Re: [PATCH] numeric: canonicalize wide digit accumulation

On 10/11/26 12:16 AM, zengxx wrote:
> Hi,
>
> While looking at wide numeric aggregates, I found that the digit
> accumulation loop in accum_sum_add() did not auto-vectorize. It advances
> two indexes together:
>
> for (val_i = 0; val_i < val_ndigits; val_i++)
> {
> accum_digits[i] += (int32) val_digits[val_i];
> i++;
> }
>
> The attached patch advances the destination pointer once before the loop:
>
> accum_digits += accum->weight - val->weight;
> for (val_i = 0; val_i < val_ndigits; val_i++)
> accum_digits[val_i] += (int32) val_digits[val_i];
>
LGTM

> Performance below is from one local machine, so it is motivation rather
> than a universal claim. The machine is WSL2/Linux on an i5-14400F using
> GCC 13.3.0. Each number is the median of 11 runs after 2 warmups; base
> and feature used identical task files, settings, row counts, and
> disposable clusters.
> Please provide the test script. So as to facilitate testing on other
platforms.