Microbenchmark:

importpyperfimport_testcapistr1="a"*10str2=str1.encode().decode()ifstr2isstr1:raiseExceptionrunner=pyperf.Runner()runner.bench_time_func('_PyUnicode_EQ',_testcapi.bench_eq,str1,str2)runner.bench_time_func('_PyUnicode_Equal',_testcapi.bench__equal,str1,str2)

Result on Python built with PGO+LTO (without CPU isolation):

_PyUnicode_EQ: Mean +- std dev: 7.45 ns +- 0.02 ns_PyUnicode_Equal: Mean +- std dev: 7.44 ns +- 0.02 ns

The performance is the same.

cc@serhiy-storchaka

For comparison, results on the main branch, also with PGO+LTO:

_PyUnicode_EQ: Mean +- std dev: 8.52 ns +- 0.02 ns_PyUnicode_Equal: Mean +- std dev: 7.45 ns +- 0.02 ns

Why change unicode_compare_eq()?

I like to reduce the scope of variables by only declaring them where they are first assigned.

There are no reasons to have two identical static functions with different names.

Once this PR will be merged, I plan to write a following PR to remove unicode_compare_eq() and _PyUnicode_EQ().

I limited this PR to optimizing unicode_eq() to be able to measure the speedup. Otherwise, it was too difficult to measure it.

If you plan to removeunicode_compare_eq(), do not make cosmetic changes to it.

s/unicode_compare_eq/unicode_eq/

If you plan to remove unicode_compare_eq(), do not make cosmetic changes to it.

As you wish: I reverted unicode_compare_eq() changes.

Merged, thanks for reviews.

Follow-up PR:#125114 removes _PyUnicode_EQ().