diff --git a/clang/test/AST/HLSL/ArrayOutArgExpr.hlsl b/clang/test/AST/HLSL/ArrayOutArgExpr.hlsl
new file mode 100644
index 00000000000000..10825bf0f93bc7
--- /dev/null
+++ b/clang/test/AST/HLSL/ArrayOutArgExpr.hlsl
@@ -0,0 +1,63 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-library -x hlsl -ast-dump %s | FileCheck %s
+
+// CHECK-LABEL: increment
+void increment(inout int Arr[2]) {
+  for (int I = 0; I < 2; I++)
+    Arr[0] += 2;
+}
+
+// CHECK-LABEL: call
+// CHECK: CallExpr 0x{{.*}} {{.*}} 'void'
+// CHECK: ImplicitCastExpr 0x{{.*}} {{.*}} 'void (*)(inout int[2])' <FunctionToPointerDecay>
+// CHECK: DeclRefExpr 0x{{.*}} {{.*}} 'void (inout int[2])' lvalue Function 0x{{.*}} 'increment' 'void (inout int[2])'
+// CHECK: HLSLOutArgExpr 0x{{.*}} {{.*}} 'int[2]' lvalue inout
+// CHECK: OpaqueValueExpr [[A:0x.*]] {{.*}} 'int[2]' lvalue
+// CHECK: DeclRefExpr [[B:0x.*]] {{.*}} 'int[2]' lvalue Var [[E:0x.*]] 'A' 'int[2]'
+// CHECK: OpaqueValueExpr [[C:0x.*]] {{.*}} 'int[2]' lvalue
+// CHECK: ImplicitCastExpr [[D:0x.*]] {{.*}} 'int[2]' <HLSLArrayRValue>
+// CHECK: OpaqueValueExpr [[A]] {{.*}} 'int[2]' lvalue
+// CHECK: DeclRefExpr [[B]] {{.*}} 'int[2]' lvalue Var [[E]] 'A' 'int[2]'
+// CHECK: BinaryOperator 0x{{.*}} {{.*}} 'int[2]' lvalue '='
+// CHECK: OpaqueValueExpr [[A]] {{.*}} 'int[2]' lvalue
+// CHECK: DeclRefExpr 0x{{.*}} {{.*}} 'int[2]' lvalue Var [[E]] 'A' 'int[2]'
+// CHECK: ImplicitCastExpr 0x{{.*}} {{.*}} 'int[2]' <HLSLArrayRValue>
+// CHECK: OpaqueValueExpr [[C]] {{.*}} 'int[2]' lvalue
+// CHECK: ImplicitCastExpr [[D]] {{.*}} 'int[2]' <HLSLArrayRValue>
+// CHECK: OpaqueValueExpr [[A]] {{.*}} 'int[2]' lvalue
+// CHECK: DeclRefExpr [[B]] {{.*}} 'int[2]' lvalue Var [[E]] 'A' 'int[2]'
+export int call() {
+  int A[2] = { 0, 1 };
+  increment(A);
+  return A[0];
+}
+
+// CHECK-LABEL: fn2
+void fn2(out int Arr[2]) {
+  Arr[0] += 5;
+  Arr[1] += 6;
+}
+
+// CHECK-LABEL: call2
+// CHECK: CallExpr 0x{{.*}} {{.*}} 'void'
+// CHECK: ImplicitCastExpr 0x{{.*}} {{.*}} 'void (*)(out int[2])' <FunctionToPointerDecay>
+// CHECK: DeclRefExpr 0x{{.*}} {{.*}} 'void (out int[2])' lvalue Function 0x{{.*}} 'fn2' 'void (out int[2])'
+// CHECK: HLSLOutArgExpr 0x{{.*}} {{.*}} 'int[2]' lvalue out
+// CHECK: OpaqueValueExpr [[A:0x.*]] {{.*}} 'int[2]' lvalue
+// CHECK: DeclRefExpr [[B:0x.*]] {{.*}} 'int[2]' lvalue Var [[E:0x.*]] 'A' 'int[2]'
+// CHECK: OpaqueValueExpr [[C:0x.*]] {{.*}} 'int[2]' lvalue
+// CHECK: ImplicitCastExpr [[D:0x.*]] {{.*}} 'int[2]' <HLSLArrayRValue>
+// CHECK: OpaqueValueExpr [[A]] {{.*}} 'int[2]' lvalue
+// CHECK: DeclRefExpr [[B]] {{.*}} 'int[2]' lvalue Var [[E]] 'A' 'int[2]'
+// CHECK: BinaryOperator 0x{{.*}} {{.*}} 'int[2]' lvalue '='
+// CHECK: OpaqueValueExpr [[A]] {{.*}} 'int[2]' lvalue
+// CHECK: DeclRefExpr [[B]] {{.*}} 'int[2]' lvalue Var [[E]] 'A' 'int[2]'
+// CHECK: ImplicitCastExpr 0x{{.*}} {{.*}} 'int[2]' <HLSLArrayRValue>
+// CHECK: OpaqueValueExpr [[C]] {{.*}} 'int[2]' lvalue
+// CHECK: ImplicitCastExpr [[D]] {{.*}} 'int[2]' <HLSLArrayRValue>
+// CHECK: OpaqueValueExpr [[A]] {{.*}} 'int[2]' lvalue
+// CHECK: DeclRefExpr [[B]] {{.*}} 'int[2]' lvalue Var [[E]] 'A' 'int[2]'
+export int call2() {
+  int A[2] = { 0, 1 };
+  fn2(A);
+  return 1;
+}
diff --git a/clang/test/CodeGenHLSL/BasicFeatures/ArrayOutputArguments.hlsl b/clang/test/CodeGenHLSL/BasicFeatures/ArrayOutputArguments.hlsl
new file mode 100644
index 00000000000000..d4a5cdb9445a7f
--- /dev/null
+++ b/clang/test/CodeGenHLSL/BasicFeatures/ArrayOutputArguments.hlsl
@@ -0,0 +1,48 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-library -disable-llvm-passes -emit-llvm -finclude-default-header -o - %s | FileCheck %s
+
+// CHECK-LABEL: increment
+void increment(inout int Arr[2]) {
+  for (int I = 0; I < 2; I++)
+    Arr[0] += 2;
+}
+
+// CHECK-LABEL: call
+// CHECK: [[A:%.*]] = alloca [2 x i32], align 4
