[issue39150] See if PyToken_OneChar would be faster as a lookup table

[Andy Lester]

Andy Lester <andy at petdance.com> added the comment:

Re: branch prediction.

The branch

    if (c1>=37 && c1<=126)

could just as easily be

    if (c1>=0 && c1<=126)

with no other changes to the code.  It could be just

    if (c1<=126)

if c1 wasn't signed.

As far as branch prediction, we could make it something like

    if (c1>=0 && c1<=255)

and expand the table lookup, depending on what the likely inputs are.  I could play around with that some if anyone was interested.

I'm not trying to push on this.  Just sharing some thoughts and research.

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<https://bugs.python.org/issue39150>
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