DXIL link validation error with exported matrix function

I encountered a validation error with a DXIL library, after it was successfully compiled to DXIL, during the linking step. As far as I know, the validation error only happens when the linking is done with a lib profile also. This simplified repro links with itself, which I think should be legal and it shows the error simply. Of course I was linking it with other DXIL objects in the real life case.

export float4x4 to4x4(float3x4 source)
{
    return float4x4(source[0], source[1], source[2], float4(0.0f, 0.0f, 0.0f, 1.0f));
}

Compile:
$ ../../../../Downloads/dxc_2024_03_29/bin/x64/dxc.exe ./export.hlsl -T lib_6_6 -Fo ./export.dxil

Link:
$ ../../../../Downloads/dxc_2024_03_29/bin/x64/dxc.exe -T lib_6_6 -link "./export.dxil"

Link failed:
error: validation errors
Function: ?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@@Z: error: ExtractValue should only be used on dxil struct types and cmpxchg.
note: at '%2 = extractvalue %class.matrix.float.3.4 %0, 0, 0' in block '#0' of function '?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@
@Z'.
Function: ?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@@Z: error: ExtractValue should only be used on dxil struct types and cmpxchg.
note: at '%7 = extractvalue %class.matrix.float.3.4 %0, 0, 1' in block '#0' of function '?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@
@Z'.
Function: ?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@@Z: error: ExtractValue should only be used on dxil struct types and cmpxchg.
note: at '%12 = extractvalue %class.matrix.float.3.4 %0, 0, 2' in block '#0' of function '?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@
@@Z'.
Function: ?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@@Z: error: Instructions must be of an allowed type.
note: at '%21 = insertvalue %class.matrix.float.4.4 undef, <4 x float> %20, 0, 0' in block '#0' of function '?to4x4@@YA?AV?$matrix@M$03$03@
@V?$matrix@M$02$03@@@Z'.
Function: ?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@@Z: error: Instructions must be of an allowed type.
note: at '%26 = insertvalue %class.matrix.float.4.4 %21, <4 x float> %25, 0, 1' in block '#0' of function '?to4x4@@YA?AV?$matrix@M$03$03@@V
?$matrix@M$02$03@@@Z'.
Function: ?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@@Z: error: Instructions must be of an allowed type.
note: at '%31 = insertvalue %class.matrix.float.4.4 %26, <4 x float> %30, 0, 2' in block '#0' of function '?to4x4@@YA?AV?$matrix@M$03$03@@V
?$matrix@M$02$03@@@Z'.
Function: ?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@@Z: error: Instructions must be of an allowed type.
note: at '%32 = insertvalue %class.matrix.float.4.4 %31, <4 x float> <float 0.000000e+00, float 0.000000e+00, float 0.000000e+00, float 1.00
0000e+00>, 0, 3' in block '#0' of function '?to4x4@@YA?AV?$matrix@M$03$03@@V?$matrix@M$02$03@@@Z'.
Validation failed.

Environment
$ ../../../../Downloads/dxc_2024_03_29/bin/x64/dxc.exe --version
dxcompiler.dll: 1.8 - 1.8.2403.37 (11e1318c3); dxil.dll: 1.8(101.8.2403.24)

Windows 10 Enterprise v22H2

Start by reproducing the issue with the provided dxc compile and -link commands using the exported matrix-function HLSL example. Trace the DXIL link and validation path to determine why the linked library rejects the matrix extractvalue and insertvalue instructions; done means the repro links successfully with the lib_6_6 profile and passes validation.