[flang-commits] [flang] [flang][cuda] Handle associated variables in data transfer (PR #163668)

[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/163668

None

>From cbdf63428ba3d29e2087b6e234815e0b07e614da Mon Sep 17 00:00:00 2001
From: Valentin Clement <clementval at gmail.com>
Date: Wed, 15 Oct 2025 17:46:50 -0700
Subject: [PATCH] [flang][cuda] Handle associated variables in data transfer

---
 flang/include/flang/Evaluate/tools.h          | 11 +---------
 flang/lib/Evaluate/tools.cpp                  | 12 +++++++++++
 .../CUDA/cuda-associate-data-transfer.cuf     | 21 +++++++++++++++++++
 3 files changed, 34 insertions(+), 10 deletions(-)
 create mode 100644 flang/test/Lower/CUDA/cuda-associate-data-transfer.cuf

diff --git a/flang/include/flang/Evaluate/tools.h b/flang/include/flang/Evaluate/tools.h
index d8d0956369e40..20a091918dc56 100644
--- a/flang/include/flang/Evaluate/tools.h
+++ b/flang/include/flang/Evaluate/tools.h
@@ -1289,16 +1289,7 @@ bool CheckForCoindexedObject(parser::ContextualMessages &,
     const std::optional<ActualArgument> &, const std::string &procName,
     const std::string &argName);
 
-inline bool IsCUDADeviceSymbol(const Symbol &sym) {
-  if (const auto *details =
-          sym.GetUltimate().detailsIf<semantics::ObjectEntityDetails>()) {
-    if (details->cudaDataAttr() &&
-        *details->cudaDataAttr() != common::CUDADataAttr::Pinned) {
-      return true;
-    }
-  }
-  return false;
-}
+bool IsCUDADeviceSymbol(const Symbol &sym);
 
 inline bool IsCUDAManagedOrUnifiedSymbol(const Symbol &sym) {
   if (const auto *details =
diff --git a/flang/lib/Evaluate/tools.cpp b/flang/lib/Evaluate/tools.cpp
index b927fa3cc7ed7..bd06acc21e47f 100644
--- a/flang/lib/Evaluate/tools.cpp
+++ b/flang/lib/Evaluate/tools.cpp
@@ -1153,6 +1153,18 @@ bool HasCUDAImplicitTransfer(const Expr<SomeType> &expr) {
   return (hasConstant || (hostSymbols.size() > 0)) && deviceSymbols.size() > 0;
 }
 
+bool IsCUDADeviceSymbol(const Symbol &sym) {
+  if (const auto *details =
+          sym.GetUltimate().detailsIf<semantics::ObjectEntityDetails>()) {
+    return details->cudaDataAttr() &&
+        *details->cudaDataAttr() != common::CUDADataAttr::Pinned;
+  } else if (const auto *details =
+                 sym.GetUltimate().detailsIf<semantics::AssocEntityDetails>()) {
+    return GetNbOfCUDADeviceSymbols(details->expr()) > 0;
+  }
+  return false;
+}
+
 // HasVectorSubscript()
 struct HasVectorSubscriptHelper
     : public AnyTraverse<HasVectorSubscriptHelper, bool,
diff --git a/flang/test/Lower/CUDA/cuda-associate-data-transfer.cuf b/flang/test/Lower/CUDA/cuda-associate-data-transfer.cuf
new file mode 100644
index 0000000000000..2b25e55e5df35
--- /dev/null
+++ b/flang/test/Lower/CUDA/cuda-associate-data-transfer.cuf
@@ -0,0 +1,21 @@
+! RUN: bbc -emit-hlfir -fopenacc -fcuda %s -o - | FileCheck %s
+
+! Test detection of CUDA Fortran data transfer in presence of associuate
+! statement.
+
+module m
+  real(8), device, dimension(10,10,10) :: d
+end module m
+
+subroutine foo
+  use m
+  !@CUF associate(d1 => d)
+  d1 = 0.0
+  !@CUF end associate
+end subroutine
+
+! CHECK-LABEL: func.func @_QPfoo()
+! CHECK: %[[D:.*]] = fir.address_of(@_QMmEd) : !fir.ref<!fir.array<10x10x10xf64>>
+! CHECK: %[[D_DECL:.*]]:2 = hlfir.declare %[[D]](%{{.*}}) {data_attr = #cuf.cuda<device>, uniq_name = "_QMmEd"} : (!fir.ref<!fir.array<10x10x10xf64>>, !fir.shape<3>) -> (!fir.ref<!fir.array<10x10x10xf64>>, !fir.ref<!fir.array<10x10x10xf64>>)
+! CHECK: %[[D1_DECL:.*]]:2 = hlfir.declare %[[D_DECL]]#0(%4) {uniq_name = "_QFfooEd1"} : (!fir.ref<!fir.array<10x10x10xf64>>, !fir.shape<3>) -> (!fir.ref<!fir.array<10x10x10xf64>>, !fir.ref<!fir.array<10x10x10xf64>>)
+! CHECK: cuf.data_transfer %{{.*}} to %[[D1_DECL]]#0 {transfer_kind = #cuf.cuda_transfer<host_device>} : f64, !fir.ref<!fir.array<10x10x10xf64>>