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

Eugene Epshteyn via flang-commits flang-commits at lists.llvm.org
Tue Sep 30 11:59:44 PDT 2025


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

>From 632ed7be408faa9fba2e0db112fa1002c2f351b0 Mon Sep 17 00:00:00 2001
From: Eugene Epshteyn <eepshteyn at nvidia.com>
Date: Mon, 29 Sep 2025 13:55:05 -0400
Subject: [PATCH 1/7] [flang] Fixed regression in copy-in/copy-out

Removed incorrect polymprphic check, added regression test.

Fixes #159149
---
 flang/lib/Evaluate/check-expression.cpp | 33 -------------------------
 flang/test/Lower/force-temp.f90         | 24 ++++++++++++++++++
 2 files changed, 24 insertions(+), 33 deletions(-)

diff --git a/flang/lib/Evaluate/check-expression.cpp b/flang/lib/Evaluate/check-expression.cpp
index 8931cbe485ac2..af3554c78b3ad 100644
--- a/flang/lib/Evaluate/check-expression.cpp
+++ b/flang/lib/Evaluate/check-expression.cpp
@@ -1493,36 +1493,6 @@ 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;
-      }
-    }
-    return false;
-  }
-
   bool HaveArrayOrAssumedRankArgs() const {
     bool dummyTreatAsArray{dummyObj_.ignoreTKR.test(common::IgnoreTKR::Rank)};
     return IsArrayOrAssumedRank(actual_) &&
@@ -1611,9 +1581,6 @@ bool MayNeedCopy(const ActualArgument *actual,
     if (check.HaveContiguityDifferences()) {
       return true;
     }
-    if (check.HavePolymorphicDifferences()) {
-      return true;
-    }
   } else { // Implicit interface
     if (ExtractCoarrayRef(*actual)) {
       // Coindexed actual args may need copy-in and copy-out with implicit
diff --git a/flang/test/Lower/force-temp.f90 b/flang/test/Lower/force-temp.f90
index d9ba543d46313..5a5e7d0abec5e 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 s6() and call_s6()
+  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 +87,20 @@ subroutine s5()
     p => x(::2) ! pointer to non-contiguous array section
     call pass_intent_out(p)
   end subroutine
+  subroutine call_s6()
+!CHECK-LABEL: func.func @_QMtestPcall_s6
+!CHECK-NOT: hlfir.copy_in
+!CHECK: fir.call @_QMtestPs6
+!CHECK-NOT: hlfir.copy_out
+    class(base), pointer :: pb(:)
+    type(child), target :: c(2)
+
+    c = (/(child (i, real(i*2)), i=1,size(c))/)
+    pb => c
+    call s6(pb)
+  end subroutine call_s6
+  subroutine s6(b)
+    type(base), intent(inout) :: b(:)
+    b%i = 42
+  end subroutine s6
 end module

>From 9189ede230e566442f5514a145e334b10d1255df Mon Sep 17 00:00:00 2001
From: Eugene Epshteyn <eepshteyn at nvidia.com>
Date: Tue, 30 Sep 2025 12:31:28 -0400
Subject: [PATCH 2/7] Restore HavePolymorphicDifferences(), but with different
 checks

---
 flang/lib/Evaluate/check-expression.cpp | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/flang/lib/Evaluate/check-expression.cpp b/flang/lib/Evaluate/check-expression.cpp
index af3554c78b3ad..9337bb62387cc 100644
--- a/flang/lib/Evaluate/check-expression.cpp
+++ b/flang/lib/Evaluate/check-expression.cpp
@@ -1493,6 +1493,25 @@ class CopyInOutExplicitInterface {
     return !actualTreatAsContiguous && dummyNeedsContiguity;
   }
 
+  bool HavePolymorphicDifferences() const {
+    // 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_)};
+    bool actualIsPolymorphic{
+        actualType && actualType->type().IsPolymorphic()};
+    if (actualIsPolymorphic && !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;
+  }
+
   bool HaveArrayOrAssumedRankArgs() const {
     bool dummyTreatAsArray{dummyObj_.ignoreTKR.test(common::IgnoreTKR::Rank)};
     return IsArrayOrAssumedRank(actual_) &&
@@ -1581,6 +1600,9 @@ bool MayNeedCopy(const ActualArgument *actual,
     if (check.HaveContiguityDifferences()) {
       return true;
     }
+    if (check.HavePolymorphicDifferences()) {
+      return true;
+    }
   } else { // Implicit interface
     if (ExtractCoarrayRef(*actual)) {
       // Coindexed actual args may need copy-in and copy-out with implicit

>From f572da2e5acee10a427306c14c998b7baee1de96 Mon Sep 17 00:00:00 2001
From: Eugene Epshteyn <eepshteyn at nvidia.com>
Date: Tue, 30 Sep 2025 13:01:05 -0400
Subject: [PATCH 3/7] Tweaked the change to ignore assumed type in polymorphic
 check

