[flang-commits] [flang] [flang][cuda] Update cuda data transfer rules for full managed assigment (PR #175243)
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Fri Jan 9 12:53:50 PST 2026
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-flang-fir-hlfir
Author: Valentin Clement (バレンタイン クレメン) (clementval)
<details>
<summary>Changes</summary>
---
Full diff: https://github.com/llvm/llvm-project/pull/175243.diff
2 Files Affected:
- (modified) flang/include/flang/Evaluate/tools.h (+1-2)
- (modified) flang/test/Lower/CUDA/cuda-data-transfer.cuf (+16)
``````````diff
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
``````````
</details>
https://github.com/llvm/llvm-project/pull/175243
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