Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -1303,9 +1303,10 @@
 
   // Do size optimizations: garbage collection, merging of SHF_MERGE sections
   // and identical code folding.
+  decompressSections();
+  splitSections();
   markLive<ELFT>();
   demoteSymbols<ELFT>();
-  decompressSections();
   mergeSections();
   if (Config->ICF)
     doIcf<ELFT>();
Index: ELF/InputSection.h
===================================================================
--- ELF/InputSection.h
+++ ELF/InputSection.h
@@ -224,10 +224,7 @@
   void splitIntoPieces();
 
   // Mark the piece at a given offset live. Used by GC.
-  void markLiveAt(uint64_t Offset) {
-    if (this->Flags & llvm::ELF::SHF_ALLOC)
-      LiveOffsets.insert(Offset);
-  }
+  void markLiveAt(uint64_t Offset);
 
   // Translate an offset in the input section to an offset in the parent
   // MergeSyntheticSection.
@@ -259,8 +256,6 @@
 private:
   void splitStrings(ArrayRef<uint8_t> A, size_t Size);
   void splitNonStrings(ArrayRef<uint8_t> A, size_t Size);
-
-  llvm::DenseSet<uint32_t> LiveOffsets;
 };
 
 struct EhSectionPiece {
Index: ELF/InputSection.cpp
===================================================================
--- ELF/InputSection.cpp
+++ ELF/InputSection.cpp
@@ -909,6 +909,10 @@
     : InputSectionBase(nullptr, Flags, Type, Entsize, /*Link*/ 0, /*Info*/ 0,
                        /*Alignment*/ Entsize, Data, Name, SectionBase::Merge) {}
 
+void MergeInputSection::markLiveAt(uint64_t Offset) {
+  getSectionPiece(Offset)->Live = true;
+}
+
 // This function is called after we obtain a complete list of input sections
 // that need to be linked. This is responsible to split section contents
 // into small chunks for further processing.
@@ -926,10 +930,6 @@
   OffsetMap.reserve(Pieces.size());
   for (size_t I = 0, E = Pieces.size(); I != E; ++I)
     OffsetMap[Pieces[I].InputOff] = I;
-
-  if (Config->GcSections && (Flags & SHF_ALLOC))
-    for (uint32_t Off : LiveOffsets)
-      getSectionPiece(Off)->Live = true;
 }
 
 template <class It, class T, class Compare>
Index: ELF/SyntheticSections.h
===================================================================
--- ELF/SyntheticSections.h
+++ ELF/SyntheticSections.h
@@ -834,6 +834,7 @@
 InputSection *createInterpSection();
 MergeInputSection *createCommentSection();
 void decompressSections();
+void splitSections();
 void mergeSections();
 
 Defined *addSyntheticLocal(StringRef Name, uint8_t Type, uint64_t Value,
Index: ELF/SyntheticSections.cpp
===================================================================
--- ELF/SyntheticSections.cpp
+++ ELF/SyntheticSections.cpp
@@ -2536,9 +2536,16 @@
 
 // Debug sections may be compressed by zlib. Decompress if exists.
 void elf::decompressSections() {
+  parallelForEach(InputSections,
+                  [](InputSectionBase *Sec) { Sec->maybeDecompress(); });
+}
+
+void elf::splitSections() {
+  // splitIntoPieces needs to be called on each MergeInputSection
+  // before calling finalizeContents().
   parallelForEach(InputSections, [](InputSectionBase *Sec) {
-    if (Sec->Live)
-      Sec->maybeDecompress();
+    if (auto *S = dyn_cast<MergeInputSection>(Sec))
+      S->splitIntoPieces();
   });
 }
 
@@ -2550,13 +2557,6 @@
 // that it replaces. It then finalizes each synthetic section in order
 // to compute an output offset for each piece of each input section.
 void elf::mergeSections() {
-  // splitIntoPieces needs to be called on each MergeInputSection
-  // before calling finalizeContents(). Do that first.
-  parallelForEach(InputSections, [](InputSectionBase *Sec) {
-    if (auto *S = dyn_cast<MergeInputSection>(Sec))
-      S->splitIntoPieces();
-  });
-
   std::vector<MergeSyntheticSection *> MergeSections;
   for (InputSectionBase *&S : InputSections) {
     MergeInputSection *MS = dyn_cast<MergeInputSection>(S);