[clang] [HLSL] Avoid putting the byval attribute on out and inout parameters (PR #150495)

[Joshua Batista via cfe-commits]

bob80905 wrote:

Looked over the DXC codebase and didn't find any hits on deadonreturn, so yeah I think such a test wouldn't make sense.
But, then, wouldn't this be a better approach?

```


        // Depending on the ABI, this may be either a byval or a dead_on_return
        // argument.
        if (AI.getIndirectByVal()) {
            if (auto ParamABI = FI.getExtParameterInfo(ArgNo).getABI();
              ParamABI != ParameterABI::HLSLOut &&
              ParamABI != ParameterABI::HLSLInOut) {
                  Attrs.addByValAttr(getTypes().ConvertTypeForMem(ParamType));
            }
        } else {
          // Add dead_on_return when the object's lifetime ends in the callee.
          // This includes trivially-destructible objects, as well as objects
          // whose destruction / clean-up is carried out within the callee
          // (e.g., Obj-C ARC-managed structs, MSVC callee-destroyed objects).
          if (!ParamType.isDestructedType() || !ParamType->isRecordType() ||
              ParamType->castAs<RecordType>()
                  ->getDecl()
                  ->isParamDestroyedInCallee())
            Attrs.addAttribute(llvm::Attribute::DeadOnReturn);
        }
```
If DeadOnReturn is not relevant in HLSL, then this change would be affecting other compilation behavior outside of HLSL, right?


https://github.com/llvm/llvm-project/pull/150495