From: Martin Jambor <mjambor@suse.cz>
To: Feng Xue OS <fxue@os.amperecomputing.com>,
"gcc-patches\@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
Jan Hubicka <hubicka@ucw.cz>
Subject: Re: [PATCH] Setup predicate for switch default case in IPA (PR ipa/91089)
Date: Thu, 29 Aug 2019 15:14:00 -0000 [thread overview]
Message-ID: <ri6imqgaufd.fsf@suse.cz> (raw)
In-Reply-To: <BYAPR01MB48690FF0F2D7FCFE48DC17B7F7F20@BYAPR01MB4869.prod.exchangelabs.com>
Hi,
On Fri, Jul 12 2019, Feng Xue OS wrote:
> IPA does not construct executability predicate for default case of switch statement.
> So execution cost of default case is not properly evaluated in IPA-cp, this might
> prevent function clone for function containing switch statement, if certain non-default
> case is proved to be executed after constant propagation.
>
> This patch is composed to deduce predicate for default case, if it turns out to be a
> relative simple one, for example, we can try to merge case range, and use
> comparison upon range bounds, and also range analysis information to simplify
> predicate.
>
I have read through the patch and it looks OK to me but I cannot approve
it, you have to ping Honza for that. Since you decided to use the value
range info, it would be nice if you could also add a testcase where it
plays a role. Also, please don't post changelog entries as a part of
the patch, it basically guarantees it will not apply for anybody, not
even for you when you update your trunk.
Thanks for working on this,
Martin
> Feng
>
> ----
> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
> index 3d92250b520..4de2f568990 100644
> --- a/gcc/ChangeLog
> +++ b/gcc/ChangeLog
> @@ -1,3 +1,10 @@
> +2019-07-12 Feng Xue <fxue@os.amperecomputing.com>
> +
> + PR ipa/91089
> + * ipa-fnsummary.c (set_switch_stmt_execution_predicate): Add predicate
> + for switch default case using range analysis information.
> + * params.def (PARAM_IPA_MAX_SWITCH_PREDICATE_BOUNDS): New.
> +
> 2019-07-11 Sunil K Pandey <sunil.k.pandey@intel.com>
>
next prev parent reply other threads:[~2019-08-29 15:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 8:51 Feng Xue OS
2019-08-29 15:14 ` Martin Jambor [this message]
2019-08-30 8:32 ` Feng Xue OS
2019-09-02 3:06 ` [PATCH V2] " Feng Xue OS
2019-09-14 15:57 ` Jan Hubicka
2019-09-16 10:11 ` [PATCH 1/2 V3] " Feng Xue OS
2019-09-16 15:04 ` Jan Hubicka
2019-09-17 13:51 ` Feng Xue OS
2019-09-16 10:16 ` [PATCH 2/2 V3] Use post-dom info to update if/switch predicate " Feng Xue OS
2019-09-16 15:05 ` Jan Hubicka
2019-09-17 13:54 ` Feng Xue OS
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