Index: llvm/lib/Transforms/Scalar/SROA.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/SROA.cpp
+++ llvm/lib/Transforms/Scalar/SROA.cpp
@@ -2482,8 +2482,10 @@
     }
     V = convertValue(DL, IRB, V, NewAllocaTy);
     StoreInst *Store = IRB.CreateAlignedStore(V, &NewAI, NewAI.getAlignment());
+    auto LoopParMD =
+      makeArrayRef((unsigned)LLVMContext::MD_mem_parallel_loop_access);
+    Store->copyMetadata(SI, LoopParMD);
     Pass.DeadInsts.insert(&SI);
-    (void)Store;
     DEBUG(dbgs() << "          to: " << *Store << "\n");
     return true;
   }
@@ -2545,6 +2547,9 @@
       NewSI = IRB.CreateAlignedStore(V, NewPtr, getSliceAlign(V->getType()),
                                      SI.isVolatile());
     }
+    auto LoopParMD =
+      makeArrayRef((unsigned)LLVMContext::MD_mem_parallel_loop_access);
+    NewSI->copyMetadata(SI, LoopParMD);
     if (SI.isVolatile())
       NewSI->setAtomic(SI.getOrdering(), SI.getSynchScope());
     Pass.DeadInsts.insert(&SI);
@@ -3560,6 +3565,8 @@
 
     uint64_t PartOffset = 0, PartSize = Offsets.Splits.front();
     int Idx = 0, Size = Offsets.Splits.size();
+    auto LoopParMD =
+      makeArrayRef((unsigned)LLVMContext::MD_mem_parallel_loop_access);
     for (;;) {
       auto *PartTy = Type::getIntNTy(Ty->getContext(), PartSize * 8);
       auto *PartPtrTy = PartTy->getPointerTo(LI->getPointerAddressSpace());
@@ -3569,6 +3576,7 @@
                          PartPtrTy, BasePtr->getName() + "."),
           getAdjustedAlignment(LI, PartOffset, DL), /*IsVolatile*/ false,
           LI->getName());
+      PLoad->copyMetadata(*LI, LoopParMD); 
 
       // Append this load onto the list of split loads so we can find it later
       // to rewrite the stores.
@@ -3621,7 +3629,7 @@
                                   APInt(DL.getPointerSizeInBits(), PartOffset),
                                   PartPtrTy, StoreBasePtr->getName() + "."),
             getAdjustedAlignment(SI, PartOffset, DL), /*IsVolatile*/ false);
-        (void)PStore;
+        PStore->copyMetadata(*LI, LoopParMD);
         DEBUG(dbgs() << "      +" << PartOffset << ":" << *PStore << "\n");
       }
 
