https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108696
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Andrew Macleod from comment #2) > Created attachment 54437 [details] > possible patch > > This patch should successfully short circuit unnecessary checks. untested in > compiler.i > > Where did you get a 17% time in DOM? when I run compiler.i I get > dominator optimization : 38.28 ( 2%) > where most of the time is in > machine dep reorg :1447.64 ( 60%) > > I'll check this patch for correctness and to see if it generally makes any > time improvements that are measurable elsewhere. It helps the callgrind profile but doesn't show any effect on the -ftime-report or a perf profile. For the testcase the bitmap operations in ranger are definitely visible in a perf profile (with call traces), and with -O1 it's mostly DOM and jump-threading that perform any ranger ops when diagnostics are disabled. That said, not allocating the self-relation bitmaps at query time is definitely good (not 100% sure if the patch achieves that).
