> On 24 Jun 2025, at 7:43 pm, Jan Hubicka <hubi...@ucw.cz> wrote:
>
> External email: Use caution opening links or attachments
>
>
> Hi,
> this pass removes early-inlining from afdo pass since all inlining
> should now happen from early inliner. I tedted this on spec and there
> are 3 inlines happening here which are blocked at early-inline time by
> hitting large function growth limit. We probably want to bypass that
> limit, I will look into that incrementaly.
Thanks for doing this. Is the inlining difference here is due to annotation
that happens in auto-profile pass in the earlier implementation?
One unrelated question about scaling profiles. We seem to scale-up AFDO with
and_count_scale and scale down local_profile in some other cases. Should we
instead scale up AFDO profile to local_profile scale. Lot of the inlining and
other parameters seem to work well with that.
Thanks,
Kugan
>
> This should make the non-inlined function profile merging hopefully
> easier.
>
> It may still make sense to separate afdo inliner from early inliner to
> solve the non-transitivity issues which is not that hard to do with
> current code orgnaization. However this should be separate IPA pass
> rather then another part of afdo pass, since it can be coneptually
> separate.
>
> Boostrapped/regtested x86_64-linux, will commit it shortly.
>
> Honza
>
> gcc/ChangeLog:
>
> * auto-profile.cc: Update toplevel comment.
> (early_inline): Remove.
> (auto_profile): Don't do early inlining.
>
> diff --git a/gcc/auto-profile.cc b/gcc/auto-profile.cc
> index 8a1d9f878c6..3f8310e6324 100644
> --- a/gcc/auto-profile.cc
> +++ b/gcc/auto-profile.cc
> @@ -76,21 +76,30 @@ along with GCC; see the file COPYING3. If not see
> standalone symbol, or a clone of a function that is inlined into another
> function.
>
> - Phase 2: Early inline + value profile transformation.
> - Early inline uses autofdo_source_profile to find if a callsite is:
> + Phase 2: AFDO inline + value profile transformation.
> + This happens during early optimization.
> + During early inlning AFDO inliner is executed which
> + uses autofdo_source_profile to find if a callsite is:
> * inlined in the profiled binary.
> * callee body is hot in the profiling run.
> If both condition satisfies, early inline will inline the callsite
> regardless of the code growth.
> - Phase 2 is an iterative process. During each iteration, we also check
> - if an indirect callsite is promoted and inlined in the profiling run.
> - If yes, vpt will happen to force promote it and in the next iteration,
> - einline will inline the promoted callsite in the next iteration.
> +
> + Performing this early has benefit of doing early optimizations
> + before read IPA passe and getting more "context sensitivity" of
> + the profile read. Profile of inlined functions may differ
> + significantly form one inline instance to another and from the
> + offline version.
> +
> + This is controlled by -fauto-profile-inlinig and is independent
> + of -fearly-inlining.
>
> Phase 3: Annotate control flow graph.
> AutoFDO uses a separate pass to:
> * Annotate basic block count
> * Estimate branch probability
> + * Use earlier static profile to fill in the gaps
> + if AFDO profile is ambigous
>
> After the above 3 phases, all profile is readily annotated on the GCC IR.
> AutoFDO tries to reuse all FDO infrastructure as much as possible to make
> @@ -2217,18 +2226,6 @@ afdo_annotate_cfg (void)
> free_dominance_info (CDI_POST_DOMINATORS);
> }
>
> -/* Wrapper function to invoke early inliner. */
> -
> -static unsigned int
> -early_inline ()
> -{
> - compute_fn_summary (cgraph_node::get (current_function_decl), true);
> - unsigned int todo = early_inliner (cfun);
> - if (todo & TODO_update_ssa_any)
> - update_ssa (TODO_update_ssa);
> - return todo;
> -}
> -
> /* Use AutoFDO profile to annoate the control flow graph.
> Return the todo flag. */
>
> @@ -2254,15 +2251,9 @@ auto_profile (void)
>
> push_cfun (DECL_STRUCT_FUNCTION (node->decl));
>
> - unsigned int todo = early_inline ();
> autofdo::afdo_annotate_cfg ();
> compute_function_frequency ();
>
> - /* Local pure-const may imply need to fixup the cfg. */
> - todo |= execute_fixup_cfg ();
> - if (todo & TODO_cleanup_cfg)
> - cleanup_tree_cfg ();
> -
> free_dominance_info (CDI_DOMINATORS);
> free_dominance_info (CDI_POST_DOMINATORS);
> cgraph_edge::rebuild_edges ();
