[llvm] [SCEV] Move getSCEVAtExit() into ScalarEvolution (PR #225102)

[Florian Hahn via llvm-commits]

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@@ -968,6 +968,18 @@ class ScalarEvolution {
   /// This is a convenience function which does getSCEVAtScope(getSCEV(V), L).
   LLVM_ABI SCEVUse getSCEVAtScope(Value *V, const Loop *L);
 
+  /// Return the SCEV expression at the specified loop exit. Returns the
+  /// original value if not more precisely value can be computed.
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fhahn wrote:

```suggestion
  /// original value if no more precise value can be computed.
```

https://github.com/llvm/llvm-project/pull/225102