[flang-commits] [flang] [flang][cuda] Apply implicit managed attribute to pointer variables under -gpu=mem:managed (PR #204634)

[Zhen Wang via flang-commits]

https://github.com/wangzpgi updated https://github.com/llvm/llvm-project/pull/204634

>From 4005fe8fb7899fc02584301d0a8597c30926da77 Mon Sep 17 00:00:00 2001
From: Zhen Wang <zhenw at nvidia.com>
Date: Wed, 17 Jun 2026 16:52:48 -0700
Subject: [PATCH 1/2] Apply implicit managed attribute to pointers under
 -gpu=mem:managed

---
 flang/lib/Semantics/resolve-names.cpp      | 12 +++++++-----
 flang/test/Lower/CUDA/cuda-gpu-managed.cuf | 13 ++++++-------
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index 6d2d0bf24b194..cee230f38499a 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -10397,10 +10397,11 @@ void ResolveNamesVisitor::FinishSpecificationPart(
     }
 
     if (auto *object{symbol.detailsIf<ObjectEntityDetails>()}) {
-      if (IsAllocatable(symbol) && !object->cudaDataAttr()) {
-        // Implicitly treat allocatable arrays as managed when feature is
-        // enabled. This is done after all explicit CUDA attributes have been
-        // processed. Only applies when CUDA Fortran is enabled; otherwise
+      if ((IsAllocatable(symbol) || IsPointer(symbol)) &&
+          !object->cudaDataAttr()) {
+        // Implicitly treat allocatable/pointer arrays as managed when feature
+        // is enabled. This is done after all explicit CUDA attributes have
+        // been processed. Only applies when CUDA Fortran is enabled; otherwise
         // -gpu=mem:managed on a non-CUDA-Fortran translation unit (e.g. pure
         // OpenACC) would incorrectly route every allocatable through the CUDA
         // Fortran managed descriptor pipeline.
@@ -10411,7 +10412,8 @@ void ResolveNamesVisitor::FinishSpecificationPart(
           object->set_cudaDataAttr(common::CUDADataAttr::Managed);
         // Implicitly treat allocatable arrays as pinned when feature is
         // enabled.
-        else if (context().languageFeatures().IsEnabled(
+        else if (IsAllocatable(symbol) &&
+                 context().languageFeatures().IsEnabled(
                      common::LanguageFeature::CudaPinned))
           object->set_cudaDataAttr(common::CUDADataAttr::Pinned);
       }
diff --git a/flang/test/Lower/CUDA/cuda-gpu-managed.cuf b/flang/test/Lower/CUDA/cuda-gpu-managed.cuf
index a9ae310978e19..e9b2df1d71ed5 100644
--- a/flang/test/Lower/CUDA/cuda-gpu-managed.cuf
+++ b/flang/test/Lower/CUDA/cuda-gpu-managed.cuf
@@ -65,20 +65,19 @@ end subroutine
 ! CHECK: %[[BOX_DECL:.*]]:2 = hlfir.declare %[[BOX]] {data_attr = #cuf.cuda<managed>, fortran_attrs = #fir.var_attrs<allocatable>, uniq_name = "_QFtest_explicit_managedEm"}
 
 ! -----------------------------------------------------------------------------
-! Test 5: Pointer variables are NOT affected by -gpu=managed
+! Test 5: Pointer variables are also implicitly managed with -gpu=managed
 ! -----------------------------------------------------------------------------
-subroutine test_pointer_not_managed()
+subroutine test_pointer_managed()
   real, pointer :: ptr(:)
   allocate(ptr(100))
   ptr = 1.0
   deallocate(ptr)
 end subroutine
 
-! CHECK-LABEL: func.func @_QPtest_pointer_not_managed()
-! CHECK: %[[BOX:.*]] = fir.alloca !fir.box<!fir.ptr<!fir.array<?xf32>>> {bindc_name = "ptr", uniq_name = "_QFtest_pointer_not_managedEptr"}
-! CHECK-NOT: data_attr = #cuf.cuda<managed>
-! CHECK: %[[BOX_DECL:.*]]:2 = hlfir.declare %[[BOX]] {fortran_attrs = #fir.var_attrs<pointer>, uniq_name = "_QFtest_pointer_not_managedEptr"}
-! CHECK: fir.call @_FortranAPointerAllocate
+! CHECK-LABEL: func.func @_QPtest_pointer_managed()
+! CHECK: %[[BOX:.*]] = cuf.alloc !fir.box<!fir.ptr<!fir.array<?xf32>>> {bindc_name = "ptr", data_attr = #cuf.cuda<managed>, uniq_name = "_QFtest_pointer_managedEptr"}
+! CHECK: %[[BOX_DECL:.*]]:2 = hlfir.declare %[[BOX]] {data_attr = #cuf.cuda<managed>, fortran_attrs = #fir.var_attrs<pointer>, uniq_name = "_QFtest_pointer_managedEptr"}
+! CHECK: cuf.allocate %[[BOX_DECL]]#0 : {{.*}} {data_attr = #cuf.cuda<managed>, pointer}
 
 ! -----------------------------------------------------------------------------
 ! Test 6: Multiple allocatables - mix of implicit and explicit

>From 8dd038c8826aa65e02dbd4e9fc9ddd5663836c2c Mon Sep 17 00:00:00 2001
From: Zhen Wang <zhenw at nvidia.com>
Date: Thu, 18 Jun 2026 10:00:09 -0700
Subject: [PATCH 2/2] format

---
 flang/lib/Semantics/resolve-names.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index cee230f38499a..c6800e15be9dc 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -10413,8 +10413,8 @@ void ResolveNamesVisitor::FinishSpecificationPart(
         // Implicitly treat allocatable arrays as pinned when feature is
         // enabled.
         else if (IsAllocatable(symbol) &&
-                 context().languageFeatures().IsEnabled(
-                     common::LanguageFeature::CudaPinned))
+            context().languageFeatures().IsEnabled(
+                common::LanguageFeature::CudaPinned))
           object->set_cudaDataAttr(common::CUDADataAttr::Pinned);
       }
     }