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Re: GCSE store motion
- From: law at redhat dot com
- To: Daniel Berlin <dberlin at dberlin dot org>
- Cc: Roger Sayle <roger at eyesopen dot com>, gcc at gcc dot gnu dot org, Mark Mitchell <mark at codesourcery dot com>, "David S. Miller" <davem at redhat dot com>, Andreas Jaeger <aj at suse dot de>, Richard Henderson <rth at redhat dot com>
- Date: Wed, 15 May 2002 12:37:09 -0600
- Subject: Re: GCSE store motion
- Reply-to: law at redhat dot com
In message <Pine.LNX.4.44.0205151154080.24022-100000@dberlin.org>, Daniel Berlin writes:
> I "claimed" it wasn't doing anything because SPEC95/2000 runs show it
> making no improvement whatsoever.
>
> In addition, never, in any RTL dumps of any code, ever, have I seen it
> remove a single store.
>
> Nobody has claimed that it is generally useful in it's current state. In
> fact, the person who submitted it has claimed otherwise.
> It was written to address a specific case, which i've no doubt it does.
> This case rarely, if ever, occurs.
> If you want to claim it is a functional optimization that has useful
> application, please provide benchmarks that show store motion making any
> difference.
If I legally could give you the code to prove this stuff was useful to
the customer paying for it, then I would. Unfortunately that code is
highly proprietary.
You might consider looking at EEMBC which has certain gross similarities
to the code from our customer. THough I haven't looked closely enough
at EEMBC to determine if the similarities are enough to trigger the
optimization.
jeff