Remove unnecessary for loop initializer in long_lshift1()

[oda-gitso]

Here is a snippet from the definition of long_lshift1() in longobject.c:

for (i = 0; i < wordshift; i++)
    z->ob_digit[i] = 0;
accum = 0;
for (i = wordshift, j = 0; j < oldsize; i++, j++) {
    accum |= (twodigits)a->ob_digit[j] << remshift;
    z->ob_digit[i] = (digit)(accum & PyLong_MASK);
    accum >>= PyLong_SHIFT;
}

There is no need for i = wordshift in the for loop initialization (it adds to the number of instructions) and I do not think it improves readability.

I don't think this requires a news entry or an issue?

[bedevere-bot]

Most changes to Python require a NEWS entry.

Please add it using the blurb_it web app or the blurb command-line tool.

[eendebakpt]

One more optimization could be to eliminate the i variable. E.g. something like

pointer = z->ob_digit[wordshift]
for (j = 0; j < oldsize; j++) {
       accum |= (twodigits)a->ob_digit[j] << remshift;
        pointer[j] = (digit)(accum & PyLong_MASK);
        accum >>= PyLong_SHIFT;
}

[eendebakpt]

@oda-gitso Did you benchmark whether this is faster? If so, can you show the results.