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Re: [tree-ssa] Generic NRV optimization [was Re: two-element struct performance (was: strict-aliasing and typedefs) ]
- From: law at redhat dot com
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: Andreas Schwab <schwab at suse dot de>, Joe Buck <jbuck at synopsys dot com>, Gabriel Dos Reis <gdr at integrable-solutions dot net>, Brad Lucier <lucier at math dot purdue dot edu>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 26 Feb 2004 13:24:12 -0700
- Subject: Re: [tree-ssa] Generic NRV optimization [was Re: two-element struct performance (was: strict-aliasing and typedefs) ]
- Reply-to: law at redhat dot com
In message <1077825678.16194.483.camel@localhost.localdomain>, Diego Novillo wr
ites:
>The former is what I was hinting at with the idea of moving the RTL
>expanding logic from expand_return(). It would have to be adapted, of
>course.
Yup. Worse yet, you have to look at anything which uses DECL_RTL of
the the return value and make sure it's doing the right thing.
>The latter is going to prevent NRV on any target that builds a PARALLEL
>or a REG RETURN_DECL, wouldn't it?
Yes. But in those cases the return value is going into registers anyway.
Those cases are a smaller benefit than the one we do handle (return value
in memory).
jeff