Re: [PATCH/RFC take #2] cprop_hardreg... Third time's a charm.

[Jeff Law <jeffreyalaw@gmail.com>]

On 6/3/2022 11:27 AM, Roger Sayle wrote:
> Hi Richard,
> Here's a revised version of my patch incorporating both your suggestions.
> The algorithm now uses two worklist vectors, and pointers to them,
> alternating between them on each iteration, which allows the code to
> handle an arbitrary number of passes without the previous code duplication.
> This then allows a "for (pass=2; pass<=passes; pass++)"-like idiom, that allows
> it to try two passes (the current behaviour) at -O1, but three passes with
> -O2 and higher.  This also provides a convenient point, should someone
> wish to control the number of cprop_hardreg pass iterations from the
> command line (or a backend) in future.
>
> This patch has been retested on x86_64-pc-linux-gnu, both with an without
> the proposed i386 backend patch for reduced register shuffling, with
> make bootstrap and make -k check, both with/without target_board=
> unix{-m32}, with no new failures.  Is this what you had in mind?
>
> 2022-06-03  Roger Sayle  <roger@nextmovesoftware.com>
>              Richard Biener  <rguenther@suse.de>
>
> gcc/ChangeLog
>          * regcprop.cc (pass_cprop_hardreg::execute): Perform a third
>          iteration over each basic block that was updated by the second
>          iteration.
OK
jeff