[SYCL][NFC] Rewrite some LIT tests to unittests (#15783)

The intent is to optimize our testing suite by avoiding device compilation where it isn't necessary

---------

Patch-by: Alexey Sachkov <[email protected]>
Co-authored-by: Marcos Maronas <[email protected]>

Author: uditagarwal97

sycl/test/basic_tests/accessor/zero-dim-host-accessor.cpp

@@ -0,0 +1,81 @@
+#include <sycl/ext/oneapi/bfloat16.hpp>
+#include <sycl/sycl.hpp>
+
+#include <gtest/gtest.h>
+
+#include <cmath>
+#include <limits>
+#include <string>
+
+namespace {
+// Helper to convert the expected bits to float value to compare with the result.
+typedef union {
+  float Value;
+  struct {
+    uint32_t Mantissa : 23;
+    uint32_t Exponent : 8;
+    uint32_t Sign : 1;
+  } RawData;
+} floatConvHelper;
+
+float bitsToFloatConv(std::string Bits) {
+  floatConvHelper Helper;
+  Helper.RawData.Sign = static_cast<uint32_t>(Bits[0] - '0');
+  uint32_t Exponent = 0;
+  for (size_t I = 1; I != 9; ++I)
+    Exponent = Exponent + static_cast<uint32_t>(Bits[I] - '0') * std::pow(2, 8 - I);
+  Helper.RawData.Exponent = Exponent;
+  uint32_t Mantissa = 0;
+  for (size_t I = 9; I != 32; ++I)
+    Mantissa = Mantissa + static_cast<uint32_t>(Bits[I] - '0') * std::pow(2, 31 - I);
+  Helper.RawData.Mantissa = Mantissa;
+  return Helper.Value;
+}
+} // namespace
+
+TEST(BFloat16, BF16FromFloat) {
+  sycl::ext::oneapi::bfloat16 B = 0.0f;
+  auto Result = sycl::bit_cast<uint16_t>(B);
+  ASSERT_EQ(Result, std::stoi("0000000000000000", nullptr, 2));
+
+  B = 42.0f;
+  Result = sycl::bit_cast<uint16_t>(B);
+  ASSERT_EQ(Result, std::stoi("100001000101000", nullptr, 2));
+
+  B = std::numeric_limits<float>::min();
+  Result = sycl::bit_cast<uint16_t>(B);
+  ASSERT_EQ(Result, std::stoi("0000000010000000", nullptr, 2));
+
+  B = std::numeric_limits<float>::max();
+  Result = sycl::bit_cast<uint16_t>(B);
+  ASSERT_EQ(Result, std::stoi("0111111110000000", nullptr, 2));
+
+  B = std::numeric_limits<float>::quiet_NaN();
+  Result = sycl::bit_cast<uint16_t>(B);
+  ASSERT_EQ(Result, std::stoi("1111111111000001", nullptr, 2));
+}
+
+TEST(BFloat16, BF16ToFloat) {
+  // See https://float.exposed/b0xffff
+  uint16_t V = 0;
+  float Res = sycl::bit_cast<sycl::ext::oneapi::bfloat16>(V);
+  ASSERT_EQ(Res,
+            bitsToFloatConv(std::string("00000000000000000000000000000000")));
+
+  V = 1;
+  Res = sycl::bit_cast<sycl::ext::oneapi::bfloat16>(V);
+  ASSERT_EQ(Res,
+            bitsToFloatConv(std::string("00000000000000010000000000000000")));
+
+  V = 42;
+  Res = sycl::bit_cast<sycl::ext::oneapi::bfloat16>(V);
+  ASSERT_EQ(Res,
+            bitsToFloatConv(std::string("00000000001010100000000000000000")));
+
+  // std::numeric_limits<uint16_t>::max() - 0xffff is bfloat16 -Nan and
+  // -Nan == -Nan check in check_bf16_to_float would fail, so use not Nan:
+  V = 65407;
+  Res = sycl::bit_cast<sycl::ext::oneapi::bfloat16>(V);
+  ASSERT_EQ(Res,
+            bitsToFloatConv(std::string("11111111011111110000000000000000")));
+}

sycl/test/extensions/bfloat16_host.cpp

@@ -17,6 +17,7 @@ add_sycl_unittest(ExtensionsTests OBJECT
   NoDeviceIPVersion.cpp
   WorkGroupMemoryBackendArgument.cpp
   GetLastEvent.cpp
+  BFloat16.cpp
 )
 
 add_subdirectory(CommandGraph)

sycl/unittests/Extensions/BFloat16.cpp

@@ -8,4 +8,5 @@ add_sycl_unittest(AccessorTests OBJECT
   HostAccessorReverseIterator.cpp
   LocalAccessorDefaultCtor.cpp
   RuntimeProperties.cpp
+  HostAccessor.cpp
 )

sycl/unittests/Extensions/CMakeLists.txt

@@ -0,0 +1,18 @@
+#include <sycl/sycl.hpp>
+
+#include <gtest/gtest.h>
+
+TEST(HostAccessor, ZeroDimAccessor) {
+  using DataT = int;
+  using AccT = sycl::host_accessor<DataT, 0>;
+
+  DataT data = 42;
+  sycl::buffer<DataT, 1> data_buf(&data, sycl::range<1>(1));
+  AccT acc = {data_buf};
+
+  ASSERT_EQ(acc.get_size(), sizeof(DataT));
+  ASSERT_EQ(acc.size(), static_cast<size_t>(1));
+
+  DataT &ref = acc;
+  ASSERT_EQ(ref, data);
+}