Re: [PATCH] rtl-optimization/110587 - speedup find_hard_regno_for_1

[Richard Biener <rguenther@suse.de>]

On Tue, 25 Jul 2023, Richard Biener wrote:

> The following applies a micro-optimization to find_hard_regno_for_1,
> re-ordering the check so we can easily jump-thread by using an else.
> This reduces the time spent in this function by 15% for the testcase
> in the PR.
> 
> Bootstrap & regtest running on x86_64-unknown-linux-gnu, OK if that
> passes?

Ping.

> Thanks,
> Richard.
> 
> 	PR rtl-optimization/110587
> 	* lra-assigns.cc (find_hard_regno_for_1): Re-order checks.
> ---
>  gcc/lra-assigns.cc | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/gcc/lra-assigns.cc b/gcc/lra-assigns.cc
> index b8582dcafff..d2ebcfd5056 100644
> --- a/gcc/lra-assigns.cc
> +++ b/gcc/lra-assigns.cc
> @@ -522,14 +522,15 @@ find_hard_regno_for_1 (int regno, int *cost, int try_only_hard_regno,
>  	       r2 != NULL;
>  	       r2 = r2->start_next)
>  	    {
> -	      if (r2->regno >= lra_constraint_new_regno_start
> +	      if (live_pseudos_reg_renumber[r2->regno] < 0
> +		  && r2->regno >= lra_constraint_new_regno_start
>  		  && lra_reg_info[r2->regno].preferred_hard_regno1 >= 0
> -		  && live_pseudos_reg_renumber[r2->regno] < 0
>  		  && rclass_intersect_p[regno_allocno_class_array[r2->regno]])
>  		sparseset_set_bit (conflict_reload_and_inheritance_pseudos,
>  				   r2->regno);
> -	      if (live_pseudos_reg_renumber[r2->regno] >= 0
> -		  && rclass_intersect_p[regno_allocno_class_array[r2->regno]])
> +	      else if (live_pseudos_reg_renumber[r2->regno] >= 0
> +		       && rclass_intersect_p
> +			    [regno_allocno_class_array[r2->regno]])
>  		sparseset_set_bit (live_range_hard_reg_pseudos, r2->regno);
>  	    }
>  	}
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)