diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -1019,12 +1019,10 @@
   case LibFunc_memset_pattern4:
   case LibFunc_memset_pattern8:
   case LibFunc_memset_pattern16:
-    Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setDoesNotCapture(F, 0);
-    Changed |= setOnlyWritesMemory(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    LLVM_FALLTHROUGH;
   case LibFunc_memset:
     Changed |= setWillReturn(F);
     LLVM_FALLTHROUGH;
diff --git a/llvm/test/Transforms/DeadStoreElimination/libcalls-darwin.ll b/llvm/test/Transforms/DeadStoreElimination/libcalls-darwin.ll
--- a/llvm/test/Transforms/DeadStoreElimination/libcalls-darwin.ll
+++ b/llvm/test/Transforms/DeadStoreElimination/libcalls-darwin.ll
@@ -10,9 +10,7 @@
 define void @test_memset_pattern4_const_size(i8* noalias %a, i8* noalias %pattern) {
 ; CHECK-LABEL: @test_memset_pattern4_const_size(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A_GEP_1:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 1
-; CHECK-NEXT:    store i8 0, i8* [[A_GEP_1]], align 1
-; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A]], i32 17
+; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 17
 ; CHECK-NEXT:    store i8 1, i8* [[A_GEP_17]], align 1
 ; CHECK-NEXT:    call void @memset_pattern4(i8* [[A]], i8* [[PATTERN:%.*]], i64 17)
 ; CHECK-NEXT:    ret void
@@ -48,9 +46,7 @@
 define void @test_memset_pattern8_const_size(i8* noalias %a, i8* noalias %pattern) {
 ; CHECK-LABEL: @test_memset_pattern8_const_size(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A_GEP_1:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 1
-; CHECK-NEXT:    store i8 0, i8* [[A_GEP_1]], align 1
-; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A]], i32 17
+; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 17
 ; CHECK-NEXT:    store i8 1, i8* [[A_GEP_17]], align 1
 ; CHECK-NEXT:    call void @memset_pattern8(i8* [[A]], i8* [[PATTERN:%.*]], i64 17)
 ; CHECK-NEXT:    ret void
@@ -86,9 +82,7 @@
 define void @test_memset_pattern16_const_size(i8* noalias %a, i8* noalias %pattern) {
 ; CHECK-LABEL: @test_memset_pattern16_const_size(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A_GEP_1:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 1
-; CHECK-NEXT:    store i8 0, i8* [[A_GEP_1]], align 1
-; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A]], i32 17
+; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 17
 ; CHECK-NEXT:    store i8 1, i8* [[A_GEP_17]], align 1
 ; CHECK-NEXT:    call void @memset_pattern16(i8* [[A]], i8* [[PATTERN:%.*]], i64 17)
 ; CHECK-NEXT:    ret void
diff --git a/llvm/test/Transforms/InferFunctionAttrs/annotate.ll b/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
--- a/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
+++ b/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
@@ -1055,11 +1055,11 @@
 
 
 ; memset_pattern{4,8,16} aren't available everywhere.
-; CHECK-DARWIN: declare void @memset_pattern4(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE:#[0-9]+]]
+; CHECK-DARWIN: declare void @memset_pattern4(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN]]
 declare void @memset_pattern4(i8*, i8*, i64)
-; CHECK-DARWIN: declare void @memset_pattern8(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE]]
+; CHECK-DARWIN: declare void @memset_pattern8(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN]]
 declare void @memset_pattern8(i8*, i8*, i64)
-; CHECK-DARWIN: declare void @memset_pattern16(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE]]
+; CHECK-DARWIN: declare void @memset_pattern16(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN]]
 declare void @memset_pattern16(i8*, i8*, i64)
 
 
@@ -1077,5 +1077,4 @@
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMORARGONLY_NOFREE_NOUNWIND_WILLRETURN]]  = { inaccessiblemem_or_argmemonly mustprogress nofree nounwind willreturn }
 ; CHECK-DAG: attributes [[ARGMEMONLY_NOFREE_NOUNWIND]] = { argmemonly nofree nounwind }
 
-; CHECK-DARWIN-DAG: attributes [[ARGMEMONLY_NOFREE]] = { argmemonly nofree }
 ; CHECK-NVPTX-DAG: attributes [[NOFREE_NOUNWIND_READNONE]] = { nofree nosync nounwind readnone }