+// CHECK-NEXT: [[Tmp:%.*]] = alloca [2 x i32], align 4
+// CHECK-NEXT: [[Tmp2:%.*]] = alloca [2 x i32], align 4
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 [[A]], ptr align 4 @{{.*}}, i32 8, i1 false)
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 [[Tmp]], ptr align 4 [[A]], i32 8, i1 false)
+// CHECK-NEXT: store ptr [[Tmp]], ptr [[Tmp2]], align 4
+// CHECK-NEXT: call void @"?increment{{.*}}(ptr noalias noundef byval([2 x i32]) align 4 [[Tmp2]]) #3
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 [[A]], ptr align 4 [[Tmp]], i32 8, i1 false)
+// CHECK-NEXT: [[Idx:%.*]] = getelementptr inbounds [2 x i32], ptr [[A]], i32 0, i32 0
+// CHECK-NEXT: [[B:%.*]] = load i32, ptr [[Idx]], align 4
+// CHECK-NEXT: ret i32 [[B]]
+export int call() {
+  int A[2] = { 0, 1 };
+  increment(A);
+  return A[0];
+}
+
+// CHECK-LABEL: fn2
+void fn2(out int Arr[2]) {
+  Arr[0] += 5;
+  Arr[1] += 6;
+}
+
+// CHECK-LABEL: call2
+// CHECK: [[A:%.*]] = alloca [2 x i32], align 4
+// CHECK-NEXT: [[Tmp:%.*]] = alloca [2 x i32], align 4
+// CHECK-NEXT: [[Tmp2:%.*]] = alloca [2 x i32], align 4
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 [[A]], ptr align 4 @{{.*}}, i32 8, i1 false)
+// CHECK-NEXT: store ptr [[Tmp]], ptr [[Tmp2]], align 4
+// CHECK-NEXT: call void @"?fn2{{.*}}(ptr noalias noundef byval([2 x i32]) align 4 [[Tmp2]]) #3
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 [[A]], ptr align 4 [[Tmp]], i32 8, i1 false)
+// CHECK-NEXT: [[Idx:%.*]] = getelementptr inbounds [2 x i32], ptr [[A]], i32 0, i32 0
+// CHECK-NEXT: [[B:%.*]] = load i32, ptr [[Idx]], align 4
+// CHECK-NEXT: ret i32 [[B]]
+export int call2() {
+  int A[2] = { 0, 1 };
+  fn2(A);
+  return A[0];
+}
diff --git a/clang/test/SemaHLSL/Language/ArrayOutputArgs-errors.hlsl b/clang/test/SemaHLSL/Language/ArrayOutputArgs-errors.hlsl
new file mode 100644
index 00000000000000..46bed0d5a7cbdc
--- /dev/null
+++ b/clang/test/SemaHLSL/Language/ArrayOutputArgs-errors.hlsl
@@ -0,0 +1,51 @@
+// RUN: %clang_cc1 -finclude-default-header -triple dxil-pc-shadermodel6.6-library %s -verify
+
+void increment(inout int Arr[2]) {
+  for (int I = 0; I < 2; I++)
+    Arr[0] += 2;
+}
+
+export int wrongSize() {
+  int A[3] = { 0, 1, 2 };
+  increment(A);
+  // expected-error@-1 {{no matching function for call to 'increment'}}
+  // expected-note@*:* {{candidate function not viable: no known conversion from 'int[3]' to 'int[2]' for 1st argument}}
+  return A[0];
+}
+
+export int wrongSize2() {
+  int A[1] = { 0 };
+  increment(A);
+  // expected-error@-1 {{no matching function for call to 'increment'}}
+  // expected-note@*:* {{candidate function not viable: no known conversion from 'int[1]' to 'int[2]' for 1st argument}}
+  return A[0];
+}
+
+export void tooFewArgs() {
+  increment();
+  // expected-error@-1 {{no matching function for call to 'increment'}}
+  // expected-note@*:* {{candidate function not viable: requires single argument 'Arr', but no arguments were provided}}
+}
+
+export float wrongType() {
+  float A[2] = { 0, 1 };
+  increment(A);
+  // expected-error@-1 {{no matching function for call to 'increment'}}
+  // expected-note@*:* {{candidate function not viable: no known conversion from 'float[2]' to 'int[2]' for 1st argument}}
+  return A[0];
+}
+
+export int wrongType2() {
+  increment(5);
+  // expected-error@-1 {{no matching function for call to 'increment'}}
+  // expected-note@*:* {{candidate function not viable: no known conversion from 'int' to 'int[2]' for 1st argument}}
+  return 1;
+}
+
+export void tooManyArgs() {
+  int A[2] = { 0, 1 };
+  int B[2] = { 2, 3 };
+  increment(A, B);
+  // expected-error@-1 {{no matching function for call to 'increment'}}
+  // expected-note@*:* {{candidate function not viable: requires single argument 'Arr', but 2 arguments were provided}}
+}