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Re: if conversion running all the time
- To: gcc at gcc dot gnu dot org
- Subject: Re: if conversion running all the time
- From: Andi Kleen <ak at suse dot de>
- Date: Sat, 30 Jun 2001 14:31:53 +0200
- References: <20010630114233.A1153@gruyere.muc.suse.de>
On Sat, Jun 30, 2001 at 11:42:33AM +0200, Andi Kleen wrote:
>
> Hi,
>
> I noticed that the two if-conversion passes run on a normal compile on
> a i386 target on gcc 3.0. My understanding is that if-conversion on i386
> can only do anything on i386 when CMOV/FCMOV are enabled (-march=686), because
> the architecture has no other conditional instructions. But it seems to run even
> without that option and eat some time (upto 5% of the runtime). Is it doing
> anything useful for older architectures? Could it be disabled for arch<686
> to make gcc a little bit faster again?
Never mind. I found noce_process_if_block() now and the assumption that if
conversion is only used for *CMOV seems to be void.
-Andi