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From: "qinzhao at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/102276] -ftrivial-auto-var-init fails to initialize a variable, causes a spurious warning
Date: Mon, 14 Feb 2022 17:02:07 +0000	[thread overview]
Message-ID: <bug-102276-4-vgPsXdu4nM@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102276-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102276

--- Comment #8 from qinzhao at gcc dot gnu.org ---
(In reply to Jakub Jelinek from comment #7)
> If we just want to avoid the warning in cases like that (there is nothing
> wrong in the testcases themselves, the warning just warns about an
> implementation detail that a normally uninitialized variable will be really
> uninitialized even despite the -ftrivial-auto-var-init= option), then
> maybe_warn_switch_unreachable
> already has:
>       if (gimple_code (stmt) == GIMPLE_GOTO
>           && TREE_CODE (gimple_goto_dest (stmt)) == LABEL_DECL
>           && DECL_ARTIFICIAL (gimple_goto_dest (stmt)))
>         /* Don't warn for compiler-generated gotos.  These occur
>            in Duff's devices, for example.  */;
> and so for flag_auto_var_init > AUTO_INIT_UNINITIALIZED perhaps we could also
> avoid warnings on:
> 1) call to .DEFERRED_INIT
> 2) call to __builtin_clear_padding if the second argument is present and
> non-zero
> 3) I guess we would need not to warn on a gimple assign store right after
> the .DEFERRED_INIT call that has the lhs of .DEFERRED_INIT as rhs
> anything else?
Yes, I think the above 3 should include all the cases.

  parent reply	other threads:[~2022-02-14 17:02 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-10 14:17 [Bug middle-end/102276] New: " amonakov at gcc dot gnu.org
2021-09-13 10:14 ` [Bug middle-end/102276] " rguenth at gcc dot gnu.org
2021-09-13 17:50 ` amonakov at gcc dot gnu.org
2021-09-14 17:55 ` kees at outflux dot net
2022-02-12 18:14 ` kees at outflux dot net
2022-02-12 20:22 ` pinskia at gcc dot gnu.org
2022-02-14  7:26 ` rguenth at gcc dot gnu.org
2022-02-14 16:08 ` jakub at gcc dot gnu.org
2022-02-14 17:02 ` qinzhao at gcc dot gnu.org [this message]
2022-02-14 23:21 ` qinzhao at gcc dot gnu.org
2022-02-15  8:16 ` rguenther at suse dot de
2022-02-15 16:02 ` qinzhao at gcc dot gnu.org
2022-02-15 19:55 ` qinzhao at gcc dot gnu.org
2022-02-17  7:22 ` rguenther at suse dot de
2022-02-17 19:57 ` qinzhao at gcc dot gnu.org
2022-03-02 16:55 ` cvs-commit at gcc dot gnu.org
2022-03-02 16:56 ` qinzhao at gcc dot gnu.org

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