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Re: Add VIEW_CONVERT_EXPR to operand_equal_p
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: Jan Hubicka <hubicka at ucw dot cz>
- Cc: gcc-patches at gcc dot gnu dot org, Richard Biener <richard dot guenther at gmail dot com>
- Date: Fri, 30 Oct 2015 10:40:47 +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>
> > 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).
--
Eric Botcazou