[Bug target/126959] -march=znver4 prefers load from memory for mask register

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126959

--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> ---
The bug is in ix86_preferred_reload_class:

  /* All classes can load zeros.  */
  if (x == CONST0_RTX (mode))
    return regclass;

  /* Force constants into memory if we are loading a (nonzero) constant into
     an MMX, SSE or MASK register.  This is because there are no MMX/SSE/MASK
     instructions to load from a constant.  */
  if (CONSTANT_P (x)
      && (MAYBE_MMX_CLASS_P (regclass)
          || MAYBE_SSE_CLASS_P (regclass)
          || MAYBE_MASK_CLASS_P (regclass)))
    return NO_REGS;

-1 should be allowed for SSE and MASK registers.