------- Comment #41 from potswa at mac dot com 2009-10-30 19:07 ------- Created an attachment (id=18934) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18934&action=view) table of benchmarks comparing various algorithms and parameters
As the Euclidean ring division algorithm sweeps the memory range at least once per ring, you can see from this table that the present RAI implementation performs very poorly for small k greater than one. The final row, "fwd +copy", is a new proposal which adds the std::copy calls to the existing forward iterator algo. It remains compatible with bidirectional iterators and, from this data, looks pretty good. Its moderately bad showing in the final column I don't yet understand. The special cases for left and right by one should use std::move and std::move_backward, respectively, I guess. I'm not sure what state of testing I left things at before, but let's look at the performance numbers first. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41351
