Re: [PATCH] Add attribute hot judgement for INLINE_HINT_known_hot hint.

[Jan Hubicka <hubicka@ucw.cz>]

> Hi Honza,
> 
> This patch is to add attribute hot judgement for INLINE_HINT_known_hot hint.
> 
> We set up INLINE_HINT_known_hot hint only when we have profile feedback,
> now add function attribute judgement for it, when both caller and callee
> have __attribute__((hot)), we will also set up INLINE_HINT_known_hot hint
> for it.
> 
> With this patch applied
>                                  Ratio   Codesize
> ADL Multi-copy:    538.imagic_r  16.7%    1.6%
> SPR Multi-copy:    538.imagic_r  15%      1.7%
> ICX Multi-copy:    538.imagic_r  15.2%    1.7%
> CLX Multi-copy:    538.imagic_r  12.7%    1.7%
> Znver3 Multi-copy: 538.imagic_r  10.6%    1.5%
> 
> Bootstrap and regtest pending on x86_64-unknown-linux-gnu.
> OK for trunk?
> 
> Thanks,
> Lili.
> 
> gcc/ChangeLog
> 
>   * ipa-inline-analysis.cc (do_estimate_edge_time): Add function attribute
>   judgement for INLINE_HINT_known_hot hint.

Thank you.  Can you please also add a testcase that tests for this.
So you modify imagemagick marking attribute hot on the specific inline?
I will try to also look again at your earlier patch - I had very busy
summer and unfortunately lost track on this one.

Honza
> ---
>  gcc/ipa-inline-analysis.cc | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/gcc/ipa-inline-analysis.cc b/gcc/ipa-inline-analysis.cc
> index 1ca685d1b0e..7bd29c36590 100644
> --- a/gcc/ipa-inline-analysis.cc
> +++ b/gcc/ipa-inline-analysis.cc
> @@ -48,6 +48,7 @@ along with GCC; see the file COPYING3.  If not see
>  #include "ipa-utils.h"
>  #include "cfgexpand.h"
>  #include "gimplify.h"
> +#include "attribs.h"
>  
>  /* Cached node/edge growths.  */
>  fast_call_summary<edge_growth_cache_entry *, va_heap> *edge_growth_cache = NULL;
> @@ -249,15 +250,19 @@ do_estimate_edge_time (struct cgraph_edge *edge, sreal *ret_nonspec_time)
>        hints = estimates.hints;
>      }
>  
> -  /* When we have profile feedback, we can quite safely identify hot
> -     edges and for those we disable size limits.  Don't do that when
> -     probability that caller will call the callee is low however, since it
> +  /* When we have profile feedback or function attribute, we can quite safely
> +     identify hot edges and for those we disable size limits.  Don't do that
> +     when probability that caller will call the callee is low however, since it
>       may hurt optimization of the caller's hot path.  */
> -  if (edge->count.ipa ().initialized_p () && edge->maybe_hot_p ()
> +  if ((edge->count.ipa ().initialized_p () && edge->maybe_hot_p ()
>        && (edge->count.ipa () * 2
>  	  > (edge->caller->inlined_to
>  	     ? edge->caller->inlined_to->count.ipa ()
>  	     : edge->caller->count.ipa ())))
> +      || (lookup_attribute ("hot", DECL_ATTRIBUTES (edge->caller->decl))
> +	  != NULL
> +	 && lookup_attribute ("hot", DECL_ATTRIBUTES (edge->callee->decl))
> +	  != NULL))
>      hints |= INLINE_HINT_known_hot;
>  
>    gcc_checking_assert (size >= 0);
> -- 
> 2.17.1
>