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Re: "-fno-unswitch-loops" option have no effect?
- From: Richard Guenther <richard dot guenther at gmail dot com>
- To: ami_stuff <ami_stuff at o2 dot pl>
- Cc: gcc at gcc dot gnu dot org
- Date: Mon, 17 Aug 2009 13:38:35 +0200
- Subject: Re: "-fno-unswitch-loops" option have no effect?
- References: <5dd91bc1.7ff0289a.4a88a6a0.1e15f@o2.pl>
On Mon, Aug 17, 2009 at 2:38 AM, ami_stuff<ami_stuff@o2.pl> wrote:
> Hi,
>
> I found out that when I use "-fno-unswitch-loops" option, it have no effect - loops are unswitched anyway:
>
> -O3 -fno-unswitch-loops
>
> Because of that to avoid -funswitch-loops optimization I must use something like this:
>
> -O2 -finline-functions -fpredictive-commoning -fgcse-after-reload -ftree-vectorize
>
> Is that a bug?
Works fine for me. gcc.dg/tree-ssa/loop-6.c is unswitched with -O3
but not with -O3 -fno-unswitch-loops.
You have to be more specific. Maybe PRE or if-conversion perform
the "unswichting" for you.
Richard.
> Tested with GCC 4.4.1 (m68k).
>
> Regards
>
>