[randy408]

This is what I use for benchmarking: https://github.com/libspng/spngt, my platform is Debian 10, GCC 8.3.0 with -O3 on an i5-4670. I use -SPNG_SSE=2 because that targets SSE2 instead of SSSE3, this matches the Debian build of libpng, both are linked against zlib-ng. The results I get for medium_rgb(a)8.png and large_palette.png are the results on the charts.

[Ono-Sendai]

What version of LibPNG are you comparing against? I am using LibPNG 1.635. Note that recent versions of LibPNG have some SSE optimisations contributed from Intel.

[randy408]

I'm using 1.6.36, the most obvious speedups should come from RGBA 8-bit PNG's, that codepath doesn't rely on compiler optimizations.