------- Comment #17 from maxim at codesourcery dot com 2007-10-28 20:04 ------- Subject: Re: [4.3 Regression] slow compilation on ia64 (postreload scheduling)
jakub at gcc dot gnu dot org wrote: > ------- Comment #15 from jakub at gcc dot gnu dot org 2007-10-28 19:10 > ------- > Compared to 20070803 with -O3 -fno-tree-vectorize there are now 100 times more > calls to rtx_needs_barrier and 44 times more calls to > safe_group_barrier_needed. > E.g. the latter is horribly expensive, e.g. copying around 401 * sizeof > (struct > reg_write_state) == 1604 bytes several times. The underlying problem is that list of ready to schedule instructions now became larger than it was before and the scheduler tends to slow down with the size of the list growing. There already is a workaround for this problem (limiting ready list in case it is too large; see PARAM_MAX_SCHED_READY_INSNS) but it doesn't seem to do best in this case. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33922
