> That would require us to maintain file name list aside from path list,
> wouldn't it?

Yes, it would.

> BTW, I had a look at it again and moved the code into
> _rtld_search_library_path() so that I could save calls to
> _rtld_check_library() in many cases (with mozilla, the number is 418).

All that does is save function call overhead 418 times.  That change
is largely a noop.

What you need to save is all the calls to _rtld_search_library_path()
that miss (i.e. there is no such file in that directory, and we know
that because we searched for this file before).