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Re: IVs optimization issue
- From: Aurelien Buhrig <aurelien dot buhrig dot gcc at gmail dot com>
- To: Richard Guenther <richard dot guenther at gmail dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Wed, 29 Feb 2012 16:08:43 +0100
- Subject: Re: IVs optimization issue
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> The issue is most probably that on GIMPLE we only deal with ptr_mode,
> not Pmode, and IVOPTs thinks that pointer induction variables will
> have ptr_mode. To fix this the cost computation would need to take
> into account ptr_mode to Pmode conversions _and_ would need to
> consider Pmode IVs in the first place (I'm not sure that will be easy).
Thank you Richard for you reply.
I guess such an issue is not in the top priority tasks of main
developers. So I think I'll have to look at it myself if I feel
confident enough to carry out such a job (I've never worked at tree level).
My main wonder is about Pmode IVs: since GIMPLE representation only
deals with ptr_mode, what differentiates a Pmode IV from a ptr_mode one?
BTW, this wonder is not limited to IVs. What does control the choice of
Pmode vs ptr_mode when mapping to RTL?
Thanks,
Aurélien