public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "eraman at google dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/44194] struct returned by value generates useless stores Date: Thu, 16 Jun 2011 17:16:00 -0000 [thread overview] Message-ID: <bug-44194-4-vAw7e7MMWZ@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-44194-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44194 --- Comment #27 from Easwaran Raman <eraman at google dot com> 2011-06-16 17:14:38 UTC --- (In reply to comment #26) > On Wed, 15 Jun 2011, xinliangli at gmail dot com wrote: > > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44194 > > > > davidxl <xinliangli at gmail dot com> changed: > > > > What |Removed |Added > > ---------------------------------------------------------------------------- > > CC| |xinliangli at gmail dot com > > > > --- Comment #23 from davidxl <xinliangli at gmail dot com> 2011-06-15 23:14:50 UTC --- > > (In reply to comment #22) > > > > The DSE patch still leaves 2 redundant stores. > > > > > > OK, I missed this, reopening... > > > > > > > The following patch will enable DSE to remove those two stores. Does this > > > > look ok? > > > > > > Calling into the gimplifier from the RTL expander doesn't look appropriate. > > It also should use create_tmp_var, not create_tmp_reg. But I wonder why > memory allocated via assign_temp isn't marked in a way to let dse > do its job (I guess dse thinks that memory escapes?). If the mem rtx doesn't have a tree_expression associated with it, DSE assumes the memory escapes. > > > > More fundamentally, it's a little unfortunate to spill to memory a value > > > returned in registers. Can we try to use emit_group_move_into_temps here > > > instead (under the appropriate circumstances)? > > > > It would be nice if the expander does not spill the return into memory in the > > first place if possible. On other hand tagging compiler created memory > > location with temp decls so that aliaser has the symbolic information seems a > > useful mechanism. > > Sure - but I wonder why assign_temp doesn't do something equivalent > that doesn't require a automatic VAR_DECL to be created. > > Where does the aliaser catch things with the VAR_DECL around that > it doesn't without it? Is it just that when I create a VAR_DECL, TREE_ADDRESSABLE is false and may_be_aliased returns true? > Richard.
next prev parent reply other threads:[~2011-06-16 17:16 UTC|newest] Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-44194-4@http.gcc.gnu.org/bugzilla/> 2011-02-24 5:10 ` jhaberman at gmail dot com 2011-04-12 22:39 ` eraman at google dot com 2011-04-14 18:59 ` eraman at google dot com 2011-04-14 22:22 ` ebotcazou at gcc dot gnu.org 2011-04-15 9:10 ` rguenth at gcc dot gnu.org 2011-04-15 19:19 ` eraman at google dot com 2011-04-15 19:34 ` rguenther at suse dot de 2011-04-15 22:27 ` eraman at google dot com 2011-04-17 10:47 ` rguenther at suse dot de 2011-04-21 0:22 ` eraman at google dot com 2011-04-21 8:37 ` rguenther at suse dot de 2011-06-14 22:59 ` eraman at gcc dot gnu.org 2011-06-15 16:50 ` ebotcazou at gcc dot gnu.org 2011-06-15 20:35 ` eraman at google dot com 2011-06-15 21:11 ` ebotcazou at gcc dot gnu.org 2011-06-15 23:17 ` xinliangli at gmail dot com 2011-06-16 5:27 ` ebotcazou at gcc dot gnu.org 2011-06-16 7:43 ` xinliangli at gmail dot com 2011-06-16 8:37 ` rguenther at suse dot de 2011-06-16 17:16 ` eraman at google dot com [this message] 2011-06-17 8:22 ` rguenther at suse dot de 2011-06-18 9:06 ` xinliangli at gmail dot com 2011-06-18 9:29 ` ebotcazou at gcc dot gnu.org 2011-06-18 16:34 ` xinliangli at gmail dot com 2011-06-20 9:22 ` rguenther at suse dot de 2011-06-20 15:28 ` ebotcazou at gcc dot gnu.org 2011-06-20 16:27 ` xinliangli at gmail dot com 2011-06-20 16:52 ` eraman at google dot com 2011-06-22 7:58 ` ebotcazou at gcc dot gnu.org 2011-07-07 14:58 ` ebotcazou at gcc dot gnu.org 2011-12-05 17:49 ` ebotcazou at gcc dot gnu.org 2012-03-22 9:10 ` rguenth at gcc dot gnu.org 2012-03-22 17:13 ` ubizjak at gmail dot com 2012-03-22 18:35 ` ebotcazou at gcc dot gnu.org 2012-07-02 14:04 ` rguenth at gcc dot gnu.org 2012-08-06 1:23 ` chip at pobox dot com 2012-09-12 22:31 ` ebotcazou at gcc dot gnu.org 2012-09-12 23:22 ` chip at pobox dot com 2012-09-13 0:00 ` ebotcazou at gcc dot gnu.org 2012-09-14 13:30 ` ebotcazou at gcc dot gnu.org 2012-09-14 13:38 ` ebotcazou at gcc dot gnu.org 2012-09-14 17:24 ` chip at pobox dot com 2012-10-21 12:36 ` ebotcazou at gcc dot gnu.org 2012-11-02 0:29 ` eraman at gcc dot gnu.org 2010-05-19 5:06 [Bug rtl-optimization/44194] New: " jhaberman at gmail dot com 2010-05-19 9:39 ` [Bug rtl-optimization/44194] " rguenth at gcc dot gnu dot org 2010-05-19 10:14 ` jakub at gcc dot gnu dot org 2010-05-19 10:22 ` rguenth at gcc dot gnu dot org 2010-07-10 1:38 ` jhaberman at gmail dot com 2010-07-10 1:40 ` pinskia at gcc dot gnu dot org 2010-07-10 1:42 ` pinskia at gcc dot gnu dot org 2010-07-10 1:48 ` jhaberman at gmail dot com
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-44194-4-vAw7e7MMWZ@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).