Index: ELF/SyntheticSections.h
===================================================================
--- ELF/SyntheticSections.h
+++ ELF/SyntheticSections.h
@@ -684,6 +684,7 @@
 class MergeSyntheticSection : public SyntheticSection {
 public:
   void addSection(MergeInputSection *MS);
+  void writeTo(uint8_t *Buf) override;
 
 protected:
   MergeSyntheticSection(StringRef Name, uint32_t Type, uint64_t Flags,
@@ -699,7 +700,6 @@
                    uint32_t Alignment);
 
   size_t getSize() const override;
-  void writeTo(uint8_t *Buf) override;
   void finalizeContents() override;
 
 private:
@@ -713,7 +713,6 @@
       : MergeSyntheticSection(Name, Type, Flags, Alignment) {}
 
   size_t getSize() const override { return Size; }
-  void writeTo(uint8_t *Buf) override;
   void finalizeContents() override;
 
 private:
Index: ELF/SyntheticSections.cpp
===================================================================
--- ELF/SyntheticSections.cpp
+++ ELF/SyntheticSections.cpp
@@ -2407,6 +2407,10 @@
   Sections.push_back(MS);
 }
 
+void MergeSyntheticSection::writeTo(uint8_t *Buf) {
+  memcpy(Buf, Data.data(), Data.size());
+}
+
 MergeTailSection::MergeTailSection(StringRef Name, uint32_t Type,
                                    uint64_t Flags, uint32_t Alignment)
     : MergeSyntheticSection(Name, Type, Flags, Alignment),
@@ -2414,8 +2418,6 @@
 
 size_t MergeTailSection::getSize() const { return Builder.getSize(); }
 
-void MergeTailSection::writeTo(uint8_t *Buf) { Builder.write(Buf); }
-
 void MergeTailSection::finalizeContents() {
   // Add all string pieces to the string table builder to create section
   // contents.
@@ -2434,11 +2436,13 @@
     for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
       if (Sec->Pieces[I].Live)
         Sec->Pieces[I].OutputOff = Builder.getOffset(Sec->getData(I));
-}
 
-void MergeNoTailSection::writeTo(uint8_t *Buf) {
-  for (size_t I = 0; I < NumShards; ++I)
-    Shards[I].write(Buf + ShardOffsets[I]);
+  // Populate data.
+  size_t Size = Builder.getSize();
+  uint8_t *Buf = new (BAlloc) uint8_t[Size];
+  Data = ArrayRef<uint8_t>(Buf, Size);
+  memset(Buf, 0, Size);
+  Builder.write(Buf);
 }
 
 // This function is very hot (i.e. it can take several seconds to finish)
@@ -2491,6 +2495,13 @@
         Sec->Pieces[I].OutputOff +=
             ShardOffsets[getShardId(Sec->Pieces[I].Hash)];
   });
+
+  // Populate data.
+  uint8_t *Buf = new (BAlloc) uint8_t[Size];
+  Data = ArrayRef<uint8_t>(Buf, Size);
+  memset(Buf, 0, Size);
+  for (size_t I = 0; I < NumShards; ++I)
+    Shards[I].write(Buf + ShardOffsets[I]);
 }
 
 static MergeSyntheticSection *createMergeSynthetic(StringRef Name,
Index: test/ELF/icf-not-equal-merged-sections.s
===================================================================
--- /dev/null
+++ test/ELF/icf-not-equal-merged-sections.s
@@ -0,0 +1,36 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
+# RUN: ld.lld %t.o -o %t --icf=all --ignore-data-address-equality --print-icf-sections | FileCheck -allow-empty %s
+# RUN: llvm-readobj -s -section-data %t | FileCheck --check-prefix=NODEDUP %s
+
+# CHECK-NOT: selected section <internal>:(.rodata)
+
+# NODEDUP:      Name: .rodata
+# NODEDUP-NEXT: Type: SHT_PROGBITS
+# NODEDUP-NEXT: Flags [
+# NODEDUP-NEXT:   SHF_ALLOC
+# NODEDUP-NEXT:   SHF_MERGE
+# NODEDUP-NEXT: ]
+# NODEDUP-NEXT: Address:
+# NODEDUP-NEXT: Offset:
+# NODEDUP-NEXT: Size: 16
+# NODEDUP-NEXT: Link:
+# NODEDUP-NEXT: Info:
+# NODEDUP-NEXT: AddressAlignment: 8
+# NODEDUP-NEXT: EntrySize: 0
+# NODEDUP-NEXT: SectionData (
+# NODEDUP-NEXT:   0000: 77665544 33221100 67452301 10325476
+# NODEDUP-NEXT: )
+
+.section .rodata.cst4,"aM",@progbits,4
+rodata4:
+  .long 0x00112233
+  .long 0x44556677
+  .long 0x00112233
+  .long 0x44556677
+
+.section .rodata.cst8,"aM",@progbits,8
+rodata8:
+  .long 0x01234567
+  .long 0x76543210