[llvm] [DirectX] Implement DXILResourceImplicitBinding pass (PR #138043)

[Ashley Coleman via llvm-commits]

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@@ -998,6 +998,61 @@ void DXILResourceBindingInfo::populate(Module &M, DXILResourceTypeMap &DRTM) {
   }
 }
 
+// returns false if binding could not be found in given space
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V-FEXrt wrote:

nit: 
```suggestion
// returns nullopt if binding could not be found in given space
```

https://github.com/llvm/llvm-project/pull/138043