microsoft / microsoft/DirectXShaderCompiler

[SPIR-V] Dynamic resources use phi node of resource pointer without specifying capability

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bug needs-triage spirv
Dominant language
C++
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Merged PRs (30d)
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Description

https://godbolt.org/z/T6qzdPW93

We can see that a phi node is generated between pointers to the resource to access.

Possible solutions would be to add the noted capability as the spir-v validator requires, however this differs to how it is handled in dxil where the index to the global resource should be propagated through control flow instead of the resource.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the Godbolt reproducer at https://godbolt.org/z/T6qzdPW93 and inspect the generated SPIR-V around the phi node for resource pointers. Compare this with the described DXIL behavior, then determine whether the completed fix should add the validator-required capability or propagate the global-resource index through control flow.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Needs clarification
Newbie friendliness
45/100

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