------- Comment #20 from zackw at panix dot com 2006-07-13 08:25 ------- Subject: Re: poor optimization choices when iterating over a std::string (probably not c++-specific)
> > However, ch isn't just copying the loop header; it is also > > copying the *entire body of the loop*, which nothing can fix. I call > > that a clear bug. > > how do you define a loop header? I was under the impression it was just the one basic block called out in the .ch dump, e.g. ;; Loop 1 ;; header 6, latch 5 ;; depth 1, level 1, outer 0 -- basic block 6 happens to contain just the code from the syntactic loop condition. Andrew informs me that this is wrong, and that in this case the header is the entire loop, but I will come back at that with 'ch should never be duplicating the entire loop; if the header is the entire loop, it should do something more sensible, like duplicate just the first basic block or something.' -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28364
