[flang-commits] [flang] [flang] Disable copy-out to INTENT(IN) args (PR #192382)

[Eugene Epshteyn via flang-commits]

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@@ -1649,6 +1649,17 @@ std::optional<bool> ActualArgNeedsCopy(const ActualArgument *actual,
     // Expressions are copy-in, but not copy-out.
     return forCopyIn;
   }
+  if (forCopyOut) {
+    // If the actual argument's base object has INTENT(IN) in the caller's
+    // context, copy-out would violate the read-only semantics of INTENT(IN).
+    if (const Expr<SomeType> *expr{actual->UnwrapExpr()}) {
+      if (const Symbol *symbol{GetFirstSymbol(*expr)}) {
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eugeneepshteyn wrote:

Yes, very good point. Also I think for `integer, intent(in), pointer :: pi(:)`, the intent "guards" pointer association, not the values.

Also, a few Fujitsu tests failed, including [0070_0001](https://github.com/fujitsu/compiler-test-suite/blob/main/Fortran/0070/0070_0001.f90), which is similar to your example. Need to make the checks more targeted.

https://github.com/llvm/llvm-project/pull/192382