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Re: ARM/getting rid of superfluous zero extension
- From: David Edelsohn <dje dot gcc at gmail dot com>
- To: Eric Botcazou <ebotcazou at adacore dot com>, Kenneth Zadeck <zadeck at naturalbridge dot com>, Christophe Lyon <christophe dot lyon at linaro dot org>
- Cc: GCC Development <gcc at gcc dot gnu dot org>
- Date: Thu, 4 Oct 2012 18:16:10 -0400
- Subject: Re: ARM/getting rid of superfluous zero extension
- References: <CAKdteOYsatVOOK3K9kSgnghgbhH1Hzyw8rc6B+7=Yr4Z3Y8h+Q@mail.gmail.com> <2058751.NnuqqeFixq@polaris>
On Thu, Oct 4, 2012 at 2:18 PM, Eric Botcazou <ebotcazou@adacore.com> wrote:
>> Any suggestion about how I could avoid generating this zero_extension?
>
> Redundant extensions have been a hot topic for some time. The combiner should
> catch the local easy cases, we have ree.c for the nonlocal easy cases and Tom
> recently posted:
> http://gcc.gnu.org/ml/gcc-patches/2012-07/msg00408.html
> which should catch more complex cases.
>
> I guess someone should gather the various missed optimization cases, draw a
> global picture of the situation and see how the various approaches could be
> fitted together.
Kenny already did that as part of the thread with Tom. Tom's patch
also is incomplete.
- David