diff --git a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
--- a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
+++ b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
@@ -831,8 +831,14 @@
     Builder.Insert(GEP);
     StoreInst *NSI = Builder.CreateStore(NewElement, GEP);
     NSI->copyMetadata(*SI);
-    if (SI->getAlign() < NSI->getAlign())
-      NSI->setAlignment(SI->getAlign());
+    Align NewAlignment(1);
+    if (auto *C = dyn_cast<ConstantInt>(Idx)) {
+      NewAlignment = std::max(SI->getAlign(), Load->getAlign());
+      NewAlignment = commonAlignment(
+          NewAlignment,
+          C->getZExtValue() * DL.getTypeStoreSize(NewElement->getType()));
+    }
+    NSI->setAlignment(NewAlignment);
     replaceValue(I, *NSI);
     // Need erasing the store manually.
     I.eraseFromParent();
diff --git a/llvm/test/Transforms/VectorCombine/load-insert-store.ll b/llvm/test/Transforms/VectorCombine/load-insert-store.ll
--- a/llvm/test/Transforms/VectorCombine/load-insert-store.ll
+++ b/llvm/test/Transforms/VectorCombine/load-insert-store.ll
@@ -20,7 +20,7 @@
 ; CHECK-LABEL: @insert_store_i16_align1(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr inbounds <8 x i16>, <8 x i16>* [[Q:%.*]], i32 0, i32 3
-; CHECK-NEXT:    store i16 [[S:%.*]], i16* [[TMP0]], align 1
+; CHECK-NEXT:    store i16 [[S:%.*]], i16* [[TMP0]], align 2
 ; CHECK-NEXT:    ret void
 ;
 entry: