diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -288,7 +288,8 @@
 }
 
 static Value* mergeAttributesAndFlags(CallInst *NewCI, const CallInst &Old) {
-  NewCI->setAttributes(Old.getAttributes());
+  NewCI->setAttributes(AttributeList::get(
+      NewCI->getContext(), {NewCI->getAttributes(), Old.getAttributes()}));
   NewCI->removeRetAttrs(AttributeFuncs::typeIncompatible(NewCI->getType()));
   return copyFlags(Old, NewCI);
 }
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/memset_chk-simplify-nobuiltin.ll b/llvm/test/Transforms/CodeGenPrepare/X86/memset_chk-simplify-nobuiltin.ll
--- a/llvm/test/Transforms/CodeGenPrepare/X86/memset_chk-simplify-nobuiltin.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/memset_chk-simplify-nobuiltin.ll
@@ -11,7 +11,7 @@
 
 define void @test_nobuiltin(i8* %dst, i64 %len) {
 ; CHECK-LABEL: @test_nobuiltin(
-; CHECK-NEXT:    call void @llvm.memset.p0i8.i64(i8* [[DST:%.*]], i8 0, i64 [[LEN:%.*]], i1 false) #1
+; CHECK-NEXT:    call void @llvm.memset.p0i8.i64(i8* align 1 [[DST:%.*]], i8 0, i64 [[LEN:%.*]], i1 false)
 ; CHECK-NEXT:    ret void
 ;
   call i8* @__memset_chk(i8* %dst, i32 0, i64 %len, i64 -1) nobuiltin