[flang-commits] [flang] [flang] Fixed regression in copy-in/copy-out (PR #161259)

[via flang-commits]

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@@ -1572,28 +1553,35 @@ class CopyInOutExplicitInterface {
 // procedures with explicit interface, it's expected that "dummy" is not null.
 // For procedures with implicit interface dummy may be null.
 //
+// Returns std::optional<bool> indicating whether the copy is known to be
+// needed (true) or not needed (false); returns std::nullopt if the necessity
+// of the copy is undetermined.
+//
 // Note that these copy-in and copy-out checks are done from the caller's
 // perspective, meaning that for copy-in the caller need to do the copy
 // before calling the callee. Similarly, for copy-out the caller is expected
 // to do the copy after the callee returns.
-bool MayNeedCopy(const ActualArgument *actual,
+std::optional<bool> ActualArgNeedsCopy(const ActualArgument *actual,
     const characteristics::DummyArgument *dummy, FoldingContext &fc,
     bool forCopyOut) {
+  constexpr auto unknown = std::nullopt;
   if (!actual) {
-    return false;
+    return unknown;
   }
   if (actual->isAlternateReturn()) {
-    return false;
+    return unknown;
   }
   const auto *dummyObj{dummy
           ? std::get_if<characteristics::DummyDataObject>(&dummy->u)
           : nullptr};
   const bool forCopyIn = !forCopyOut;
   if (!evaluate::IsVariable(*actual)) {
-    // Actual argument expressions that aren’t variables are copy-in, but
-    // not copy-out.
+    // Expressions are copy-in, but not copy-out.
     return forCopyIn;
   }
+  auto maybeContigActual{IsContiguous(*actual, fc)};
+  bool isContiguousActual{
+      maybeContigActual.has_value() && maybeContigActual.value()};
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jeanPerier wrote:

nit: isContiguousActual{IsContiguous(*actual, fc).value_or(false)}';

https://github.com/llvm/llvm-project/pull/161259