Add NormalizeFlattenedBinaryOperation normalization (phate#728)

Co-authored-by: HKrogstie <[email protected]>

jlm/rvsdg/binary.cpp

@@ -502,6 +502,14 @@ flattened_binary_op::reduce(
   JLM_ASSERT(!Region::Contains<flattened_binary_op>(*region, true));
 }
 
+std::optional<std::vector<rvsdg::output *>>
+NormalizeFlattenedBinaryOperation(
+    const flattened_binary_op & operation,
+    const std::vector<rvsdg::output *> & operands)
+{
+  return NormalizeBinaryOperation(operation.bin_operation(), operands);
+}
+
 }
 
 jlm::rvsdg::node_normal_form *

jlm/rvsdg/binary.hpp

@@ -269,6 +269,23 @@ class flattened_binary_op final : public SimpleOperation
   std::unique_ptr<BinaryOperation> op_;
 };
 
+/**
+ * \brief Applies the reductions of the binary operation represented by the flattened binary
+ * operation.
+ *
+ * @param operation The flattened binary operation on which the transformation is performed.
+ * @param operands The operands of the flattened binary node.
+ *
+ * @return If the normalization could be applied, then the results of the flattened binary operation
+ * after the transformation. Otherwise, std::nullopt.
+ *
+ * \see NormalizeBinaryOperation()
+ */
+std::optional<std::vector<rvsdg::output *>>
+NormalizeFlattenedBinaryOperation(
+    const flattened_binary_op & operation,
+    const std::vector<rvsdg::output *> & operands);
+
 /* binary flags operators */
 
 static constexpr enum BinaryOperation::flags