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

[via flang-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-semantics

Author: Eugene Epshteyn (eugeneepshteyn)

<details>
<summary>Changes</summary>

Removed incorrect polymprphic check, added regression test.

Fixes #<!-- -->159149

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


2 Files Affected:

- (modified) flang/lib/Evaluate/check-expression.cpp (+14-25) 
- (modified) flang/test/Lower/force-temp.f90 (+43) 


``````````diff
diff --git a/flang/lib/Evaluate/check-expression.cpp b/flang/lib/Evaluate/check-expression.cpp
index 8931cbe485ac2..b35fff70cabaf 100644
--- a/flang/lib/Evaluate/check-expression.cpp
+++ b/flang/lib/Evaluate/check-expression.cpp
@@ -1493,32 +1493,21 @@ class CopyInOutExplicitInterface {
     return !actualTreatAsContiguous && dummyNeedsContiguity;
   }
 
-  // Returns true, if actual and dummy have polymorphic differences
   bool HavePolymorphicDifferences() const {
-    bool dummyIsAssumedRank{dummyObj_.type.attrs().test(
-        characteristics::TypeAndShape::Attr::AssumedRank)};
-    bool actualIsAssumedRank{semantics::IsAssumedRank(actual_)};
-    bool dummyIsAssumedShape{dummyObj_.type.attrs().test(
-        characteristics::TypeAndShape::Attr::AssumedShape)};
-    bool actualIsAssumedShape{semantics::IsAssumedShape(actual_)};
-    if ((actualIsAssumedRank && dummyIsAssumedRank) ||
-        (actualIsAssumedShape && dummyIsAssumedShape)) {
-      // Assumed-rank and assumed-shape arrays are represented by descriptors,
-      // so don't need to do polymorphic check.
-    } else if (!dummyObj_.ignoreTKR.test(common::IgnoreTKR::Type)) {
-      // flang supports limited cases of passing polymorphic to non-polimorphic.
-      // These cases require temporary of non-polymorphic type. (For example,
-      // the actual argument could be polymorphic array of child type,
-      // while the dummy argument could be non-polymorphic array of parent
-      // type.)
-      bool dummyIsPolymorphic{dummyObj_.type.type().IsPolymorphic()};
-      auto actualType{
-          characteristics::TypeAndShape::Characterize(actual_, fc_)};
-      bool actualIsPolymorphic{
-          actualType && actualType->type().IsPolymorphic()};
-      if (actualIsPolymorphic && !dummyIsPolymorphic) {
-        return true;
-      }
+    // These cases require temporary of non-polymorphic type. (For example,
+    // the actual argument could be polymorphic array of child type,
+    // while the dummy argument could be non-polymorphic array of parent
+    // type.)
+    if (dummyObj_.ignoreTKR.test(common::IgnoreTKR::Type)) {
+      return false;
+    }
+    auto actualType{characteristics::TypeAndShape::Characterize(actual_, fc_)};
+    if (actualType && actualType->type().IsPolymorphic() &&
+        !actualType->type().IsAssumedType() &&
+        !dummyObj_.IsPassedByDescriptor(/*isBindC*/ false)) {
+      // Not passing a descriptor, so will need to make a copy of the data
+      // with a proper type.
+      return true;
     }
     return false;
   }
diff --git a/flang/test/Lower/force-temp.f90 b/flang/test/Lower/force-temp.f90
index d9ba543d46313..e02463f700b45 100644
--- a/flang/test/Lower/force-temp.f90
+++ b/flang/test/Lower/force-temp.f90
@@ -27,6 +27,14 @@ subroutine pass_intent_out(buf)
       integer, intent(out) :: buf(5)
     end subroutine
   end interface
+
+  ! Used by call_s6() and others below
+  type base
+    integer :: i = -1
+  end type
+  type, extends (base) :: child
+    real :: r = -2.0
+  end type
 contains
   subroutine s1(buf)
 !CHECK-LABEL: func.func @_QMtestPs1
@@ -79,4 +87,39 @@ subroutine s5()
     p => x(::2) ! pointer to non-contiguous array section
     call pass_intent_out(p)
   end subroutine
+  subroutine call_s6()
+    interface
+      subroutine s6(b)
+        import :: base
+        type(base), intent(inout) :: b(:)
+      end subroutine s6
+    end interface
+    class(base), pointer :: pb(:)
+    type(child), target :: c(2)
+!CHECK-LABEL: func.func @_QMtestPcall_s6
+!CHECK-NOT: hlfir.copy_in
+!CHECK: fir.call @_QPs6
+!CHECK-NOT: hlfir.copy_out
+    pb => c
+    call s6(pb)
+  end subroutine call_s6
+  subroutine call_s7()
+    interface
+      subroutine s7(b1, b2, n)
+        import :: base
+        integer :: n
+        type(base), intent(inout) :: b1(n)
+        type(base), intent(inout) :: b2(*)
+      end subroutine
+    end interface
+    integer, parameter :: n = 7
+    class(base), allocatable :: c1(:), c2(:)
+!CHECK-LABEL: func.func @_QMtestPcall_s7
+!CHECK: hlfir.copy_in
+!CHECK: hlfir.copy_in
+!CHECK: fir.call @_QPs7
+!CHECK: hlfir.copy_out
+!CHECK: hlfir.copy_out
+    call s7(c1, c2, n)
+  end subroutine call_s7
 end module

``````````

</details>


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