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Re: SMS scheduling
- From: Mostafa Hagog <MUSTAFA at il dot ibm dot com>
- To: Richard Henderson <rth at redhat dot com>
- Cc: Canqun Yang <canqun at nudt dot edu dot cn>, gcc at gcc dot gnu dot org, Ayal Zaks <ZAKS at il dot ibm dot com>
- Date: Thu, 30 Sep 2004 10:51:31 +0200
- Subject: Re: SMS scheduling
Richard Henderson <rth@redhat.com> wrote on 30/09/2004 10:42:14:
> On Thu, Sep 30, 2004 at 10:03:37AM +0200, Mostafa Hagog wrote:
> > For 4.0 SMS intra-loop memory dependencies are detected using
> > the alias.c (as in haifa-sched) for inter-loop memory dependencies
> > we are very conservative and assume that all memory accesses are
> > aliased.
>
> alias.c is flow insensative, and thus as conservative as you
> could want. Why aren't you using it all the time?
The answer is within your question; flow insensitive.
In SMS we are interested in loop-carried dependancies
and this is not provided by alias.c. One thought is to
propagate the dependency information from trees down to the
RTL (Sebastian Bob looked into this). This is a long term
working item for SMS.
Mostafa.