Intel Adds Mesa IR To NIR Translator & Makes Other NIR Improvements
Written by Michael Larabel in Mesa on 28 March 2015 at 08:43 AM EDT. Add A Comment
The NIR intermediate representation for Mesa continues taking flight and driven by Intel's open-source developers.

NIR is the new IR for Mesa that's much better than GLSL IR and was designed by a young, promising programmer. Intel developers have been particularly interested in using NIR for optimizing their driver while Gallium3D drivers like the Raspberry Pi VC4 component have too been interested in using NIR.

Kenneth Graunke of Intel has committed a Mesa IR to NIR translator, which is derived from Eric Anholt's TGSI to NIR translator for Gallium3D's representation. This Mesa IR to NIR pass is just over one thousand lines of code.

Ken also enabled NIR for ARB_vertex_program support to generate SIMD8 VS programs rather than SIMD4x2.

Ken also landed ARB_fragment_program support within Intel's NIR back-end. When NIR Is enabled with this new code, the number of total instructions in their shared programs they test is down by 11%! All the details can be found in the aforelinked Git commit.

There's also been various other Mesa NIR improvements this week too. Intel driver users wanting to test out NIR can set the INTEL_USE_NIR environment variable to true, assuming you're riding on Mesa Git code.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter or contacted via

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