[flang-commits] [flang] [flang][cuda] Update cuda data transfer rules for full managed assigment (PR #175243)

[Valentin Clement バレンタイン クレメン via flang-commits]

https://github.com/clementval created https://github.com/llvm/llvm-project/pull/175243

None

>From 27238c70252680d8cbc6832bc503640dd882c931 Mon Sep 17 00:00:00 2001
From: Valentin Clement <clementval at gmail.com>
Date: Fri, 9 Jan 2026 12:52:21 -0800
Subject: [PATCH] [flang][cuda] Update cuda data transfer rules for full
 managed assignment

---
 flang/include/flang/Evaluate/tools.h         |  3 +--
 flang/test/Lower/CUDA/cuda-data-transfer.cuf | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/flang/include/flang/Evaluate/tools.h b/flang/include/flang/Evaluate/tools.h
index ea26a0ee9da7a..6a424f2cbb04e 100644
--- a/flang/include/flang/Evaluate/tools.h
+++ b/flang/include/flang/Evaluate/tools.h
@@ -1352,8 +1352,7 @@ inline bool IsCUDADataTransfer(const A &lhs, const B &rhs) {
   // Special cases performed on the host:
   // - Only managed or unifed symbols are involved on RHS and LHS.
   // - LHS is managed or unified and the RHS is host only.
-  if ((lhsNbManagedSymbols >= 1 && rhsNbManagedSymbols == 1 &&
-          rhsNbSymbols == 1) ||
+  if ((lhsNbManagedSymbols >= 1 && rhsNbManagedSymbols == rhsNbSymbols) ||
       (lhsNbManagedSymbols >= 1 && rhsNbSymbols == 0)) {
     return false;
   }
diff --git a/flang/test/Lower/CUDA/cuda-data-transfer.cuf b/flang/test/Lower/CUDA/cuda-data-transfer.cuf
index 058e2506c1d53..0c14f960bbb29 100644
--- a/flang/test/Lower/CUDA/cuda-data-transfer.cuf
+++ b/flang/test/Lower/CUDA/cuda-data-transfer.cuf
@@ -588,3 +588,19 @@ end subroutine
 ! CHECK: %{{.*}} = cuf.alloc !fir.type<_QMmod1Tt3{spheres:!fir.box<!fir.heap<!fir.array<?x!fir.type<_QMmod1Ts{c:!fir.array<3xf32>}>>>>}> {bindc_name = "t", data_attr = #cuf.cuda<managed>, uniq_name = "_QFsub30Et"} -> !fir.ref<!fir.type<_QMmod1Tt3{spheres:!fir.box<!fir.heap<!fir.array<?x!fir.type<_QMmod1Ts{c:!fir.array<3xf32>}>>>>}>>
 ! CHECK: hlfir.assign 
 ! CHECK-NOT: cuf.data_transfer
+
+! Test that assigment with onlt managed variables on both rhs and lhs is done
+! on the host.
+
+subroutine sub31()
+  type :: t30
+    real, managed, allocatable :: q(:)
+  end type
+  type(t30), managed, allocatable :: x(:)
+  x(4)%q = x(3)%q
+end subroutine
+
+! CHECK-LABEL: func.func @_QPsub31()
+! CHECK: cuf.alloc !fir.box<!fir.heap<!fir.array<?x!fir.type<_QFsub31Tt30{q:!fir.box<!fir.heap<!fir.array<?xf32>>>}>>>> 
+! CHECK: hlfir.assign 
+! CHECK-NOT: cuf.data_transfer