https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121912
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #0) > Even if haystack is not random access but is bidirectional, we can _still_ > optimize the algo. Every time we match an element from the needle we can > decrement a copy of haystack_end and on the next iteration use that > decremented iterator as the end for the next loop's find_if(haystack, end, > *needle). N.B. For ranges::search we can't do this one unless we have a common range, because we can't decrement a sentinel.
