFile &F) {
     // needs to be able to replace the original definition without conflicting.
     // In the latter case, we need to allow the combined LTO object to provide a
     // definition with the same name, for example when doing parallel codegen.
-    undefine(S);
+    if (auto *C = dyn_cast<DefinedCommon>(B)) {
+      if (auto *GO = dyn_cast<GlobalObject>(GV))
+        GO->setAlignment(C->Alignment);
+    } else {
+      undefine(S);
+    }
 
     if (!GV)
       // Module asm symbol.
diff --git a/lld/ELF/SymbolTable.cpp b/lld/ELF/SymbolTable.cpp
index e99e5077d7ed..caae09787660 100644
--- a/lld/ELF/SymbolTable.cpp
+++ b/lld/ELF/SymbolTable.cpp
@@ -351,7 +351,7 @@ Symbol *SymbolTable<ELFT>::addCommon(StringRef N, uint64_t Size,
   bool WasInserted;
   std::tie(S, WasInserted) =
       insert(N, Type, StOther & 3, /*CanOmitFromDynSym*/ false, HasUnnamedAddr,
-             /*IsUsedInRegularObj*/ true, File);
+             !isa<BitcodeFile>(File), File);
   int Cmp = compareDefined(S, WasInserted, Binding);
   if (Cmp > 0) {
     S->Binding = Binding;
@@ -368,8 +368,9 @@ Symbol *SymbolTable<ELFT>::addCommon(StringRef N, uint64_t Size,
     if (Config->WarnCommon)
       warning("multiple common of " + S->body()->getName());
 
-    C->Size = std::max(C->Size, Size);
-    C->Alignment = std::max(C->Alignment, Alignment);
+    Alignment = C->Alignment = std::max(C->Alignment, Alignment);
+    if (Size > C->Size)
+      replaceBody<DefinedCommon>(S, N, Size, Alignment, StOther, Type, File);
   }
   return S;
 }
diff --git a/lld/test/ELF/lto/Inputs/common3.ll b/lld/test/ELF/lto/Inputs/common3.ll
new file mode 100644
index 000000000000..a4efc6591570
--- /dev/null
+++ b/lld/test/ELF/lto/Inputs/common3.ll
@@ -0,0 +1,3 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+@a = common hidden global i64 0, align 4
diff --git a/lld/test/ELF/lto/common2.ll b/lld/test/ELF/lto/common2.ll
index 59a2676e4fc9..6b740c4be701 100644
--- a/lld/test/ELF/lto/common2.ll
+++ b/lld/test/ELF/lto/common2.ll
@@ -7,15 +7,18 @@ target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 @a = common global i8 0, align 8
+; CHECK-DAG: @a = common global i8 0, align 8
 
-; Shared library case, we ensure that the bitcode generated file
-; has not the a symbol but is appears in the final shared library
-; produced.
-; CHECK-NOT: @a = common global i8 0, align 8
+@b = common hidden global i32 0, align 4
+define i32 @f() {
+  %t = load i32, i32* @b, align 4
+  ret i32 %t
+}
+; CHECK-DAG: @b = internal global i32 0, align 4
 
 ; SHARED: Symbol {
 ; SHARED:   Name: a
-; SHARED-NEXT:   Value: 0x2000
+; SHARED-NEXT:   Value:
 ; SHARED-NEXT:   Size: 1
 ; SHARED-NEXT:   Binding: Global
 ; SHARED-NEXT:   Type: Object
diff --git a/lld/test/ELF/lto/common3.ll b/lld/test/ELF/lto/common3.ll
new file mode 100644
index 000000000000..a6020ca8c927
--- /dev/null
+++ b/lld/test/ELF/lto/common3.ll
@@ -0,0 +1,14 @@
+; RUN: llvm-as %s -o %t1.o
+; RUN: llvm-as %S/Inputs/common3.ll -o %t2.o
+; RUN: ld.lld -m elf_x86_64 %t1.o %t2.o -o %t -shared -save-temps
+; RUN: llvm-dis < %t.lto.bc | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+@a = common hidden global i32 0, align 8
+define i32 @f() {
+  %t = load i32, i32* @a, align 4
+  ret i32 %t
+}
+
+; CHECK: @a = internal global i64 0, align 8