[Bug tree-optimization/91201] [7/8/9/10 Regression] SIMD not generated for horizontal sum of bytes in array

[bisqwit at iki dot fi]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91201

--- Comment #16 from Joel Yliluoma <bisqwit at iki dot fi> ---
In reference to my previous comment, this is the code I tested with and the
compiler flags were -Ofast -mno-avx.

        unsigned char bytes[128];
        unsigned char sum (void)
        {
          unsigned char r = 0;
          const unsigned char *p = (const unsigned char *) bytes;
          int n;
          for (n = 0; n < sizeof (bytes); ++n)
            r += p[n];
          return r;
        }