[llvm] [AMDGPU][SplitModule] Handle !callees metadata (PR #108802)

[Juan Manuel Martinez Caamaño via llvm-commits]

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@@ -476,12 +486,36 @@ void SplitGraph::Node::visitAllDependencies(
   }
 }
 
+/// Checks if \p I has MD_callees and if it does, parse it and put the function
+/// in \p Callees.
+///
+/// \returns true if there was metadata and it was parsed correctly. false if
+/// there was no MD or if it contained unknown entries.
+static bool handleCalleesMD(const Instruction &I,
+                            SmallVector<Function *> &Callees) {
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jmmartinez wrote:

```suggestion
                            SmallVectorImpl<Function *> &Callees) {
```

https://github.com/llvm/llvm-project/pull/108802