Index: llvm/test/Transforms/SROA/mem-par-metadata-sroa.ll
===================================================================
--- llvm/test/Transforms/SROA/mem-par-metadata-sroa.ll
+++ llvm/test/Transforms/SROA/mem-par-metadata-sroa.ll
@@ -0,0 +1,110 @@
+; RUN: opt < %s -sroa -S | FileCheck %s
+;
+; Make sure the llvm.mem.parallel_loop_access meta-data is preserved
+; when a load/store is replaced with another load/store by sroa
+;
+; class Complex {
+; private:
+;  float real_;
+;  float imaginary_;
+;
+; public:
+;   Complex() : real_(0), imaginary_(0) { }
+;   Complex(float real, float imaginary) : real_(real), imaginary_(imaginary) { }
+;   Complex(const Complex &rhs) : real_(rhs.real()), imaginary_(rhs.imaginary()) { }
+; 
+;   inline float real() const { return real_; }
+;   inline float imaginary() const { return imaginary_; }
+; 
+;   Complex operator+(const Complex& rhs) const
+;   {
+;     return Complex(real_ + rhs.real_, imaginary_ + rhs.imaginary_);
+;   }
+; };
+; 
+; void test(Complex *out, long size)
+; {
+;     #pragma clang loop vectorize(assume_safety)
+;     for (long offset = 0; offset < size; ++offset) {
+;       Complex t0 = out[offset];
+;       out[offset] = t0 + t0;
+;     }
+; }
+
+; CHECK: for.body:
+; CHECK-NOT:  store i32 %{{.*}}, i32* %{{.*}}, align 4
+; CHECK: store i32 %{{.*}}, i32* %{{.*}}, align 4, !llvm.mem.parallel_loop_access !1
+; CHECK-NOT:  store i32 %{{.*}}, i32* %{{.*}}, align 4
+; CHECK: store i32 %{{.*}}, i32* %{{.*}}, align 4, !llvm.mem.parallel_loop_access !1
+; CHECK-NOT:  store i32 %{{.*}}, i32* %{{.*}}, align 4
+; CHECK: br label
+
+; ModuleID = '<stdin>'
+source_filename = "mem-par-metadata-sroa1.cpp"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%class.Complex = type { float, float }
+
+; Function Attrs: norecurse nounwind uwtable
+define void @_Z4testP7Complexl(%class.Complex* nocapture %out, i64 %size) local_unnamed_addr #0 {
+entry:
+  %t0 = alloca %class.Complex, align 4
+  %ref.tmp = alloca i64, align 8
+  %tmpcast = bitcast i64* %ref.tmp to %class.Complex*
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.body, %entry
+  %offset.0 = phi i64 [ 0, %entry ], [ %inc, %for.body ]
+  %cmp = icmp slt i64 %offset.0, %size
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %arrayidx = getelementptr inbounds %class.Complex, %class.Complex* %out, i64 %offset.0
+  %real_.i = getelementptr inbounds %class.Complex, %class.Complex* %t0, i64 0, i32 0
+  %real_.i.i = getelementptr inbounds %class.Complex, %class.Complex* %arrayidx, i64 0, i32 0
+  %0 = load float, float* %real_.i.i, align 4, !llvm.mem.parallel_loop_access !1
+  store float %0, float* %real_.i, align 4, !llvm.mem.parallel_loop_access !1
+  %imaginary_.i = getelementptr inbounds %class.Complex, %class.Complex* %t0, i64 0, i32 1
+  %imaginary_.i.i = getelementptr inbounds %class.Complex, %class.Complex* %arrayidx, i64 0, i32 1
+  %1 = load float, float* %imaginary_.i.i, align 4, !llvm.mem.parallel_loop_access !1
+  store float %1, float* %imaginary_.i, align 4, !llvm.mem.parallel_loop_access !1
+  %arrayidx1 = getelementptr inbounds %class.Complex, %class.Complex* %out, i64 %offset.0
+  %real_.i1 = getelementptr inbounds %class.Complex, %class.Complex* %t0, i64 0, i32 0
+  %2 = load float, float* %real_.i1, align 4, !noalias !3, !llvm.mem.parallel_loop_access !1
+  %real_2.i = getelementptr inbounds %class.Complex, %class.Complex* %t0, i64 0, i32 0
+  %3 = load float, float* %real_2.i, align 4, !noalias !3, !llvm.mem.parallel_loop_access !1
+  %add.i = fadd float %2, %3
+  %imaginary_.i2 = getelementptr inbounds %class.Complex, %class.Complex* %t0, i64 0, i32 1
+  %4 = load float, float* %imaginary_.i2, align 4, !noalias !3, !llvm.mem.parallel_loop_access !1
+  %imaginary_3.i = getelementptr inbounds %class.Complex, %class.Complex* %t0, i64 0, i32 1
+  %5 = load float, float* %imaginary_3.i, align 4, !noalias !3, !llvm.mem.parallel_loop_access !1
+  %add4.i = fadd float %4, %5
+  %real_.i.i3 = getelementptr inbounds %class.Complex, %class.Complex* %tmpcast, i64 0, i32 0
+  store float %add.i, float* %real_.i.i3, align 4, !alias.scope !3, !llvm.mem.parallel_loop_access !1
+  %imaginary_.i.i4 = getelementptr inbounds %class.Complex, %class.Complex* %tmpcast, i64 0, i32 1
+  store float %add4.i, float* %imaginary_.i.i4, align 4, !alias.scope !3, !llvm.mem.parallel_loop_access !1
+  %6 = bitcast %class.Complex* %arrayidx1 to i64*
+  %7 = load i64, i64* %ref.tmp, align 8, !llvm.mem.parallel_loop_access !1
+  store i64 %7, i64* %6, align 4, !llvm.mem.parallel_loop_access !1
+  %inc = add nsw i64 %offset.0, 1
+  br label %for.cond, !llvm.loop !1
+
+for.end:                                          ; preds = %for.cond
+  ret void
+}
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1) #1
+
+attributes #0 = { norecurse nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 4.0.0 (cfe/trunk 277751)"}
+!1 = distinct !{!1, !2}
+!2 = !{!"llvm.loop.vectorize.enable", i1 true}
+!3 = !{!4}
+!4 = distinct !{!4, !5, !"_ZNK7ComplexplERKS_: %agg.result"}
+!5 = distinct !{!5, !"_ZNK7ComplexplERKS_"}