Re: [PATCH] Add debug counters to back threader.

[Jeff Law <jeffreyalaw@gmail.com>]

On 11/1/2021 3:54 AM, Aldy Hernandez wrote:
> Chasing down stage3 miscomparisons is never fun, and having no way to
> distinguish between jump threads registered by a particular
> pass, is even harder.  This patch adds debug counters for the individual
> back threading passes.  I've left the ethread pass alone, as that one is
> usually benign, but we could easily add it if needed.
>
> The fact that we can only pass one boolean argument to the passes
> infrastructure has us do all sorts of gymnastics to differentiate
> between the various back threading passes.
>
> Tested on x86-64 Linux.
>
> OK?
>
> gcc/ChangeLog:
>
> 	* dbgcnt.def: Add debug counter for back_thread[12] and
> 	back_threadfull[12].
> 	* passes.def: Pass "first" argument to each back threading pass.
> 	* tree-ssa-threadbackward.c (back_threader::back_threader): Add
> 	first argument.
> 	(back_threader::debug_counter): New.
> 	(back_threader::maybe_register_path): Call debug_counter.
OK
jeff