On 16/11/20 15:25 -0500, Patrick Palka via Libstdc++ wrote:
My ranges transcription of the std::search_n implementation for random
access iterators missed a crucial part of the algorithm which the tests
unfortunately didn't catch. When __remainder is less than __count at
the start of an iteration of the outer while loop, it means we're
continuing a run of __count - __remainder identical elements from the
previous iteration in which the backwards scan got interrupted by the
predicate failing. If the backwards scan gets interrupted again at this
next iteration, we need to reset __remainder so that it's offset only by
the size the most recent run of identical elements, rather than by the
sum of all the (disjoint) runs.
This patch fixes this appropriately, mirroring how it's done in the
corresponding std::search_n implementation.
Tested on x86_64-pc-linux-gnu, does this look OK for trunk and the 10
branch?
OK, thanks.
