JIT on non-AVX PC?

[idontyboi]

Hello, I have noticed that native code generation is now enabled by default. I have opted a module in, but I observed no speedup.
I have also tried the --codegen parameter to enable it to all scripts, the CLI strangely refused stating that my configuration isn't supported.

I am on desktop, and it should work considering LuaJIT is blazing fast, sometimes beating C on this same configuration.
The desktop in question is a dozen years old. I looked under the source code of Luau JIT, only to find out that my desktop got left out.
Will the JIT eventually be supported on non-AVX CPUs?

[zeux]

We have no plans to support native code generation for pre-AVX CPUs.

[idontyboi]

That's unfortunate. Looked around the native code generation, it very heavily utilizes the non-destructive AVX-only editions of SSE instructions. I'd assume that providing a fallback for pre-AVX CPUs requires an entirely new target of native code generation, as there's far too much code relying on AVX in order to make conditionals.

Final question: When the native code generation gets the go-ahead from Roblox engineers and enabled on everything imaginable, will Roblox Studio, or even worse, the Player, attempt to use the unsupported native code generation and immediately crash on startup? I hope neither.

The PC said in question has these full specifications. The CPU doesn't even have SSE4.1, so I'd imagine it would crash anyway on a math.floor operation even if a non-AVX JIT were to be possible.

CPU: Pentium Dual-Core E6500 (SSE2, SSE3, SSSE3, 2 cores, 2 threads)
RAM: 2.00 GB of RAM Studio doesn't like this, but I can still work on simple baseplates with deleting a bunch of built-in plugins, so...
iGPU: Intel G41 Express Chipset (DirectX 10.0, OpenGL 2.1)
OS: Windows 7 x64
Storage: A spinning 7200RPM hard drive, 300GB

[zeux]

attempt to use the unsupported native code generation and immediately crash on startup

Not sure what you mean by crash on startup :) Code generation is automatically disabled when the system is not supported. The CLI currently just exits early in this case, but we could change this to a warning.

[idontyboi]

Not sure what you mean by crash on startup :)

What I mean by crash on startup, I ment attempting to execute natively generated code even under on a unsupported system. Good to know that this won't be the case under both, and that it will run inside the intrepeter. Thanks for helping out!

Speaking of the CLI (luau.exe), the CLI could have a "--codegen=force" option to force the native code generation under unsupported systems, albeit it almost certainly would crash. Operations that don't involve floating-point numbers probrably wouldn't crash.