https://github.com/bitcoin/bitcoin/blob/5f0c6a7b0e47e03f848dc992d37fe209dd9c6975/src/crypto/sha256.cpp#L183

This checks whether the CPU supports SSE4. It should also check if the OS supports SSE4. See this [StackOverflow answer](https://stackoverflow.com/a/22521619/6557621).
Round(a, b, c, d, e, f, g, h, 0xf2c65152ul);
    Round(h, a, b, c, d, e, f, g, 0xa88e5a6dul);
    Round(g, h, a, b, c, d, e, f, 0xb019fc65ul);
    Round(f, g, h, a, b, c, d, e, 0xb9d99ec7ul);
    Round(e, f, g, h, a, b, c, d, 0x9a1231c3ul);
    Round(d, e, f, g, h, a, b, c, 0xe70eeaa0ul);
    Round(c, d, e, f, g, h, a, b, 0xfdb1232bul);
    Round(b, c, d, e, f, g, h, a, 0xc7353eb0ul);
    Round(a, b, c, d, e, f, g, h, 0x3069bad5ul);
    Round(h, a, b, c, d, e, f, g, 0xcb976d5ful);
    Round(g, h, a, b, c, d, e, f, 0x5a0f118ful);
    Round(f, g, h, a, b, c, d, e, 0xdc1eeefdul);
    Round(e, f, g, h, a, b, c, d, 0x0a35b689ul);
    Round(d, e, f, g, h, a, b, c, 0xde0b7a04ul);
    Round(c, d, e, f, g, h, a, b, 0x58f4ca9dul);
    Round(b, c, d, e, f, g, h, a, 0xe15d5b16ul);
    Round(a, b, c, d, e, f, g, h, 0x007f3e86ul);
    Round(h, a, b, c, d, e, f, g, 0x37088980ul);
    Round(g, h, a, b, c, d, e, f, 0xa507ea32ul);
    Round(f, g, h, a, b, c, d, e, 0x6fab9537ul);
    Round(e, f, g, h, a, b, c, d, 0x17406110ul);
    Round(d, e, f, g, h, a, b, c, 0x0d8cd6f1ul);
    Round(c, d, e, f, g, h, a, b, 0xcdaa3b6dul);
    Round(b, c, d, e, f, g, h, a, 0xc0bbbe37ul);
    Round(a, b, c, d, e, f, g, h, 0x83613bdaul);
    Round(h, a, b, c, d, e, f, g, 0xdb48a363ul);
    Round(g, h, a, b, c, d, e, f, 0x0b02e931ul);
    Round(f, g, h, a, b, c, d, e, 0x6fd15ca7ul);
    Round(e, f, g, h, a, b, c, d, 0x521afacaul);
    Round(d, e, f, g, h, a, b, c, 0x31338431ul);