rb_str_buf_append: add a fast path for ENC_CODERANGE_VALID
If the RHS has valid encoding, and both strings have the same encoding, we can use the fast path.
However we need to update the LHS coderange.
compare-ruby: ruby 3.2.0dev (2022-07-21T14:46:32Z master cdbb9b8555) [arm64-darwin21] built-ruby: ruby 3.2.0dev (2022-07-25T07:25:41Z string-concat-vali.. 11a2772bdd) [arm64-darwin21] warming up... | |compare-ruby|built-ruby| |:-------------------|-----------:|---------:| |binary_concat_7bit | 554.816k| 556.460k| | | -| 1.00x| |utf8_concat_7bit | 556.367k| 555.101k| | | 1.00x| -| |utf8_concat_UTF8 | 412.555k| 556.824k| | | -| 1.35x|
Added by byroot (Jean Boussier) almost 3 years ago
rb_str_buf_append: add a fast path for ENC_CODERANGE_VALID
If the RHS has valid encoding, and both strings have the same
encoding, we can use the fast path.
However we need to update the LHS coderange.