[llvm] [MergeFunctions] Add support to run the pass over a set of function pointers (PR #111045)

[Nikita Popov via llvm-commits]

================
@@ -467,9 +488,16 @@ bool MergeFunctions::runOnModule(Module &M) {
   return Changed;
 }
 
+DenseMap<Function *, Function *>
+MergeFunctions::runOnFunctions(ArrayRef<Function *> F) {
+  bool MergeResult = this->run(F);
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nikic wrote:

```suggestion
  [[maybe_unused]] bool MergeResult = this->run(F);
```
Otherwise this is going to warn in release build.

https://github.com/llvm/llvm-project/pull/111045