microsoft / microsoft/DirectXShaderCompiler
WaveMatch with a vector input value
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- Dominant language
- C++
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- Merged PRs (30d)
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Description
The spec. of SM6.5 says:
uint4 WaveMatch( val )
...
val can be any expression which evaluates to any of the currently supported primitive data types (e.g. float4, uint2, etc.).
in https://microsoft.github.io/DirectX-Specs/d3d/HLSL_ShaderModel6_5.html
However, when I use WaveMatch(uint4), it shows a validation error:
1>Content\Shaders/ImpactRange.hlsli(59,18): error G315CBA34: Instructions must be of an allowed type.
1>note: at '%1219 = insertvalue %dx.types.fouri32 %1214, i32 %1218, 0' in block '#33' of function 'main'.
The error is only reported by the debug mode (disable optimization and enable debug info). Under release mode, it is silent. Anyway, after seeing this error, I even doubt whether dxcompiler really allows and has implemented uint4 val following the spec. description.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the WaveMatch(uint4) use at Content\Shaders\ImpactRange.hlsli:59 and compare it with the SM 6.5 specification. Reproduce the validation error with optimization disabled and debug information enabled, then determine whether the compiler rejects a supported vector input; done means the implementation behavior is confirmed against the specification.
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
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 38/100