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[Bug tree-optimization/23619] Missed pre opportunity
- From: "dberlin at dberlin dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 29 Aug 2005 13:40:42 -0000
- Subject: [Bug tree-optimization/23619] Missed pre opportunity
- References: <20050829090219.23619.rakdver@gcc.gnu.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From dberlin at gcc dot gnu dot org 2005-08-29 13:40 -------
Subject: Re: Missed pre opportunity
On Mon, 29 Aug 2005, pinskia at gcc dot gnu dot org wrote:
>
> ------- Additional Comments From pinskia at gcc dot gnu dot org 2005-08-29 12:53 -------
> Yes it is a dup as, the issue is we don't pre things for:
> if (a)
> d = b + c;
> else
> d = b + e;
>
> Where b is a complex expression (yes this is simplifing it).
As a general statement, this is true, but in a loop is different because
it should be partially redundant over the backedge.
I'm tentatively with zdenek that we should be PRE'ing something here.
I'll look at the actual dumps :)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23619