[IPO] Remove an unused function declaration

The corresponding definition doesn't seem to have existed every since
the declaration was introduced on Jul 8, 2019 in commit
accd3e87478eb75d455e016500ef3d2ddbeca82d.

FWIW, we do have AAReturnedValuesImpl::getAssumedUniqueReturnValue
declared and defined in Attributor.cpp.

diff --git a/llvm/include/llvm/Transforms/IPO/Attributor.h b/llvm/include/llvm/Transforms/IPO/Attributor.h
index f469707..ec10c5c 100644 (file)
--- a/llvm/include/llvm/Transforms/IPO/Attributor.h
+++ b/llvm/include/llvm/Transforms/IPO/Attributor.h
@@ -3142,11 +3142,6 @@ struct AAReturnedValues
     : public IRAttribute<Attribute::Returned, AbstractAttribute> {
   AAReturnedValues(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
 
-  /// Return an assumed unique return value if a single candidate is found. If
-  /// there cannot be one, return a nullptr. If it is not clear yet, return the
-  /// Optional::NoneType.
-  Optional<Value *> getAssumedUniqueReturnValue(Attributor &A) const;
-
   /// Check \p Pred on all returned values.
   ///
   /// This method will evaluate \p Pred on returned values and return