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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/94092] Code size and performance degradations after -ftree-loop-distribute-patterns was enabled at -O[2s]+ Date: Wed, 24 Feb 2021 07:43:57 +0000 [thread overview] Message-ID: <bug-94092-4-OfEriU3I7A@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-94092-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94092 --- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> --- Yes, it was expected that the patch cannot handle all cases since most definitely the ldist transform loses information on the access that is otherwise used to improve alignment info. I suggested to add __builtin_mem{set,cpy,move} variants with an extra argument specifying the (common, for cpy/move) 'alignment size'. Note that for unbound loop bounds we want to dispatch to libc memset even when we know much about alignment since libc is expected to have optimal code sequences for a variety of alignment/size combinations. As said elsewhere I believe we have code that can dynamically dispatch between a short inline sequence and a libcall dependent on the actual length but I don't remember whether this is/was in generic code or in target specific code (but I think it is done only when value-profile data is available).
next prev parent reply other threads:[~2021-02-24 7:43 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-09 6:06 [Bug tree-optimization/94092] New: " bina2374 at gmail dot com 2020-03-09 6:17 ` [Bug tree-optimization/94092] " pinskia at gcc dot gnu.org 2020-03-09 6:29 ` pinskia at gcc dot gnu.org 2020-03-09 6:30 ` pinskia at gcc dot gnu.org 2020-03-09 7:37 ` glisse at gcc dot gnu.org 2020-03-09 9:48 ` rguenth at gcc dot gnu.org 2021-02-19 8:05 ` aoliva at gcc dot gnu.org 2021-02-23 23:57 ` wilson at gcc dot gnu.org 2021-02-24 7:43 ` rguenth at gcc dot gnu.org [this message] 2021-02-24 9:05 ` bina2374 at gmail dot com 2021-02-24 9:20 ` rguenth at gcc dot gnu.org 2021-02-26 6:35 ` bina2374 at gmail dot com 2021-03-03 6:30 ` bina2374 at gmail dot com 2021-03-03 8:03 ` rguenther at suse dot de 2021-04-29 4:24 ` aoliva at gcc dot gnu.org 2021-04-30 14:38 ` law at gcc dot gnu.org 2021-05-03 6:28 ` rguenther at suse dot de 2021-05-04 12:26 ` rguenth at gcc dot gnu.org
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