Experimental Patches Add NIR As Alternate IR To Gallium3D

[phoronix]

Phoronix: Experimental Patches Add NIR As Alternate IR To Gallium3D

Rob Clark has published a set of eight patches for review that add support for NIR as an alternate intermediate representation (IR) under Gallium3D...

http://www.phoronix.com/scan.php?page=news_item&px=Gallium3D-NIR-Patches

[uid313]

Isn't NIR, Gallium IR, and LLVM IR all dead now with SPIR-V?

[geearf]

Isn't NIR, Gallium IR, and LLVM IR all dead now with SPIR-V?

No.
SPIR-V will be the input IR to the graphic stack when using Vulkan, but I don't believe it will be used internally.

[zanny]

Releasing a spec for an IR is cheap. Implementing support across the ecosystem is not.

Also, SPIR is not operating at the same level as TGSI. TGSI is internal to Gallium - SPIR is more like GLSL IR except that it is standardized so that vendors stop duplicating the work of compiling shaders.

NIR and TGSI are never an exposed external format to compile against. They are generated internally so one compiler can translate from many languages (GL, DX, CL, SPIRV, etc) to many drivers. Nir is just a heavily optimized format that Intel finds makes their driver compiler run faster, that is probably applicable elsewhere, but it will be nice to see results from this patchset in testing. SPIRV is an IR for the developers of graphics programs to compile their software to, so that any supporting driver can run the IR binary as a GPU program.

[smitty3268]

Isn't NIR, Gallium IR, and LLVM IR all dead now with SPIR-V?

Nope.

[artivision]

Releasing a spec for an IR is cheap. Implementing support across the ecosystem is not.

Also, SPIR is not operating at the same level as TGSI. TGSI is internal to Gallium - SPIR is more like GLSL IR except that it is standardized so that vendors stop duplicating the work of compiling shaders.

NIR and TGSI are never an exposed external format to compile against. They are generated internally so one compiler can translate from many languages (GL, DX, CL, SPIRV, etc) to many drivers. Nir is just a heavily optimized format that Intel finds makes their driver compiler run faster, that is probably applicable elsewhere, but it will be nice to see results from this patchset in testing. SPIRV is an IR for the developers of graphics programs to compile their software to, so that any supporting driver can run the IR binary as a GPU program.

SPIR-V is an internal+ IR mostly like TGSI. No comparison with GLSL_asm and HLSL_asm. Not possible for SPIR-V to compile to TGSI, will probably replace it. The strongest possibility is SPIR->LLVM->HW or SPIR->HW.

[Drago]

SPIR-V is an internal+ IR mostly like TGSI. No comparison with GLSL_asm and HLSL_asm. Not possible for SPIR-V to compile to TGSI, will probably replace it. The strongest possibility is SPIR->LLVM->HW or SPIR->HW.

SPIR-V is on-disk format. I.e. store shaders in compiled form on the disk, and skip the first compilation stage. SPIR-V can't be optimized, or processed in some other way upfront, so other IR is needed for in-memory use like NIR or TGSI.

[libv]

If you look at the SPIR-V spec, you will notice that the original author of NIR (connor abbott) is one of the authors of the SPIR-V spec.

[smitty3268]

SPIR-V is an internal+ IR mostly like TGSI.

Nope.

No comparison with GLSL_asm and HLSL_asm.

Nope.

Not possible for SPIR-V to compile to TGSI, will probably replace it.

Nope.

The strongest possibility is SPIR->LLVM->HW

Nop... Wait, yes, you got one right, at least for radeonsi.

or SPIR->HW.

Nope. It will be SPIRV->NIR->HW, or possibly SPIRV->NIR->TGSI->HW for some drivers.

[artivision]

Nope.

Nope.

Nope.

Nop... Wait, yes, you got one right, at least for radeonsi.

Nope. It will be SPIRV->NIR->HW, or possibly SPIRV->NIR->TGSI->HW for some drivers.

TGSI to LLVM is compilation, the same for TGSI to HW and LLVM to HW. SPIRV to TGSI is a conversion of typos like HLSL to GLSL, not impossible to convert but compile is impossible. Read first.