diff --git a/llvm/include/llvm/IR/Metadata.h b/llvm/include/llvm/IR/Metadata.h
--- a/llvm/include/llvm/IR/Metadata.h
+++ b/llvm/include/llvm/IR/Metadata.h
@@ -707,6 +707,10 @@
     Result.NoAlias = NoAlias;
     return Result;
   }
+
+  /// Create a new AAMDNode as the result after merging two pointers from two
+  /// mem ops into a single one.
+  AAMDNodes merge(const AAMDNodes &Other) const;
 };
 
 // Specialize DenseMapInfo for AAMDNodes.
@@ -1490,6 +1494,15 @@
 // Create wrappers for C Binding types (see CBindingWrapping.h).
 DEFINE_ISA_CONVERSION_FUNCTIONS(NamedMDNode, LLVMNamedMDNodeRef)
 
+inline AAMDNodes AAMDNodes::merge(const AAMDNodes &Other) const {
+  AAMDNodes Result;
+  Result.TBAA = MDNode::getMostGenericTBAA(TBAA, Other.TBAA);
+  Result.TBAAStruct = nullptr;
+  Result.Scope = MDNode::getMostGenericAliasScope(Scope, Other.Scope);
+  Result.NoAlias = MDNode::intersect(NoAlias, Other.NoAlias);
+  return Result;
+}
+
 } // end namespace llvm
 
 #endif // LLVM_IR_METADATA_H
diff --git a/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp b/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp
--- a/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp
@@ -522,20 +522,14 @@
 }
 
 void Instruction::getAAMetadata(AAMDNodes &N, bool Merge) const {
-  if (Merge) {
-    N.TBAA =
-        MDNode::getMostGenericTBAA(N.TBAA, getMetadata(LLVMContext::MD_tbaa));
-    N.TBAAStruct = nullptr;
-    N.Scope = MDNode::getMostGenericAliasScope(
-        N.Scope, getMetadata(LLVMContext::MD_alias_scope));
-    N.NoAlias =
-        MDNode::intersect(N.NoAlias, getMetadata(LLVMContext::MD_noalias));
-  } else {
-    N.TBAA = getMetadata(LLVMContext::MD_tbaa);
-    N.TBAAStruct = getMetadata(LLVMContext::MD_tbaa_struct);
-    N.Scope = getMetadata(LLVMContext::MD_alias_scope);
-    N.NoAlias = getMetadata(LLVMContext::MD_noalias);
-  }
+  AAMDNodes AAInfo;
+  AAInfo.TBAA = getMetadata(LLVMContext::MD_tbaa);
+  AAInfo.TBAAStruct = getMetadata(LLVMContext::MD_tbaa_struct);
+  AAInfo.Scope = getMetadata(LLVMContext::MD_alias_scope);
+  AAInfo.NoAlias = getMetadata(LLVMContext::MD_noalias);
+  if (Merge)
+    AAInfo = AAInfo.merge(N);
+  N = AAInfo;
 }
 
 static const MDNode *createAccessTag(const MDNode *AccessType) {
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -16876,6 +16876,22 @@
   unsigned SizeInBits = NumStores * ElementSizeBits;
   unsigned NumMemElts = MemVT.isVector() ? MemVT.getVectorNumElements() : 1;
 
+  Optional<MachineMemOperand::Flags> Flags;
+  AAMDNodes AAInfo;
+  for (unsigned I = 0; I != NumStores; ++I) {
+    StoreSDNode *St = cast<StoreSDNode>(StoreNodes[I].MemNode);
+    if (!Flags) {
+      Flags = St->getMemOperand()->getFlags();
+      AAInfo = St->getAAInfo();
+      continue;
+    }
+    // Skip merging if there's an inconsistent flag.
+    if (Flags != St->getMemOperand()->getFlags())
+      return false;
+    // Merge AA metadata.
+    AAInfo = AAInfo.merge(St->getAAInfo());
+  }
+
   EVT StoreTy;
   if (UseVector) {
     unsigned Elts = NumStores * NumMemElts;
@@ -16993,9 +17009,9 @@
   // make sure we use trunc store if it's necessary to be legal.
   SDValue NewStore;
   if (!UseTrunc) {
-    NewStore =
-        DAG.getStore(NewChain, DL, StoredVal, FirstInChain->getBasePtr(),
-                     FirstInChain->getPointerInfo(), FirstInChain->getAlign());
+    NewStore = DAG.getStore(NewChain, DL, StoredVal, FirstInChain->getBasePtr(),
+                            FirstInChain->getPointerInfo(),
+                            FirstInChain->getAlign(), Flags.getValue(), AAInfo);
   } else { // Must be realized as a trunc store
     EVT LegalizedStoredValTy =
         TLI.getTypeToTransformTo(*DAG.getContext(), StoredVal.getValueType());
@@ -17007,7 +17023,7 @@
     NewStore = DAG.getTruncStore(
         NewChain, DL, ExtendedStoreVal, FirstInChain->getBasePtr(),
         FirstInChain->getPointerInfo(), StoredVal.getValueType() /*TVT*/,
-        FirstInChain->getAlign(), FirstInChain->getMemOperand()->getFlags());
+        FirstInChain->getAlign(), Flags.getValue(), AAInfo);
   }
 
