[flang-commits] [flang] [flang][Evaluate] Add `AsGenericExpr` that takes std::optional (PR #81264)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-semantics

Author: Krzysztof Parzyszek (kparzysz)

<details>
<summary>Changes</summary>

`AsGenericExpr` already returns optional Expr. Making it accept an optional Expr as input would reduce the number of necessary checks when handling frequent optional values in evaluator.

---
Full diff: https://github.com/llvm/llvm-project/pull/81264.diff


1 Files Affected:

- (modified) flang/include/flang/Evaluate/tools.h (+8) 


``````````diff
diff --git a/flang/include/flang/Evaluate/tools.h b/flang/include/flang/Evaluate/tools.h
index d257da1a709642..f7f155a5da9e13 100644
--- a/flang/include/flang/Evaluate/tools.h
+++ b/flang/include/flang/Evaluate/tools.h
@@ -148,6 +148,14 @@ inline Expr<SomeType> AsGenericExpr(Expr<SomeType> &&x) { return std::move(x); }
 std::optional<Expr<SomeType>> AsGenericExpr(DataRef &&);
 std::optional<Expr<SomeType>> AsGenericExpr(const Symbol &);
 
+// Propagate std::optional from input to output.
+template <typename A>
+std::optional<Expr<SomeType>> AsGenericExpr(std::optional<A> &&x) {
+  if (!x)
+    return std::nullopt;
+  return AsGenericExpr(std::move(*x));
+}
+
 template <typename A>
 common::IfNoLvalue<Expr<SomeKind<ResultType<A>::category>>, A> AsCategoryExpr(
     A &&x) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/81264