Re: [PATCH] Properly honor param_max_fsm_thread_path_insns in backwards threader

[Richard Biener <rguenther@suse.de>]

On Tue, 2 Aug 2022, Aldy Hernandez wrote:

> On Tue, Aug 2, 2022 at 1:45 PM Richard Biener <rguenther@suse.de> wrote:
> >
> > On Tue, 2 Aug 2022, Aldy Hernandez wrote:
> >
> > > Unfortunately, this was before my time, so I don't know.
> > >
> > > That being said, thanks for tackling these issues that my work
> > > triggered last release.  Much appreciated.
> >
> > Ah.  But it was your r12-324-g69e5544210e3c0 that did
> >
> > -  else if (n_insns > 1)
> > +  else if (!m_speed_p && n_insns > 1)
> >
> > causing the breakage on the 12 branch.  That leads to a simpler
> > fix I guess.  Will re-test and also backport to GCC 12 if successful.
> 
> Huh.  It's been a while, but that looks like a typo.  That patch was
> supposed to be non-behavior changing.

Exactly my thinking so reverting it shouldn't be a reason for
detailed questions.  Now, the contains_hot_bb computation is,
that one was introduced by Honza in r7-6476-g0f0c2cc3a17efa
together with the comment and a testcase.

So - Honza, what was the reasoning to look at raw BB counts here
rather than for example the path entry edge count?

Richard.