   // Replace all merged stores with the new store.
diff --git a/llvm/test/CodeGen/AArch64/merge-scoped-aa-store.ll b/llvm/test/CodeGen/AArch64/merge-scoped-aa-store.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/merge-scoped-aa-store.ll
@@ -0,0 +1,56 @@
+; RUN: llc %s -mtriple=aarch64-eabi -stop-after=finalize-isel -o - | FileCheck --check-prefix=MIR %s
+
+; Ensure the scoped AA metadata is still retained after store merging.
+
+; MIR-DAG: ![[DOMAIN:[0-9]+]] = distinct !{!{{[0-9]+}}, !"domain"}
+; MIR-DAG: ![[SCOPE0:[0-9]+]] = distinct !{!{{[0-9]+}}, ![[DOMAIN]], !"scope 0"}
+; MIR-DAG: ![[SCOPE1:[0-9]+]] = distinct !{!{{[0-9]+}}, ![[DOMAIN]], !"scope 1"}
+; MIR-DAG: ![[SCOPE2:[0-9]+]] = distinct !{!{{[0-9]+}}, ![[DOMAIN]], !"scope 2"}
+; MIR-DAG: ![[SCOPE3:[0-9]+]] = distinct !{!{{[0-9]+}}, ![[DOMAIN]], !"scope 3"}
+; MIR-DAG: ![[SET0:[0-9]+]] = !{![[SCOPE0]]}
+; MIR-DAG: ![[SET1:[0-9]+]] = !{![[SCOPE1]]}
+; MIR-DAG: ![[SET2:[0-9]+]] = !{![[SCOPE2]]}
+; MIR-DAG: ![[SET3:[0-9]+]] = !{![[SCOPE3]]}
+
+define void @blam(<3 x float>* %g0, <3 x float>* %g1) {
+; MIR-LABEL: name: blam
+; MIR: STRDui killed %5, %1, 0 :: (store (s64) into %ir.tmp41, align 4, !alias.scope ![[SET1]], !noalias ![[SET0]])
+  %tmp4 = getelementptr inbounds <3 x float>, <3 x float>* %g1, i64 0, i64 0
+  %tmp5 = load <3 x float>, <3 x float>* %g0, align 4, !alias.scope !0, !noalias !1
+  %tmp6 = extractelement <3 x float> %tmp5, i64 0
+  store float %tmp6, float* %tmp4, align 4, !alias.scope !1, !noalias !0
+  %tmp7 = getelementptr inbounds float, float* %tmp4, i64 1
+  %tmp8 = load <3 x float>, <3 x float>* %g0, align 4, !alias.scope !0, !noalias !1
+  %tmp9 = extractelement <3 x float> %tmp8, i64 1
+  store float %tmp9, float* %tmp7, align 4, !alias.scope !1, !noalias !0
+  ret void;
+}
+
+; Ensure new scoped AA metadata are calculated after merging stores.
+define void @blam1(<3 x float>* %g0, <3 x float>* %g1) {
+; MIR-LABEL: name: blam1
+; MIR: machineMetadataNodes:
+; MIR-DAG: ![[MMSET0:[0-9]+]] = !{![[SCOPE2]], ![[SCOPE1]]}
+; MIR-DAG: ![[MMSET1:[0-9]+]] = !{}
+; MIR: body:
+; MIR: STRDui killed %5, %1, 0 :: (store (s64) into %ir.tmp41, align 4, !alias.scope ![[MMSET0]], !noalias ![[MMSET1]])
+  %tmp4 = getelementptr inbounds <3 x float>, <3 x float>* %g1, i64 0, i64 0
+  %tmp5 = load <3 x float>, <3 x float>* %g0, align 4, !alias.scope !0, !noalias !1
+  %tmp6 = extractelement <3 x float> %tmp5, i64 0
+  store float %tmp6, float* %tmp4, align 4, !alias.scope !1, !noalias !0
+  %tmp7 = getelementptr inbounds float, float* %tmp4, i64 1
+  %tmp8 = load <3 x float>, <3 x float>* %g0, align 4, !alias.scope !0, !noalias !1
+  %tmp9 = extractelement <3 x float> %tmp8, i64 1
+  store float %tmp9, float* %tmp7, align 4, !alias.scope !5, !noalias !6
+  ret void;
+}
+
+!0 = !{!2}
+!1 = !{!3}
+!2 = !{!2, !4, !"scope 0"}
+!3 = !{!3, !4, !"scope 1"}
+!4 = !{!4, !"domain"}
+!5 = !{!7}
+!6 = !{!8}
+!7 = !{!7, !4, !"scope 2"}
+!8 = !{!8, !4, !"scope 3"}