On Wed, 2020-03-04 at 08:39 +0000, Yangfei (Felix) wrote:
> Hi,
>
> This is a simple fix for PR94026.
> With this fix, combine will try make an extraction if we are in a equality
> comparison and this is an AND
> with a constant which is power of two minus one. Shift here should be an
> constant. For example, combine
> will transform (compare (and (lshiftrt x 8) 6) 0) to (compare (zero_extract
> (x 2 9)) 0).
>
> Added one test case for this. Bootstrap and tested on both x86_64 and
> aarch64 Linux platform.
> Any suggestion?
>
> Thanks,
> Felix
>
> gcc:
> +2020-03-04 Felix Yang <felix.y...@huawei.com>
> +
> + PR rtl-optimization/94026
> + * combine.c (make_compound_operation_int): Make an extraction
> + if we are in a equality comparison and this is an AND with a
> + constant which is power of two minus one.
> +
>
> gcc/testsuite:
> +2020-03-04 Felix Yang <felix.y...@huawei.com>
> +
> + PR rtl-optimization/94026
> + * gcc.dg/pr94026.c: New test.
Just a note. We're in stage4 of our development cycle, meaning we focus on
regression bugfixes. I've queued this for evaluation in gcc-11.
jeff
