[Bug target/100093] different behavior between -mtune=cpu_type and target_attribute (“arch=cputype”)

[crazylht at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100093

--- Comment #1 from Hongtao.liu <crazylht at gmail dot com> ---
When ix86_tune_features[X86_TUNE_AVX256_UNALIGNED_LOAD/STORE_OPTIMAL] is false,
GCC goes to set up the bit MASK_AVX256_SPLIT_UNALIGNED_LOAD/STORE, but when
ix86_tune_features[X86_TUNE_AVX256_UNALIGNED_LOAD/STORE_OPTIMAL
features[X86_TUNE_AVX256_UNALIGNED_LOAD/STORE_OPTIMAL] is true, it doesn't  to
clear the bit which causes the issue.

  if (!ix86_tune_features[X86_TUNE_AVX256_UNALIGNED_LOAD_OPTIMAL]
      && !(opts_set->x_target_flags & MASK_AVX256_SPLIT_UNALIGNED_LOAD))
    opts->x_target_flags |= MASK_AVX256_SPLIT_UNALIGNED_LOAD;
  if (!ix86_tune_features[X86_TUNE_AVX256_UNALIGNED_STORE_OPTIMAL]
      && !(opts_set->x_target_flags & MASK_AVX256_SPLIT_UNALIGNED_STORE))
    opts->x_target_flags |= MASK_AVX256_SPLIT_UNALIGNED_STORE;