Index: lld/trunk/ELF/OutputSections.cpp
===================================================================
--- lld/trunk/ELF/OutputSections.cpp
+++ lld/trunk/ELF/OutputSections.cpp
@@ -345,6 +345,17 @@
 
 void OutputSectionFactory::addInputSec(InputSectionBase *IS,
                                        StringRef OutsecName) {
+  // Sections with the SHT_GROUP attribute reach here only when the - r option
+  // is given. Such sections define "section groups", and InputFiles.cpp has
+  // dedup'ed section groups by their signatures. For the -r, we want to pass
+  // through all SHT_GROUP sections without merging them because merging them
+  // creates broken section contents.
+  if (IS->Type == SHT_GROUP) {
+    OutputSection *Out = nullptr;
+    addInputSec(IS, OutsecName, Out);
+    return;
+  }
+
   SectionKey Key = createKey(IS, OutsecName);
   OutputSection *&Sec = Map[Key];
   return addInputSec(IS, OutsecName, Sec);
Index: lld/trunk/test/ELF/Inputs/relocatable-comdat-multiple.s
===================================================================
--- lld/trunk/test/ELF/Inputs/relocatable-comdat-multiple.s
+++ lld/trunk/test/ELF/Inputs/relocatable-comdat-multiple.s
@@ -0,0 +1,2 @@
+.section .text.c,"axG",@progbits,bbb,comdat
+.section .text.d,"axG",@progbits,bbb,comdat
Index: lld/trunk/test/ELF/relocatable-comdat-multiple.s
===================================================================
--- lld/trunk/test/ELF/relocatable-comdat-multiple.s
+++ lld/trunk/test/ELF/relocatable-comdat-multiple.s
@@ -0,0 +1,31 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %S/Inputs/relocatable-comdat-multiple.s -o %t2.o
+# RUN: ld.lld -r %t.o %t2.o -o %t
+# RUN: llvm-readobj -elf-section-groups %t | FileCheck %s
+
+# CHECK:      Groups {
+# CHECK-NEXT:   Group {
+# CHECK-NEXT:     Name: .group
+# CHECK-NEXT:     Index: 2
+# CHECK-NEXT:     Type: COMDAT
+# CHECK-NEXT:     Signature: aaa
+# CHECK-NEXT:     Section(s) in group [
+# CHECK-NEXT:       .text.a
+# CHECK-NEXT:       .text.b
+# CHECK-NEXT:     ]
+# CHECK-NEXT:   }
+# CHECK-NEXT:   Group {
+# CHECK-NEXT:     Name: .group
+# CHECK-NEXT:     Index: 5
+# CHECK-NEXT:     Type: COMDAT
+# CHECK-NEXT:     Signature: bbb
+# CHECK-NEXT:     Section(s) in group [
+# CHECK-NEXT:       .text.c
+# CHECK-NEXT:       .text.d
+# CHECK-NEXT:     ]
+# CHECK-NEXT:   }
+# CHECK-NEXT: }
+
+.section .text.a,"axG",@progbits,aaa,comdat
+.section .text.b,"axG",@progbits,aaa,comdat