diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 3e0e9bb5e39e5..dca9d6e7ea358 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -15944,6 +15944,20 @@ ExprResult Sema::CreateBuiltinUnaryOp(SourceLocation OpLoc,
             return ExprError(Diag(OpLoc, diag::err_typecheck_unary_expr)
                              << resultType << Input.get()->getSourceRange());
         }
+      } else if (Context.getLangOpts().HLSL && resultType->isVectorType() &&
+                 !resultType->hasBooleanRepresentation()) {
+        // HLSL unary logical 'not' behaves like C++, which states that the
+        // operand is converted to bool and the result is bool, however HLSL
+        // extends this property to vectors.
+        const VectorType *VTy = resultType->castAs<VectorType>();
+        resultType =
+            Context.getExtVectorType(Context.BoolTy, VTy->getNumElements());
+
+        Input = ImpCastExprToType(
+                    Input.get(), resultType,
+                    ScalarTypeToBooleanCastKind(VTy->getElementType()))
+                    .get();
+        break;
       } else if (resultType->isExtVectorType()) {
         if (Context.getLangOpts().OpenCL &&
             Context.getLangOpts().getOpenCLCompatibleVersion() < 120) {
diff --git a/clang/test/CodeGenHLSL/Operators/logical-not.hlsl b/clang/test/CodeGenHLSL/Operators/logical-not.hlsl
new file mode 100644
index 0000000000000..0f9d0677d8610
--- /dev/null
+++ b/clang/test/CodeGenHLSL/Operators/logical-not.hlsl
@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.6-library -disable-llvm-passes -emit-llvm -finclude-default-header -fnative-half-type -o - %s | FileCheck %s
+
+// CHECK-LABEL: case1
+// CHECK: [[ToBool:%.*]] = icmp ne <2 x i32> {{.*}}, zeroinitializer
+// CHECK-NEXT: [[BoolCmp:%.*]] = icmp eq <2 x i1> [[ToBool]], zeroinitializer
+// CHECK-NEXT: {{.*}} = zext <2 x i1> [[BoolCmp]] to <2 x i32>
+export uint32_t2 case1(uint32_t2 b) {
+    return !b;
+}
+
+// CHECK-LABEL: case2
+// CHECK: [[ToBool:%.*]] = icmp ne <3 x i32> {{.*}}, zeroinitializer
+// CHECK-NEXT: [[BoolCmp:%.*]] = icmp eq <3 x i1> [[ToBool]], zeroinitializer
+// CHECK-NEXT: {{.*}} = zext <3 x i1> [[BoolCmp]] to <3 x i32>
+export int32_t3 case2(int32_t3 b) {
+    return !b;
+}
+
+// CHECK-LABEL: case3
+// CHECK: [[ToBool:%.*]] = fcmp reassoc nnan ninf nsz arcp afn une half {{.*}}, 0xH0000
+// CHECK-NEXT: [[BoolCmp:%.*]] = xor i1 [[ToBool]], true
+// CHECK-NEXT: {{.*}} = uitofp i1 [[BoolCmp]] to half
+export float16_t case3(float16_t b) {
+    return !b;
+}
+
+// CHECK-LABEL: case4
+// CHECK: [[ToBool:%.*]] = fcmp reassoc nnan ninf nsz arcp afn une <4 x float> {{.*}}, zeroinitializer
+// CHECK-NEXT: [[BoolCmp:%.*]] = icmp eq <4 x i1> [[ToBool]], zeroinitializer
+// CHECK-NEXT: {{.*}} = uitofp <4 x i1> [[BoolCmp]] to <4 x float>
+export float4 case4(float4 b) {
+    return !b;
+}
diff --git a/clang/test/SemaHLSL/Operators/logical-not.hlsl b/clang/test/SemaHLSL/Operators/logical-not.hlsl
new file mode 100644
index 0000000000000..d06ca3982be05
--- /dev/null
+++ b/clang/test/SemaHLSL/Operators/logical-not.hlsl
@@ -0,0 +1,53 @@
+// RUN: %clang_cc1 -finclude-default-header -triple  dxil-pc-shadermodel6.6-library %s -fnative-half-type -ast-dump -ast-dump-filter=case | FileCheck %s
+
+// CHECK-LABEL: FunctionDecl {{.*}} used case1 'uint32_t2 (uint32_t2)'
+// CHECK-NEXT: ParmVarDecl {{.*}} used b 'uint32_t2':'vector<uint32_t, 2>'
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: ReturnStmt
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'vector<uint32_t, 2>' <IntegralCast>
+// CHECK-NEXT: UnaryOperator {{.*}} 'vector<bool, 2>' prefix '!' cannot overflow
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'vector<bool, 2>' <IntegralToBoolean>
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'uint32_t2':'vector<uint32_t, 2>' <LValueToRValue>
+// CHECK-NEXT: DeclRefExpr {{.*}} 'uint32_t2':'vector<uint32_t, 2>' lvalue ParmVar {{.*}} 'b' 'uint32_t2':'vector<uint32_t, 2>'
+export uint32_t2 case1(uint32_t2 b) {
+    return !b;
+}
+
+// CHECK-LABEL: FunctionDecl {{.*}} used case2 'int32_t3 (int32_t3)'
+// CHECK-NEXT: ParmVarDecl {{.*}} used b 'int32_t3':'vector<int32_t, 3>'
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: ReturnStmt
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'vector<int32_t, 3>' <IntegralCast>
+// CHECK-NEXT: UnaryOperator {{.*}} 'vector<bool, 3>' prefix '!' cannot overflow
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'vector<bool, 3>' <IntegralToBoolean>
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'int32_t3':'vector<int32_t, 3>' <LValueToRValue>
+// CHECK-NEXT: DeclRefExpr {{.*}} 'int32_t3':'vector<int32_t, 3>' lvalue ParmVar {{.*}} 'b' 'int32_t3':'vector<int32_t, 3>'
+export int32_t3 case2(int32_t3 b) {
+    return !b;
+}
+
+// CHECK-LABEL: FunctionDecl {{.*}} used case3 'float16_t (float16_t)'
+// CHECK-NEXT: ParmVarDecl {{.*}} used b 'float16_t':'half'
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: ReturnStmt
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'float16_t':'half' <IntegralToFloating>
+// CHECK-NEXT: UnaryOperator {{.*}} 'bool' prefix '!' cannot overflow
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'bool' <FloatingToBoolean>
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'float16_t':'half' <LValueToRValue>
+// CHECK-NEXT: DeclRefExpr {{.*}} 'float16_t':'half' lvalue ParmVar {{.*}} 'b' 'float16_t':'half'
+export float16_t case3(float16_t b) {
+    return !b;
+}
+
+// CHECK-LABEL: FunctionDecl {{.*}} used case4 'float4 (float4)'
+// CHECK-NEXT: ParmVarDecl {{.*}} used b 'float4':'vector<float, 4>'
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: ReturnStmt
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'vector<float, 4>' <IntegralToFloating>
+// CHECK-NEXT: UnaryOperator {{.*}} 'vector<bool, 4>' prefix '!' cannot overflow
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'vector<bool, 4>' <FloatingToBoolean>
+// CHECK-NEXT: ImplicitCastExpr {{.*}} 'float4':'vector<float, 4>' <LValueToRValue>
+// CHECK-NEXT: DeclRefExpr {{.*}} 'float4':'vector<float, 4>' lvalue ParmVar {{.*}} 'b' 'float4':'vector<float, 4>'
+export float4 case4(float4 b) {
+    return !b;
+}