[Bug tree-optimization/115843] [14/15 Regression] 531.deepsjeng_r fails to verify with -O3 -march=znver4 --param vect-partial-vector-usage=2

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115843

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
The following fails with -O3 -mavx512vl --param vect-partial-vector-usage=2
-mtune=znver4 -mprefer-vector-width=512 but succeeds with -mtune=cascadelake.

typedef __UINT64_TYPE__ BITBOARD;
BITBOARD KingPressureMask1[64], KingSafetyMask1[64];

void __attribute__((noinline))
foo()
{
  int i;

  for (i = 0; i < 64; i++) {
      if ((i & 7) == 0) {
          KingPressureMask1[i] = KingSafetyMask1[i + 1];
      } else if ((i & 7) == 7) {
          KingPressureMask1[i] = KingSafetyMask1[i - 1];
      } else {
          KingPressureMask1[i] = KingSafetyMask1[i];
      }
  }
}

BITBOARD verify[64] = {1, 1, 2, 3, 4, 5, 6, 6, 9, 9, 10, 11, 12, 13, 14, 14,
17, 17, 18, 19, 
  20, 21, 22, 22, 25, 25, 26, 27, 28, 29, 30, 30, 33, 33, 34, 35, 36, 37, 38, 
  38, 41, 41, 42, 43, 44, 45, 46, 46, 49, 49, 50, 51, 52, 53, 54, 54, 57, 57, 
  58, 59, 60, 61, 62, 62};

int main()
{
  for (int i = 0; i < 64; ++i)
    KingSafetyMask1[i] = i;
  foo ();
  for (int i = 0; i < 64; ++i)
    if (KingPressureMask1[i] != verify[i])
      __builtin_abort ();
  return 0;
}