microsoft / microsoft/DirectXShaderCompiler

Declare SV_VertexID as float only get validation error

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bug diagnostic tech-debt
Dominant language
C++
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Description

Description

SV_VertexID should be a uint.
But declare it as float only get validation error.
Not compile error.

Steps to Reproduce

compile with -Tvs_6_0

float4 main(float V : SV_VertextID) : SV_Position {
return V;
}

https://godbolt.org/z/ahe1fjsEM

Actual Behavior

It should be a compile error instead of validation error.

Environment

  • DXC version 1.7.2207
  • Host Operating System Windows

Contributor guide

Open the contributing guide

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 by reproducing the shader with DXC using -Tvs_6_0 and compare the compiler and validation stages, using the linked Compiler Explorer example. Trace where the SV_VertexID type is checked; done means declaring it as float produces a compile error rather than only a validation error.

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
42/100

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