From: Segher Boessenkool <segher@kernel.crashing.org>
To: Jeff Law <law@redhat.com>
Cc: gcc-patches@gcc.gnu.org, bschmidt@redhat.com
Subject: Re: [PATCH 3/9] dce: Don't dead-code delete separately wrapped restores
Date: Fri, 09 Sep 2016 15:59:00 -0000 [thread overview]
Message-ID: <20160909155124.GG28260@gate.crashing.org> (raw)
In-Reply-To: <61006d4e-2345-749b-19f6-2d342acba6b4@redhat.com>
On Thu, Sep 08, 2016 at 11:50:56AM -0600, Jeff Law wrote:
> On 07/31/2016 07:42 PM, Segher Boessenkool wrote:
> >Deleting restores (before a noreturn) that are dead confuses dwarf2cfi.
> >
> >2016-06-07 Segher Boessenkool <segher@kernel.crashing.org>
> >
> > * dce.c (delete_unmarked_insns): Don't delete instructions with
> > a REG_CFA_RESTORE note.
> I don't really understand this one. Why is the restore marked dead and
> why doesn't that happen for normal epilogues? Something wonky seems to
> be going on here.
Because it's not behind a NOTE_INSN_EPILOGUE_BEGIN it is not treated
specially by DCE, like insns in "normal" epilogues are.
It is marked dead because it *is* dead: the value in the callee-save
register is not used by anything anymore (noreturn!)
Segher
next prev parent reply other threads:[~2016-09-09 15:51 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-01 1:43 [PATCH v2 0/9] Separate shrink-wrapping Segher Boessenkool
2016-08-01 1:43 ` [PATCH 3/9] dce: Don't dead-code delete separately wrapped restores Segher Boessenkool
2016-09-08 17:52 ` Jeff Law
2016-09-09 15:59 ` Segher Boessenkool [this message]
2016-09-09 16:39 ` Jeff Law
2016-08-01 1:43 ` [PATCH 2/9] cfgcleanup: Don't confuse CFI when -fshrink-wrap-separate Segher Boessenkool
2016-09-08 17:51 ` Jeff Law
2016-08-01 1:43 ` [PATCH 1/9] separate shrink-wrap: New command-line flag, status flag, hooks, and doc Segher Boessenkool
2016-08-29 9:31 ` Bernd Schmidt
2016-08-29 14:30 ` Segher Boessenkool
2016-09-08 17:37 ` Jeff Law
2016-09-09 11:03 ` Bernd Schmidt
2016-09-09 15:13 ` Segher Boessenkool
2016-09-09 18:31 ` Jeff Law
2016-09-09 20:41 ` Segher Boessenkool
2016-09-12 16:49 ` Jeff Law
2016-09-09 15:51 ` Jeff Law
2016-09-09 15:40 ` Segher Boessenkool
2016-09-09 16:58 ` Jeff Law
2016-09-08 17:48 ` Jeff Law
2016-09-09 15:44 ` Segher Boessenkool
2016-08-01 1:57 ` [PATCH 9/9] rs6000: Separate shrink-wrapping Segher Boessenkool
2016-08-01 1:57 ` [PATCH 8/9] shrink-wrap: shrink-wrapping for separate components Segher Boessenkool
2016-09-08 19:03 ` Jeff Law
2016-09-09 22:03 ` Segher Boessenkool
2016-09-12 18:21 ` Jeff Law
2016-09-14 13:45 ` Segher Boessenkool
2016-09-15 16:47 ` Jeff Law
2016-08-01 1:57 ` [PATCH 4/9] regrename: Don't rename restores Segher Boessenkool
2016-09-08 17:54 ` Jeff Law
2016-09-09 21:05 ` Segher Boessenkool
2016-09-12 17:01 ` Jeff Law
2016-08-01 1:57 ` [PATCH 7/9] cprop: Leave RTX_FRAME_RELATED_P instructions alone Segher Boessenkool
2016-09-08 18:34 ` Jeff Law
2016-09-09 21:21 ` Segher Boessenkool
2016-08-01 2:12 ` [PATCH 5/9] regrename: Don't run if function was separately shrink-wrapped Segher Boessenkool
2016-09-08 17:54 ` Jeff Law
2016-08-01 2:12 ` [PATCH 6/9] sel-sched: Don't mess with register restores Segher Boessenkool
2016-08-04 7:33 ` Andrey Belevantsev
2016-09-08 17:55 ` Jeff Law
2016-09-09 21:13 ` Segher Boessenkool
2016-09-12 17:39 ` Jeff Law
2016-09-14 13:28 ` Segher Boessenkool
2016-08-04 0:05 ` [PATCH v2 0/9] Separate shrink-wrapping Segher Boessenkool
2016-08-24 16:04 ` Segher Boessenkool
2016-08-26 13:03 ` Bernd Schmidt
2016-08-26 13:48 ` David Malcolm
2016-08-26 13:55 ` Bernd Schmidt
2016-08-26 14:50 ` Segher Boessenkool
2016-08-26 15:03 ` Bernd Schmidt
2016-08-26 16:27 ` Segher Boessenkool
2016-09-08 16:58 ` Jeff Law
2016-09-09 15:26 ` Segher Boessenkool
2016-09-09 16:26 ` Jeff Law
2016-09-09 16:51 ` Segher Boessenkool
2016-09-09 17:22 ` Jeff Law
2016-08-30 12:31 ` Michael Matz
2016-09-08 16:41 ` Jeff Law
2016-09-09 6:31 ` Segher Boessenkool
2016-09-09 15:28 ` Jeff Law
2016-09-09 15:43 ` Segher Boessenkool
2016-09-09 18:25 ` Jeff Law
2016-09-09 20:29 ` Segher Boessenkool
2016-09-08 17:20 ` Jeff Law
2016-09-09 15:33 ` Segher Boessenkool
2016-09-09 16:49 ` Jeff Law
2016-09-09 17:00 ` Segher Boessenkool
2016-09-09 17:44 ` Jeff Law
2016-09-09 19:36 ` Jeff Law
2016-09-09 21:00 ` Segher Boessenkool
2016-09-12 11:00 ` Bernd Schmidt
2016-09-12 16:59 ` Jeff Law
2016-09-14 13:22 ` Segher Boessenkool
-- strict thread matches above, loose matches on Subject: below --
2016-06-08 1:48 [PATCH 0/9] separate shrink-wrapping Segher Boessenkool
2016-06-08 1:48 ` [PATCH 3/9] dce: Don't dead-code delete separately wrapped restores Segher Boessenkool
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