`as` casts on integer constant swizzles result in invalid module bitcode (or assert in debug)

Description
Compiling a compute shader that we generate from Dawn (Chromium WebGPU implementation) fails with "Invalid record".

Steps to Reproduce

Given the following compute shader:

01: Texture2DMS<float4> tint_symbol : register(t0);
02: Texture2DMS<float4> tint_symbol_1 : register(t1);
03: 
04: RWByteAddressBuffer tint_symbol_5 : register(u2);
05: 
06: [numthreads(1, 1, 1)]
07: void tint_symbol_6() {
08:   {
09:     for(int tint_symbol_7 = 0; (tint_symbol_7 < 4); tint_symbol_7 = (tint_symbol_7 + 1)) {
10:       tint_symbol_5.Store((4u * uint(tint_symbol_7)), asuint(tint_symbol.Load((0).xx, tint_symbol_7).x));
11:       tint_symbol_5.Store((16u + (4u * uint(tint_symbol_7))), asuint(tint_symbol_1.Load(int3(0, 0, 0), tint_symbol_7).x));
12:     }
13:   }
14:   return;
15: }
16: 

When compiling with DXC:

C:\src\dawn>.\out\debug\dxc /T cs_6_0 /E tint_symbol_6 1976.hlsl
1976.hlsl:11:89: warning: implicit truncation of vector type [-Wconversion]
      tint_symbol_5.Store((16u + (4u * uint(tint_symbol_7))), asuint(tint_symbol_1.Load(int3(0, 0, 0), tint_symbol_7).x));
                                                                                        ^
error: validation errors
Invalid record
Validation failed.

Note that the warning is not important. In fact, commenting out line 11 still produces and error. However, commenting out line 10, DXC manages to compile correctly.

Actual Behavior
The shader should compile.

Environment

• DXC version: dxcompiler.dll: 1.7 - 1.7.2212.40 (e043f4a12); dxil.dll: 1.7(101.7.2212.36)
• Host Operating System: Windows 10

Start by reproducing the provided HLSL compute shader with the specified DXC version and compare validation with line 10 present or removed. Trace the DXC validation path for the generated module; done means the shader compiles without an “Invalid record” error or debug assertion.