Implement GetGroupWaveIndex and GetGroupWaveCount

[JoeCitizen]

Implement Group Wave Index and Group Wave Count as proposed by:
https://github.com/microsoft/hlsl-specs/blob/main/proposals/0048-group-wave-index.md

Added two new intrinsics:

• GetGroupWaveIndex - returns the index of the wave in the thread group
• GetGroupWaveCount - returns the number of waves in the thread group

Limited to Shader Model 6.10 and Compute, Mesh, Node and Amp. shaders.

Added basic test.

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[damyanp]

Could you add something to ReleaseNotes.md please?

[damyanp]

Seems to LGTM, but I'm not an expert in this area.

@tex3d - do we need to wait for #7947 to land before merging this?

[tex3d]

We have several SM 6.10 features staged in PRs now. In order to reduce conflicts, I'd like to suggest we make a separate PR reserving the HLSL Intrinsics and the experimental DXIL ops ahead of the rest of the changes.

This means a PR with just the additions to gen_intrin_main.txt, hctdb.py, nullptr , generated changes (hlsl_intrinsic_opcodes.json, DxilConstants.h, DXIL.rst, DxilInstructions.h, DxilOperations.cpp), and initial EmptyLower table entries for gLowerTable in HLOperationLower.cpp.

Of course, this will also depend on getting #7947 in first.

[tex3d]

I've put a PR up for reserving these operations here: #7995.

Once that's merged, this should be rebased onto main, but you won't want some of your changes here.

You don't need the changes in the generated files, or the addition of the HLSL instrinsics in gen_intrin_main.txt or DXIL ops in hctdb.py, or the HL op reservations in hlsl_intrinsic_opcodes.json.

You'll want to take what's in main for HLOperationLower.cpp's gLowerTable, then update the lowering function to TranslateWaveToVal.

[tex3d]

I did a rebase and a test update, while catching a fault with the ordering of the lowering table entries in the opcode reservation change. Since it's not based on this branch (it's a rebase), I put the branch up here:
https://github.com/tex3d/DirectXShaderCompiler/tree/Group-Wave-Intrinsics

You can reset your branch to this and iterate from there to save a bunch of work.

[tex3d]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[s-perron]

The SPIR-V changes look good. I did not review the rest.

[tex3d]

I believe this is already covered by existing infrastructure (generated code) based on shader_stages set in hctdb.py:

DirectXShaderCompiler/utils/hct/hctdb.py

Line 1104 in 0d5dd89

i.shader_stages = ("compute", "mesh", "amplification", "library")

Note: node shaders map to "compute" in this set.

That said, we should probably have tests that verify these are accepted in the appropriate stages and validation tests verifying they are rejected in other stages.

[tex3d]

To follow-up:

• I filed issue [0048] GroupWaveIndex: Clarify Node shader behavior, especially for Thread-Launch hlsl-specs#765 regarding thread-launch node shaders, since those should be disallowed
• I think we should remove "library" from this set I linked to in hctdb.py, because it refers to non-entry functions in runtime-consumed DXIL libraries, and these are only callable by DXR shaders, where these ops are disallowed.