Fix HIP build of tests/deduction.cu

Author: stijnh

tests/deduction.cu

@@ -3,8 +3,10 @@
 #include "common.h"
 #include "kernel_float/prelude.h"
 
-// Class template argument deduction. These checks are compile-time only: if this file compiles,
-// they pass. The file is valid as both C++17 and C++20.
+// Class template argument deduction. These tests run on host only: a bug in clang (HIP)
+// treats deduction guides as host functions, so CTAD cannot be used in device code.
+// See https://github.com/llvm/llvm-project/issues/146646 (fixed in LLVM 22 by
+// https://github.com/llvm/llvm-project/pull/170481).
 
 namespace deduction_tests {
 using namespace kernel_float::prelude;
@@ -13,35 +15,37 @@ struct packed3 {
     float x, y, z;  // sizeof(packed3) != alignof(packed3)
 };
 
-__host__ __device__ void class_templates(float* fp, const packed3* cp) {
+TEST_CASE("deduction guides") {
+    float* fp = nullptr;
+    const packed3* cp = nullptr;
+
     kf::vector v(1, 2.0f);
-    static_assert(std::is_same<decltype(v), kf::vec<float, 2>>::value, "");
+    STATIC_REQUIRE(std::is_same_v<decltype(v), kf::vec<float, 2>>);
 
     kf::vector_ptr p(fp);
-    static_assert(
-        std::is_same<decltype(p), kf::vector_ptr<float, 1, kf::access_policy<float>>>::value,
-        "");
+    STATIC_REQUIRE(std::is_same_v<decltype(p), kf::vector_ptr<float, 1, kf::access_policy<float>>>);
 
     kf::vector_ptr q(cp);
-    using expected_q = kf::vector_ptr<packed3, 1, kf::access_policy<const packed3>>;
-    static_assert(std::is_same<decltype(q), expected_q>::value, "");
+    STATIC_REQUIRE(
+        std::is_same_v<decltype(q), kf::vector_ptr<packed3, 1, kf::access_policy<const packed3>>>);
 
     kf::constant c(2.0);
-    static_assert(std::is_same<decltype(c), kf::constant<double>>::value, "");
+    STATIC_REQUIRE(std::is_same_v<decltype(c), kf::constant<double>>);
+    CHECK(c.get() == 2.0);
 }
 
 // From C++20, the compiler derives deduction guides for alias templates from those of the class
 // template they name.
 #if __cplusplus >= 202002L
-__host__ __device__ void alias_templates() {
+TEST_CASE("deduction guides for alias templates") {
     kf::scalar s(1.5);
-    static_assert(std::is_same<decltype(s), kf::scalar<double>>::value, "");
+    STATIC_REQUIRE(std::is_same_v<decltype(s), kf::scalar<double>>);
 
     kscalar ks(1.5f);
-    static_assert(std::is_same<decltype(ks), kscalar<float>>::value, "");
+    STATIC_REQUIRE(std::is_same_v<decltype(ks), kscalar<float>>);
 
     kconstant kc(2.0);
-    static_assert(std::is_same<decltype(kc), kconstant<double>>::value, "");
+    STATIC_REQUIRE(std::is_same_v<decltype(kc), kconstant<double>>);
 }
 #endif
 }  // namespace deduction_tests