[Bug tree-optimization/51492] vectorizer does not support saturated arithmetic patterns

[pan2.li at intel dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51492

--- Comment #7 from Li Pan <pan2.li at intel dot com> ---
RISC-V backend reproduce code, build with "-march=rv64gcv_zba_zbb_zbc_zbs
--param=riscv-autovec-preference=fixed-vlmax -Ofast -ffast-math"

typedef unsigned short uint16_t;

void AAA (uint16_t *x, uint16_t *y, unsigned wsize, unsigned count)
{
  unsigned m = 0, n = count;
  register uint16_t *p;

  p = x;

  do {
    m = *--p;
    *p = (uint16_t)(m >= wsize ? m-wsize : 0);
  } while (--n);

  n = wsize;
  p = y;

  do {
      m = *--p;
      *p = (uint16_t)(m >= wsize ? m-wsize : 0);
  } while (--n);
}