GLSL IR To TGSI Translator Ready To Be Merged Into Mesa

[Plombo]

It would be good to take a few random shaders those games use and compare the TGSI generated by both. I remember originally you said the new code was not quite as good as the old, but close. Has that been completely fixed, or is it possible some shaders could have regressed?

It is possible that some shaders could have regressed, but I have yet to find one. When I said that the new code was not as good as the old, I was mostly referring to copy propagation from temporary to output registers. But most of the drivers will optimize that out anyway after converting to their own IR. (I know nv50, nvc0, and llvmpipe do, and presumably r300g as well.) For everything I've benchmarked on my NVA5 card using the nv50 driver, there has been no measurable difference in framerate between glsl_to_tgsi and ir_to_mesa+mesa_to_tgsi.

Also, do you know if there has been any improvement in the compile time of shaders? I'm guessing that's all spent inside the actual GLSL compiler and not the translation code.

I haven't measured it, but I don't think there is any difference. I know that there is about the same delay while compiling shaders when I play Portal under Wine.

[Prescience500]

Isn't the GLSL IR to TGSI traslator one of the things that is blocking Intel from switching to Gallium3d? Also, is it possible to eventually use GLSL directly without translating it?

[marek]

Isn't the GLSL IR to TGSI traslator one of the things that is blocking Intel from switching to Gallium3d?

I don't think so. They apparently don't want to throw away the codebase of their classic driver.

Also, is it possible to eventually use GLSL directly without translating it?

Maybe. There seems to be an increased interest for Gallium to go in that direction.