Index: include/clang/Basic/TargetInfo.h
===================================================================
--- include/clang/Basic/TargetInfo.h
+++ include/clang/Basic/TargetInfo.h
@@ -1368,6 +1368,8 @@
 
   virtual void setAuxTarget(const TargetInfo *Aux) {}
 
+  virtual bool isPreserveDIAccessIndexNeeded() const { return false; }
+
 protected:
   /// Copy type and layout related info.
   void copyAuxTarget(const TargetInfo *Aux);
Index: lib/Basic/Targets/BPF.h
===================================================================
--- lib/Basic/Targets/BPF.h
+++ lib/Basic/Targets/BPF.h
@@ -22,9 +22,12 @@
 namespace targets {
 
 class LLVM_LIBRARY_VISIBILITY BPFTargetInfo : public TargetInfo {
+private:
+  const TargetOptions &TargetOpts;
+
 public:
-  BPFTargetInfo(const llvm::Triple &Triple, const TargetOptions &)
-      : TargetInfo(Triple) {
+  BPFTargetInfo(const llvm::Triple &Triple, const TargetOptions &Options)
+      : TargetInfo(Triple), TargetOpts(Options) {
     LongWidth = LongAlign = PointerWidth = PointerAlign = 64;
     SizeType = UnsignedLong;
     PtrDiffType = SignedLong;
@@ -46,7 +49,8 @@
                         MacroBuilder &Builder) const override;
 
   bool hasFeature(StringRef Feature) const override {
-    return Feature == "bpf" || Feature == "alu32" || Feature == "dwarfris";
+    return Feature == "bpf" || Feature == "alu32" || Feature == "dwarfris" ||
+           Feature == "offsetreloc";
   }
 
   void setFeatureEnabled(llvm::StringMap<bool> &Features, StringRef Name,
@@ -92,6 +96,16 @@
     StringRef CPUName(Name);
     return isValidCPUName(CPUName);
   }
+
+  bool isPreserveDIAccessIndexNeeded() const override {
+    const std::vector<std::string> &Features = TargetOpts.Features;
+    for (auto &Feature : Features) {
+      if (Feature == "+offsetreloc")
+        return true;
+    }
+
+    return false;
+  }
 };
 } // namespace targets
 } // namespace clang
Index: lib/CodeGen/CGBuilder.h
===================================================================
--- lib/CodeGen/CGBuilder.h
+++ lib/CodeGen/CGBuilder.h
@@ -298,6 +298,22 @@
     return CreateMemSet(Dest.getPointer(), Value, Size,
                         Dest.getAlignment().getQuantity(), IsVolatile);
   }
+
+  using CGBuilderBaseTy::CreatePreserveStructAccessIndex;
+  Address CreatePreserveStructAccessIndex(Address Addr,
+                                          llvm::StringRef StructName,
+                                          unsigned Index,
+                                          unsigned FieldIndex) {
+    llvm::StructType *ElTy = cast<llvm::StructType>(Addr.getElementType());
+    const llvm::DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
+    const llvm::StructLayout *Layout = DL.getStructLayout(ElTy);
+    auto Offset = CharUnits::fromQuantity(Layout->getElementOffset(Index));
+
+    return Address(CreatePreserveStructAccessIndex(Addr.getPointer(),
+                                                   StructName,
+                                                   Index, FieldIndex),
+                   Addr.getAlignment().alignmentAtOffset(Offset));
+  }
 };
 
 }  // end namespace CodeGen
Index: lib/CodeGen/CGExpr.cpp
===================================================================
--- lib/CodeGen/CGExpr.cpp
+++ lib/CodeGen/CGExpr.cpp
@@ -3350,8 +3350,19 @@
   CharUnits eltAlign =
     getArrayElementAlign(addr.getAlignment(), indices.back(), eltSize);
 
-  llvm::Value *eltPtr = emitArraySubscriptGEP(
-      CGF, addr.getPointer(), indices, inbounds, signedIndices, loc, name);
+  llvm::Value *eltPtr;
+  auto LastIndex = dyn_cast<llvm::ConstantInt>(indices.back());
+  if (!CGF.getTarget().isPreserveDIAccessIndexNeeded() || !LastIndex) {
+    eltPtr = emitArraySubscriptGEP(
+        CGF, addr.getPointer(), indices, inbounds, signedIndices, loc, name);
+  } else {
+    // Remember the original array subscript for bpf target
+    unsigned idx = LastIndex->getZExtValue();
+    eltPtr = CGF.Builder.CreatePreserveArrayAccessIndex(addr.getPointer(),
+                                                        indices.size() - 1,
+                                                        idx);
+  }
+
   return Address(eltPtr, eltAlign);
 }
 
@@ -3825,6 +3836,17 @@
   return CGF.Builder.CreateStructGEP(base, idx, field->getName());
 }
 
+static Address emitPreserveStructAccess(CodeGenFunction &CGF, Address base,
+                                        const FieldDecl *field) {
+  const RecordDecl *rec = field->getParent();
+
+  unsigned idx =
+      CGF.CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
+
+  return CGF.Builder.CreatePreserveStructAccessIndex(
+      base, rec->getName(), idx, field->getFieldIndex());
+}
+
 static bool hasAnyVptr(const QualType Type, const ASTContext &Context) {
   const auto *RD = Type.getTypePtr()->getAsCXXRecordDecl();
   if (!RD)
@@ -3932,9 +3954,21 @@
       // a barrier every time CXXRecord field with vptr is referenced.
       addr = Address(Builder.CreateLaunderInvariantGroup(addr.getPointer()),
                      addr.getAlignment());
+
+    if (getTarget().isPreserveDIAccessIndexNeeded())
+      // Remember the original union field index
+      addr = Address(
+          Builder.CreatePreserveUnionAccessIndex(
+              addr.getPointer(), rec->getName(), field->getFieldIndex()),
+          addr.getAlignment());
   } else {
-    // For structs, we GEP to the field that the record layout suggests.
-    addr = emitAddrOfFieldStorage(*this, addr, field);
+
+    if (!getTarget().isPreserveDIAccessIndexNeeded())
+      // For structs, we GEP to the field that the record layout suggests.
+      addr = emitAddrOfFieldStorage(*this, addr, field);
+    else
+      // Remember the original struct field index
+      addr = emitPreserveStructAccess(*this, addr, field);
 
     // If this is a reference field, load the reference right now.
     if (FieldType->isReferenceType()) {
Index: test/CodeGen/bpf-offsetreloc.c
===================================================================
--- /dev/null
+++ test/CodeGen/bpf-offsetreloc.c
@@ -0,0 +1,17 @@
+// RUN: %clang -target bpf -emit-llvm -S -Xclang -target-feature -Xclang +offsetreloc -o - %s > %t1
+// RUN: grep "llvm.preserve.struct.access.index" %t1
+// RUN: grep "llvm.preserve.array.access.index" %t1
+// RUN: grep "llvm.preserve.union.access.index" %t1
+
+struct t {
+  int i:1;
+  int j:2;
+  union {
+   int a;
+   int b;
+  } c[4];
+};
+
+void *test(struct t *arg) {
+  return &arg->c[3].b;
+}