target sse4.1

Hey,

Would be really handy for me if this could support avx, including specifically sse4.1. Benchmarking simple simd mathematics techniques is what I’m hoping to do, to make informed decisions on simd performance.

Here’s a little test I did to see if quick-bench would help me do what I’m trying to do:

#include <x86intrin.h>

static void DPPS(benchmark::State& state) {
  __m128 left, right;
  left = _mm_set_ps(1.0f, 2.0f, 3.0f, 4.0f);
  right = _mm_set_ps(1.0f, 2.0f, 3.0f, 4.0f);
  for (auto _ : state) {
    __m128 dotted = _mm_dp_ps(left, right, 0xff);
    
    benchmark::DoNotOptimize(dotted);  
  }
  benchmark::DoNotOptimize(left);
  benchmark::DoNotOptimize(right);
}
// Register the function as a benchmark
BENCHMARK(DPPS);

static void MULHADD(benchmark::State& state) {
  __m128 left, right;
  left = _mm_set_ps(1.0f, 2.0f, 3.0f, 4.0f);
  right = _mm_set_ps(1.0f, 2.0f, 3.0f, 4.0f);
  for (auto _ : state) {
    __m128 dotted = _mm_mul_ps(left, right);
    dotted = _mm_hadd_ps(dotted, dotted);
    dotted = _mm_hadd_ps(dotted, dotted);
    
    benchmark::DoNotOptimize(dotted);  
  }
  benchmark::DoNotOptimize(left);
  benchmark::DoNotOptimize(right);
}
BENCHMARK(MULHADD);

The errors generated:

Error or timeout
bench-file.cpp:9:21: error: '__builtin_ia32_dpps' needs target feature sse4.1
    __m128 dotted = _mm_dp_ps(left, right, 0xff);
                    ^
/usr/lib/clang/5.0.0/include/smmintrin.h:620:12: note: expanded from macro '_mm_dp_ps'
  (__m128) __builtin_ia32_dpps((__v4sf)(__m128)(X), \
           ^
bench-file.cpp:26:14: error: always_inline function '_mm_hadd_ps' requires target feature 'sse3', but would be inlined into function 'MULHADD' that is compiled without support for 'sse3'
    dotted = _mm_hadd_ps(dotted, dotted);
             ^
bench-file.cpp:27:14: error: always_inline function '_mm_hadd_ps' requires target feature 'sse3', but would be inlined into function 'MULHADD' that is compiled without support for 'sse3'
    dotted = _mm_hadd_ps(dotted, dotted);
             ^
3 errors generated.

Cheers

[ZongyiZhou]

@FredTingaud You can try adding “-march native” to the compiler options.

[xoorath]

Running into this again 4 years later, so I’m back to +1 my own issue. 😃

This time I’m trying to benchmark __popcnt against other methods of counting bits in an integer.