Branchless programming

[yakra]

From the description of this video:

Have you ever written code like this: void f(bool b, long x, long& s) { if (b) s += x; }

My mind instantly goes to { s += b*x }. (Haha yup. And he gets to exactly that at 56:58 in the video.) Not just C++ -- I've done this kinda thing in Python too (though not committed yet) and it did seem to help a bit:

sqlfile.write("('" + r.root + "','" + t.traveler_name + "','" + str(m) + "','" + str(int(m >= r.mileage)) + "')\n")

can lose if siteupdate.py line numbers from d56e5a67555922d06730363ca779c0acdc224dac

• [ ] 342
• [ ] 1181
• [ ] con_beg & con_end?
• [ ] 2974
• [ ] 3397
• [ ] 3624, except it conflicts with r2cr @ c8237dd
• [ ] 3636
• [ ] 4189
• [ ] 4679
• [ ] ToDo: C++

+= operator

• [ ] 127
• [ ] 2437
• [ ] 3396
• [ ] ToDo: C++

|=? &=?

• [ ] nothing in Py; look in C++

---

• [ ] ternary operators (branchless? See 55:50)
• Replacing && and || with bitwise & and |, +, * etc.
  • [ ] if (lit1 == r->alt_label_hash.end() || lit2 == r->alt_label_hash.end())
  • [ ] active_or_preview
  • [ ] find more examples
• [ ] use bool as array index

[yakra]

https://www.reddit.com/r/programming/comments/mmjrez/branchless_programming_why_if_is_sloowww_and_what/

• [ ] A couple ToUpper demonstrations start just before 11 mins.

[yakra]

• [ ] li_count += li https://github.com/yakra/DataProcessing/blob/9dcf0a5549cc6100082710637e2653e99afd8c80/siteupdate/cplusplus/classes/Waypoint/Waypoint.cpp#L224