text: #include "Halide.h"
  #include <future>
  #include <stdio.h>
  
  using namespace Halide;
  
  template<typename A>
  const char *string_of_type();
  
  #define DECL_SOT(name)                   \
      template<>                           \
      const char *string_of_type<name>() { \
          return #name;                    \
      }
  
  DECL_SOT(uint8_t);
  DECL_SOT(int8_t);
  DECL_SOT(uint16_t);
  DECL_SOT(int16_t);
  DECL_SOT(uint32_t);
  DECL_SOT(int32_t);
  DECL_SOT(float);
  DECL_SOT(double);
  
  template<typename T>
  bool is_type_supported(int vec_width, const Target &target) {
      DeviceAPI device = DeviceAPI::Default_GPU;
  
      if (target.features_any_of({Target::HVX_64, Target::HVX_128})) {
          device = DeviceAPI::Hexagon;
      }
      return target.supports_type(type_of<T>().with_lanes(vec_width), device);
  }
  
  template<typename A, typename B>
  bool test(int vec_width, const Target &target) {
      if (!is_type_supported<A>(vec_width, target) || !is_type_supported<B>(vec_width, target)) {
          // Type not supported, return pass.
          return true;
      }
  
      int W = 1024;
      int H = 1;
  
      Buffer<A> input(W, H);
      for (int y = 0; y < H; y++) {
          for (int x = 0; x < W; x++) {
              // Casting from an out-of-range float to an int is UB, so
              // we have to pick our values a little carefully.
              input(x, y) = (A)((rand() & 0xffff) / 512.0);
          }
      }
  
      Var x, y;
      Func f;
  
      f(x, y) = cast<B>(input(x, y));
  
      if (target.has_gpu_feature()) {
          Var xo, xi;
          f.gpu_tile(x, xo, xi, 64);
      } else {
          if (target.features_any_of({Target::HVX_64, Target::HVX_128})) {
              // TODO: Non-native vector widths hang the compiler here.
              //f.hexagon();
          }
          if (vec_width > 1) {
              f.vectorize(x, vec_width);
          }
      }
  
      Buffer<B> output = f.realize(W, H);
  
      /*
      for (int y = 0; y < H; y++) {
          for (int x = 0; x < W; x++) {
              printf("%d %d -> %d %d\n", x, y, (int)(input(x, y)), (int)(output(x, y)));
          }
      }
      */
  
      for (int y = 0; y < H; y++) {
          for (int x = 0; x < W; x++) {
  
              bool ok = ((B)(input(x, y)) == output(x, y));
  
              if (!ok) {
                  fprintf(stderr, "%s x %d -> %s x %d failed\n",
                          string_of_type<A>(), vec_width,
                          string_of_type<B>(), vec_width);
                  fprintf(stderr, "At %d %d, %f -> %f instead of %f\n",
                          x, y,
                          (double)(input(x, y)),
                          (double)(output(x, y)),
                          (double)((B)(input(x, y))));
                  return false;
              }
          }
      }
  
      return true;
  }
  
  template<typename A>
  bool test_all(int vec_width, const Target &target) {
      bool success = true;
      success = success && test<A, float>(vec_width, target);
      success = success && test<A, double>(vec_width, target);
      success = success && test<A, uint8_t>(vec_width, target);
      success = success && test<A, uint16_t>(vec_width, target);
      success = success && test<A, uint32_t>(vec_width, target);
      success = success && test<A, int8_t>(vec_width, target);
      success = success && test<A, int16_t>(vec_width, target);
      success = success && test<A, int32_t>(vec_width, target);
      return success;
  }
  
  int main(int argc, char **argv) {
  // TODO: is this still relevant?
  // We don't test this on windows, because float-to-int conversions
  // on windows use _ftol2, which has its own unique calling
  // convention, and older LLVMs (e.g. pnacl) don't do it right so
  // you get clobbered registers.
  #ifdef WIN32
      printf("[SKIP] float-to-int conversions don't work with older LLVMs on Windows\n");
      return 0;
  #endif
  
      Target target = get_jit_target_from_environment();
  
      // We only test power-of-two vector widths for now
      Halide::Internal::ThreadPool<bool> pool;
      std::vector<std::future<bool>> futures;
      int vec_width_max = 64;
      if (target.arch == Target::WebAssembly) {
          // The wasm jit is very slow, so shorten this test here.
          vec_width_max = 16;
      }
      for (int vec_width = 1; vec_width <= vec_width_max; vec_width *= 2) {
          futures.push_back(pool.async([=]() {
              bool success = true;
              success = success && test_all<float>(vec_width, target);
              success = success && test_all<double>(vec_width, target);
              success = success && test_all<uint8_t>(vec_width, target);
              success = success && test_all<uint16_t>(vec_width, target);
              success = success && test_all<uint32_t>(vec_width, target);
              success = success && test_all<int8_t>(vec_width, target);
              success = success && test_all<int16_t>(vec_width, target);
              success = success && test_all<int32_t>(vec_width, target);
              return success;
          }));
      }
  
      bool ok = true;
      for (auto &f : futures) {
          ok &= f.get();
      }
  
      if (!ok) return -1;
      printf("Success!\n");
      return 0;
  }
  