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#include "Halide.h"
#include "halide_benchmark.h"
#include "halide_test_dirs.h"
#include <algorithm>
#include <cstdio>
using namespace Halide;
using namespace Halide::Tools;
Buffer<uint16_t> input;
Buffer<uint16_t> output;
#define MIN 1
#define MAX 1020
double test(Func f, bool test_correctness = true) {
f.compile_to_assembly(Internal::get_test_tmp_dir() + f.name() + ".s", {input}, f.name());
f.compile_jit();
f.realize(output);
if (test_correctness) {
for (int y = 0; y < output.height(); y++) {
for (int x = 0; x < output.width(); x++) {
int ix1 = std::max(std::min(x, MAX), MIN);
int ix2 = std::max(std::min(x + 1, MAX), MIN);
uint16_t correct = input(ix1, y) * 3 + input(ix2, y);
if (output(x, y) != correct) {
printf("output(%d, %d) = %d instead of %d\n",
x, y, output(x, y), correct);
exit(1);
}
}
}
}
return benchmark([&]() { f.realize(output); });
}
int main(int argc, char **argv) {
Target target = get_jit_target_from_environment();
if (target.arch == Target::WebAssembly) {
printf("[SKIP] Performance tests are meaningless and/or misleading under WebAssembly interpreter.\n");
return 0;
}
// Try doing vector loads with a boundary condition in various
// ways and compare the performance.
input = Buffer<uint16_t>(1024 + 8, 320);
for (int y = 0; y < input.height(); y++) {
for (int x = 0; x < input.width(); x++) {
input(x, y) = rand() & 0xfff;
}
}
output = Buffer<uint16_t>(1024, 320);
Var x, y;
double t_ref, t_clamped, t_scalar, t_pad;
{
// Do an unclamped load to get a reference number
Func f;
f(x, y) = input(x, y) * 3 + input(x + 1, y);
f.vectorize(x, 8);
t_ref = test(f, false);
}
{
// Variant 1 - do the clamped vector load
Func g;
g(x, y) = input(clamp(x, MIN, MAX), y);
Func f;
f(x, y) = g(x, y) * 3 + g(x + 1, y);
f.vectorize(x, 8);
f.compile_to_lowered_stmt(Internal::get_test_tmp_dir() + "debug_clamped_vector_load.stmt", f.infer_arguments());
t_clamped = test(f);
}
{
// Variant 2 - do the load as a scalar op just before the vectorized stuff
Func g;
g(x, y) = input(clamp(x, MIN, MAX), y);
Func f;
f(x, y) = g(x, y) * 3 + g(x + 1, y);
f.vectorize(x, 8);
g.compute_at(f, x);
t_scalar = test(f);
}
{
// Variant 3 - pad each scanline using scalar code
Func g;
g(x, y) = input(clamp(x, MIN, MAX), y);
Func f;
f(x, y) = g(x, y) * 3 + g(x + 1, y);
f.vectorize(x, 8);
g.compute_at(f, y);
t_pad = test(f);
}
// This constraint is pretty lax, because the op is so trivial
// that the overhead of branching is large. For more complex ops,
// the overhead should be smaller. We just make sure it's faster
// than scalarizing or padding.
if (t_clamped > t_scalar || t_clamped > t_pad) {
printf("Clamped load timings suspicious:\n"
"Unclamped: %f\n"
"Clamped: %f\n"
"Scalarize the load: %f\n"
"Pad the input: %f\n",
t_ref, t_clamped, t_scalar, t_pad);
return 1;
}
printf("Success!\n");
// Clean up our global images, otherwise you get destructor
// order weirdness. The images hold onto the JIT-compiled module
// that created them, and will delete it when they die. However,
// it might not be possible to destroy the module cleanly after
// main exits, because destroying the module touches globals
// inside of llvm, and destructor order of globals is not
// guaranteed.
input = Buffer<uint16_t>();
output = Buffer<uint16_t>();
return 0;
}
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