---
 flang/lib/Evaluate/check-expression.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/flang/lib/Evaluate/check-expression.cpp b/flang/lib/Evaluate/check-expression.cpp
index 9337bb62387cc..60742f6aed7a7 100644
--- a/flang/lib/Evaluate/check-expression.cpp
+++ b/flang/lib/Evaluate/check-expression.cpp
@@ -1502,9 +1502,9 @@ class CopyInOutExplicitInterface {
       return false;
     }
     auto actualType{characteristics::TypeAndShape::Characterize(actual_, fc_)};
-    bool actualIsPolymorphic{
-        actualType && actualType->type().IsPolymorphic()};
-    if (actualIsPolymorphic && !dummyObj_.IsPassedByDescriptor(/*isBindC*/false)) {
+    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;

>From 91f9e67bdef64f402cb2ca72a7d95d757ca59977 Mon Sep 17 00:00:00 2001
From: Eugene Epshteyn <eepshteyn at nvidia.com>
Date: Tue, 30 Sep 2025 13:01:27 -0400
Subject: [PATCH 4/7] clang-format

---
 flang/lib/Evaluate/check-expression.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/flang/lib/Evaluate/check-expression.cpp b/flang/lib/Evaluate/check-expression.cpp
index 60742f6aed7a7..b35fff70cabaf 100644
--- a/flang/lib/Evaluate/check-expression.cpp
+++ b/flang/lib/Evaluate/check-expression.cpp
@@ -1504,7 +1504,7 @@ class CopyInOutExplicitInterface {
     auto actualType{characteristics::TypeAndShape::Characterize(actual_, fc_)};
     if (actualType && actualType->type().IsPolymorphic() &&
         !actualType->type().IsAssumedType() &&
-        !dummyObj_.IsPassedByDescriptor(/*isBindC*/false)) {
+        !dummyObj_.IsPassedByDescriptor(/*isBindC*/ false)) {
       // Not passing a descriptor, so will need to make a copy of the data
       // with a proper type.
       return true;

>From d60edf8b2251820f617a0e9bce942166ea651b88 Mon Sep 17 00:00:00 2001
From: Eugene Epshteyn <eepshteyn at nvidia.com>
Date: Tue, 30 Sep 2025 14:21:08 -0400
Subject: [PATCH 5/7] Replaced s6() with an interface, since only care about
 the call

---
 flang/test/Lower/force-temp.f90 | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/flang/test/Lower/force-temp.f90 b/flang/test/Lower/force-temp.f90
index 5a5e7d0abec5e..cb06011f08ce2 100644
--- a/flang/test/Lower/force-temp.f90
+++ b/flang/test/Lower/force-temp.f90
@@ -88,9 +88,15 @@ subroutine s5()
     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
 !CHECK-LABEL: func.func @_QMtestPcall_s6
 !CHECK-NOT: hlfir.copy_in
-!CHECK: fir.call @_QMtestPs6
+!CHECK: fir.call @_QPs6
 !CHECK-NOT: hlfir.copy_out
     class(base), pointer :: pb(:)
     type(child), target :: c(2)
@@ -99,8 +105,4 @@ subroutine call_s6()
     pb => c
     call s6(pb)
   end subroutine call_s6
-  subroutine s6(b)
-    type(base), intent(inout) :: b(:)
-    b%i = 42
-  end subroutine s6
 end module

>From 1e698038ba712c6d40ef32e384a69144d4304a4b Mon Sep 17 00:00:00 2001
From: Eugene Epshteyn <eepshteyn at nvidia.com>
Date: Tue, 30 Sep 2025 14:36:42 -0400
Subject: [PATCH 6/7] New test to check for copy-in/out for potential slicing
 test

---
 flang/test/Lower/force-temp.f90 | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/flang/test/Lower/force-temp.f90 b/flang/test/Lower/force-temp.f90
index cb06011f08ce2..39d83c7c34a18 100644
--- a/flang/test/Lower/force-temp.f90
+++ b/flang/test/Lower/force-temp.f90
@@ -94,15 +94,32 @@ subroutine s6(b)
         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
-    class(base), pointer :: pb(:)
-    type(child), target :: c(2)
-
-    c = (/(child (i, real(i*2)), i=1,size(c))/)
     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

>From 94f69eda0ee72ab0dae48313f07d30bd5a3f74ee Mon Sep 17 00:00:00 2001
From: Eugene Epshteyn <eepshteyn at nvidia.com>
Date: Tue, 30 Sep 2025 14:59:30 -0400
Subject: [PATCH 7/7] Tweaked test comment

---
 flang/test/Lower/force-temp.f90 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/flang/test/Lower/force-temp.f90 b/flang/test/Lower/force-temp.f90
index 39d83c7c34a18..e02463f700b45 100644
--- a/flang/test/Lower/force-temp.f90
+++ b/flang/test/Lower/force-temp.f90
@@ -28,7 +28,7 @@ subroutine pass_intent_out(buf)
     end subroutine
   end interface
 
-  ! Used by s6() and call_s6()
+  ! Used by call_s6() and others below
   type base
     integer :: i = -1
   end type



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