[Bug target/121970] struct copy still use zmm even specify -mmove-max=256

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121970

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |target
           Keywords|                            |missed-optimization

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Hongtao Liu from comment #1)
> Although the option is x86 specific, but I think the issue is middle-end,
> it's related how MOVE_MAX and STORE_MAX_PIECES is used.

#define MOVE_MAX \
  ((TARGET_AVX512F \
    && (ix86_move_max == PVW_AVX512 \
        || ix86_store_max == PVW_AVX512)) \
   ? 64 \
   : ((TARGET_AVX \
       && (ix86_move_max >= PVW_AVX256 \
           || ix86_store_max >= PVW_AVX256)) \
      ? 32 \
      : ((TARGET_SSE2 \
          && TARGET_SSE_UNALIGNED_LOAD_OPTIMAL \
          && TARGET_SSE_UNALIGNED_STORE_OPTIMAL) \
         ? 16 : UNITS_PER_WORD)))


x86 defines MOVE_MAX based on if either option is set to 512 here. 

While STORE_MAX_PIECES is defined by store max only:

#define STORE_MAX_PIECES \
  (TARGET_INTER_UNIT_MOVES_TO_VEC \
   ? ((TARGET_AVX512F && ix86_store_max == PVW_AVX512) \
      ? 64 \
      : ((TARGET_AVX \
          && ix86_store_max >= PVW_AVX256) \
          ? 32 \
          : ((TARGET_SSE2 \
              && TARGET_SSE_UNALIGNED_STORE_OPTIMAL) \
              ? 16 : UNITS_PER_WORD))) \
   : UNITS_PER_WORD)


So this seems like a target issue.