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Re: [PATCH, rtl-optimization]: Enhance post-reload compare elimination pass to handle arithmetic operations with implicit extensions


On Tue, Apr 24, 2012 at 6:56 PM, Uros Bizjak <ubizjak@gmail.com> wrote:

> Back to converting x86 to post-reload compare elimination pass.
>
> Arithmetic operations in x86_64 can implicitly zero extend the result,
> and set flags according to the non-extended result. Following testcase
> should exercise both features:
>
> 2012-04-24 ?Uros Bizjak ?<ubizjak@gmail.com>
>
> ? ? ? ?* compare-elim.c (try_eliminate_compare): Also handle operands with
> ? ? ? ?implicit extensions.
>
> Patch is lightly tested on x86_64-pc-linux-gnu, together with attached
> WIP patch.
>
> Opinions? Since it looks quite safe, is it OK for mainline?

The full bootstrap and regression test passed on x86_64-pc-linux-gnu
{,-m32} with attached x86 WIP patch (the updated patch disables some
interfering peephole2s). I am confident that compare-elim.c change
doesn't cause regressions, so this message is a formal request for a
patch inclusion.

BTW: This is also the first time x86 bootstrapped with enabled
post-reload compare elimination pass.

Uros.

Attachment: x86-wip.diff.txt
Description: Text document


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