TGSI was the intermediate representation (IR) developed for Mesa's Gallium3D drivers by Tungsten Graphics at the time. It worked fine more than a decade ago but since then the Mesa front-ends and hardware drivers have largely transitioned over to the superior NIR format. Work is underway toward eliminating TGSI in the Mesa codebase.

Mesa developer Erik Faye-Lund presented at this week's XDC 2026 conference on the goal of eliminating TGSI in the Mesa codebase. While TGSI usage has decreased significantly over the years as more code has transitioned to using NIR, there still is some TGSI usage such as by VMware's SVGA virtual driver, TGSI text in the protocol for the VirGL driver, the Intel i915g shader compiler, the Nouveau NV30 shader compiler, and other legacy driver usage. The D3D10UMD driver by VMware also emits TGSI on the Mesa front-end side.

Erik is working toward removing TGSI from the Gallium3D interface, converting remaining shaders to NIR, and converting other code toward NIR or in other cases potentially removing the code from Mesa.

It's going to be a lengthy process, but eventually TGSI may finally be sunset within Mesa.