Re: [PATCH v4] Generalize get_most_common_single_value to return k_th value & count

[Jeff Law <law at redhat dot com>]

On 7/17/19 1:55 AM, Martin Liška wrote:
> On 7/17/19 7:44 AM, luoxhu wrote:
>> Hi Martin,
>> Thanks for your review, v4 Changes as below:
>>  1. Use decrease bubble sort.
>> BTW, I have a question about hist->hvalue.counters[2], when will it become
>>  -1, please? Thanks.  Currently, if it is -1, the function will return false.
> Hi.
> 
> Thanks for that. I made a minor changes to your patch, please see it in attachment.
> -1 is a value that we use for invalidated histogram. That happens when you need
> to fit in more values during instrumentation than you have counters in the histogram.
> It helps to make reproducible builds of a software.
> 
> Martin
> 
> 
> most-common-value.patch
> 
> diff --git a/gcc/profile.c b/gcc/profile.c
> index 441cb8eb183..1151b491848 100644
> --- a/gcc/profile.c
> +++ b/gcc/profile.c
> @@ -743,6 +743,44 @@ compute_branch_probabilities (unsigned cfg_checksum, unsigned lineno_checksum)
>    free_aux_for_blocks ();
>  }
>  
> +/* Sort the histogram value and count for TOPN and INDIR_CALL types.  */
> +
> +static void
> +sort_hist_values (histogram_value hist)
> +{
> +  /* counters[2] equal to -1 means that all counters are invalidated.  */
> +  if (hist->hvalue.counters[2] == -1)
> +    return;
> +
> +  gcc_assert (hist->type == HIST_TYPE_TOPN_VALUES
> +	      || hist->type == HIST_TYPE_INDIR_CALL);
> +
> +  gcc_assert (hist->n_counters == GCOV_TOPN_VALUES_COUNTERS);
> +
> +  /* Hist value is organized as:
> +     [total_executions, value1, counter1, ..., value4, counter4]
> +     Use decrese bubble sort to rearrange it.  The sort starts from <value1,
s/decrese/decrease/


OK with that nit fixed.

jeff