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Re: Add VIEW_CONVERT_EXPR to operand_equal_p
- From: Jan Hubicka <hubicka at ucw dot cz>
- To: Eric Botcazou <ebotcazou at adacore dot com>
- Cc: Jan Hubicka <hubicka at ucw dot cz>, gcc-patches at gcc dot gnu dot org, Richard Biener <richard dot guenther at gmail dot com>
- Date: Fri, 30 Oct 2015 16:17:59 +0100
- Subject: Re: Add VIEW_CONVERT_EXPR to operand_equal_p
- Authentication-results: sourceware.org; auth=none
- References: <20151014162944 dot GE16672 at kam dot mff dot cuni dot cz> <CAFiYyc2+HEuHcz8Mmp0PeoNvPiXVhv9-K2iRPMAG2Q7ZuFLzQg at mail dot gmail dot com> <20151029150215 dot GA34652 at kam dot mff dot cuni dot cz> <1739286 dot yXNLCe3m6q at polaris>
> > > But yes, the VIEW_CONVERT "stripping" is a bit fragile and I don't
> > > remember what exactly we gain from it (when not done on registers).
> >
> > I guess gain is really limited to Ada - there are very few cases we do VCE
> > otherwise. (I think we could do more of them). We can make
> > useless_type_conversion NOP/CONVERT only. That in fact makes quite a sense
> > because those are types with gimple operations on it. Perhaps also VCE on
> > vectors, but not VCE in general.
>
> FWIW that's fine with me. Yes, Ada tends to generate a lot of VCEs but I try
> to get rid of the useless ones as much as I can so assistance from the middle-
> end is not really required. I'll test Richard's patch and install it if the
> outcome is positive (unless you want to do the vector thing right away).
Lets go with this patch and hopefully stabilize the tree. I don't think the vector
conversions represent an important case.
Honza
>
> --
> Eric Botcazou