[Matrix] Implement a ICK_HLSL_Matrix_Splat

[farzonl]

Because there is no ICK_HLSL_Matrix_Splat and there is a ICK_HLSL_Vector_Splat We have a case where something should be ambigious and it is not. The case looks like this:
https://godbolt.org/z/haaW4c6Pa

void matOrVec(float4 F) {}
void matOrVec(float2x2 F) {}

export void Case9() {
#if ERROR
    matOrVec(2.0); // Ambiguous!
#endif
}

To fix this we need to implement a matrix splat.

[VikramAditya144]

Hey @farzonl , I’m new to LLVM and would like to work on this issue. Could I take it?

[farzonl]

Sorry this is a bit involved because we don’t want matrix splat cases to be very permissive. Requires us to also verify and possibly define the spec.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Farzon Lotfi (farzonl)

Because there is no `ICK_HLSL_Matrix_Splat` and there is a `ICK_HLSL_Vector_Splat` We have a case where something should be ambigious and it is not. The case looks like this: https://godbolt.org/z/haaW4c6Pa

void matOrVec(float4 F) {}
void matOrVec(float2x2 F) {}

export void Case9() {
#if ERROR
    matOrVec(2.0); // Ambiguous!
#endif
}

To fix this we need to implement a matrix splat.