change clamp templates so they call clamp instead of __builtin_hlsl_elementwise_clamp, to ensure clamp can't be called on 16 bit types in a shader model before 6.2. Add tests to show this

Author: spall

clang/lib/Headers/hlsl/hlsl_compat_overloads.h

@@ -25,38 +25,34 @@ template <typename T, typename R, typename U, uint N>
 constexpr __detail::enable_if_t<
     __detail::is_arithmetic<U>::Value && (N > 1 && N <= 4), vector<T, N>>
 clamp(vector<T, N> p0, vector<R, N> p1, U p2) {
-  return __builtin_hlsl_elementwise_clamp(p0, (vector<T, N>)p1,
-                                          (vector<T, N>)p2);
+  return clamp(p0, (vector<T, N>)p1, (vector<T, N>)p2);
 }
 template <typename T, typename R, typename U, uint N>
 constexpr __detail::enable_if_t<
     __detail::is_arithmetic<U>::Value && (N > 1 && N <= 4), vector<T, N>>
 clamp(vector<T, N> p0, U p1, vector<R, N> p2) {
-  return __builtin_hlsl_elementwise_clamp(p0, (vector<T, N>)p1,
-                                          (vector<T, N>)p2);
+  return clamp(p0, (vector<T, N>)p1, (vector<T, N>)p2);
 }
 template <typename T, typename U, typename V, uint N>
 constexpr __detail::enable_if_t<__detail::is_arithmetic<U>::Value &&
                                     __detail::is_arithmetic<V>::Value &&
                                     (N > 1 && N <= 4),
                                 vector<T, N>>
 clamp(vector<T, N> p0, U p1, V p2) {
-  return __builtin_hlsl_elementwise_clamp(p0, (vector<T, N>)p1,
-                                          (vector<T, N>)p2);
+  return clamp(p0, (vector<T, N>)p1, (vector<T, N>)p2);
 }
 template <typename T, typename R, typename S, uint N>
 constexpr __detail::enable_if_t<(N > 1 && N <= 4), vector<T, N>>
 clamp(vector<T, N> p0, vector<R, N> p1, vector<S, N> p2) {
-  return __builtin_hlsl_elementwise_clamp(p0, (vector<T, N>)p1,
-                                          (vector<T, N>)p2);
+  return clamp(p0, (vector<T, N>)p1, (vector<T, N>)p2);
 }
 template <typename U, typename V, typename W>
 constexpr __detail::enable_if_t<__detail::is_arithmetic<U>::Value &&
                                     __detail::is_arithmetic<V>::Value &&
                                     __detail::is_arithmetic<W>::Value,
                                 U>
 clamp(U p0, V p1, W p2) {
-  return __builtin_hlsl_elementwise_clamp(p0, (U)p1, (U)p2);
+  return clamp(p0, (U)p1, (U)p2);
 }
 
 } // namespace hlsl

clang/test/SemaHLSL/BuiltIns/clamp-errors-16bit.hlsl

@@ -0,0 +1,27 @@
+// RUN: not %clang_dxc -enable-16bit-types -T cs_6_0 -HV 202x %s 2>&1  | FileCheck %s
+
+// check we error on 16 bit type if shader model is too old
+// CHECK: '-enable-16bit-types' option requires target HLSL Version >= 2018 and shader model >= 6.2, but HLSL Version is 'hlsl202x' and shader model is '6.0'
+int16_t test_int16_t_error(int16_t p0, int p1) {
+  return clamp(p0, p0, p1);
+}
+
+int16_t3 test_int16_t3_error(int16_t3 p0, int3 p1) {
+  return clamp(p0, p0, p1);
+}
+
+half test_half_error(half p0, int p1) {
+  return clamp(p0, p1, p1);
+}
+
+half3 test_half3_error(half3 p0, int3 p1) {
+  return clamp(p0, p0, p1);
+}
+
+uint16_t test_uint16_t_error(uint16_t p0, int p1) {
+  return clamp(p0, p0, p1);
+}
+
+uint16_t3 test_uint16_t3_error(uint16_t3 p0, int3 p1) {
+  return clamp(p0, p1, p1);
+}