[mikemike]

Uh? This *is* the LuaJIT register allocator. Period.

Code published 2009. Description published here: https://lua-users.org/lists/lua-l/2009-11/msg00089.html (ignore the TLS cert error).

Coming up with a silly markting name, writing a naive implementation and then claiming it's their invention is impertinent. Especially since they mention LuaJIT itself in the text ...

[mkeeter]

Hi Mike,

I promise that this was a genuine case of parallel evolution – I didn't read any LuaJIT source or documentation while writing the code or article.

Afterwards, I searched for "reverse linear scan register allocation", discovered the blog post which referenced LuaJIT, and linked it in the text.

I've updated the article to move the LuaJIT reference to the top, and adjusted the phrasing to be clear that this is not an invention, it's simply an interesting implementation. What you call "naive", others may consider didactic :)

Let me know if you have other feedback or suggested changes, either here or via email (in my profile).

[mikemike]

You may want to clarify that in the GitHub repo, too. See my issue there.

If you want to go the didactic route, then consider documenting the improvements over the naive implementation: register hinting, register priorities (PHI), two-headed register picking, fixed register picking, optimized register picking for 2-operand instructions (x86/x64), register pair picking, ABI calling-conventions, weak allocations, cost heuristics, eviction heuristics, lazy/eager spill/restore, rematerialization, register shuffling (PHI) with cycle breaking, register renaming, etc. That's all in ~2000 lines of lj_asm.c.

[mkeeter]

Done, I've added the same disclaimer to the Github repo.

Given that your Github issue [1] was originally titled "Take Down Notice", I'm now hesitant to read any LuaJIT code.

If I read lj_asm.c and learn from it, will you try to take down any register allocation code that I write in the future?

[1] https://github.com/mkeeter/ssra/issues/1

[mikemike]

I had already changed the title after your reply. The objection is about the naming, which implies an invention claim without further explanation. It's not about the code.

[fros1y]

Wait,

Are you demanding that independent implementations of an idea you explicitly dedicated to the public domain must then describe the various ways your version is “superior”?

Who hurt you?

[rrss]

This is such an amazingly uncharitable response.

> I cannot possibly know all of the literature

Maybe this applies to other people too?