diff --git a/lld/COFF/Chunks.h b/lld/COFF/Chunks.h
index dc6de568c022..e5f5289ea984 100644
--- a/lld/COFF/Chunks.h
+++ b/lld/COFF/Chunks.h
@@ -183,6 +183,10 @@ public:
   // and this chunk is considrered as dead.
   SectionChunk *Ptr;
 
+  // The CRC of the contents as described in the COFF spec 4.5.5.
+  // Auxiliary Format 5: Section Definitions. Used for ICF.
+  uint32_t Checksum = 0;
+
 private:
   ArrayRef<uint8_t> getContents() const;
 
diff --git a/lld/COFF/ICF.cpp b/lld/COFF/ICF.cpp
index 4ec8f68fcf7a..1c23722d9bc7 100644
--- a/lld/COFF/ICF.cpp
+++ b/lld/COFF/ICF.cpp
@@ -44,7 +44,7 @@ uint64_t SectionChunk::getHash() const {
                       NumRelocs,
                       uint32_t(Header->SizeOfRawData),
                       std::distance(Relocs.end(), Relocs.begin()),
-                      hash_combine_range(A.data(), A.data() + A.size()));
+                      Checksum);
 }
 
 // Returns true if this and a given chunk are identical COMDAT sections.
@@ -58,6 +58,8 @@ bool SectionChunk::equals(const SectionChunk *X) const {
     return false;
   if (NumRelocs != X->NumRelocs)
     return false;
+  if (Checksum != X->Checksum)
+    return false;
 
   // Compare data
   if (getContents() != X->getContents())
diff --git a/lld/COFF/InputFiles.cpp b/lld/COFF/InputFiles.cpp
index a8a35a5cfde3..a8537ec39650 100644
--- a/lld/COFF/InputFiles.cpp
+++ b/lld/COFF/InputFiles.cpp
@@ -225,13 +225,14 @@ Defined *ObjectFile::createDefined(COFFSymbolRef Sym, const void *AuxP,
   if (!SC)
     return nullptr;
 
-  // Handle associative sections
+  // Handle section definitions
   if (IsFirst && AuxP) {
     auto *Aux = reinterpret_cast<const coff_aux_section_definition *>(AuxP);
     if (Aux->Selection == IMAGE_COMDAT_SELECT_ASSOCIATIVE)
       if (auto *ParentSC = cast_or_null<SectionChunk>(
               SparseChunks[Aux->getNumber(Sym.isBigObj())]))
         ParentSC->addAssociative(SC);
+    SC->Checksum = Aux->CheckSum;
   }
 
   auto *B = new (Alloc) DefinedRegular(this, Sym, SC);