[clang] [llvm] [HLSL][SPIRV]Add SPIRV generation for HLSL dot (PR #104656)

[Farzon Lotfi via llvm-commits]

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@@ -1446,6 +1449,67 @@ bool SPIRVInstructionSelector::selectRsqrt(Register ResVReg,
       .constrainAllUses(TII, TRI, RBI);
 }
 
+// Since there is no integer dot implementation, expand by piecewise multiplying
----------------
farzonl wrote:

```suggestion
// Since there is no integer dot implementation until spirv 1.6, expand by piecewise multiplying
```

https://github.com/llvm/llvm-project/pull/104656