[flang-commits] [flang] 0a41c8e - [flang][cuda] Avoid generating cuf.data_transfer in OpenACC region (#106435)

[via flang-commits]

Author: Valentin Clement (バレンタイン クレメン)
Date: 2024-08-29T11:27:42-07:00
New Revision: 0a41c8e7a050c837c609cbcbc8342024701cd14b

URL: https://github.com/llvm/llvm-project/commit/0a41c8e7a050c837c609cbcbc8342024701cd14b
DIFF: https://github.com/llvm/llvm-project/commit/0a41c8e7a050c837c609cbcbc8342024701cd14b.diff

LOG: [flang][cuda] Avoid generating cuf.data_transfer in OpenACC region (#106435)

`cuf.data_transfer` will be converted to runtime calls to cuda runtime
api and these are not supported in device code. assignment in OpenACC
region will be handled by the OpenACC code gen so we avoid to generate
data transfer on them.

Added: 
    

Modified: 
    flang/lib/Lower/Bridge.cpp
    flang/test/Lower/CUDA/cuda-data-transfer.cuf

Removed: 
    


################################################################################
diff  --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
index c48daba8cf7fab..078e17bea55859 100644
--- a/flang/lib/Lower/Bridge.cpp
+++ b/flang/lib/Lower/Bridge.cpp
@@ -4380,9 +4380,14 @@ class FirConverter : public Fortran::lower::AbstractConverter {
   // Check if the insertion point is currently in a device context. HostDevice
   // subprogram are not considered fully device context so it will return false
   // for it.
-  static bool isDeviceContext(fir::FirOpBuilder &builder) {
+  // If the insertion point is inside an OpenACC region op, it is considered
+  // device context.
+  static bool isCudaDeviceContext(fir::FirOpBuilder &builder) {
     if (builder.getRegion().getParentOfType<cuf::KernelOp>())
       return true;
+    if (builder.getRegion()
+            .getParentOfType<mlir::acc::ComputeRegionOpInterface>())
+      return true;
     if (auto funcOp =
             builder.getRegion().getParentOfType<mlir::func::FuncOp>()) {
       if (auto cudaProcAttr =
@@ -4401,7 +4406,8 @@ class FirConverter : public Fortran::lower::AbstractConverter {
     mlir::Location loc = getCurrentLocation();
     fir::FirOpBuilder &builder = getFirOpBuilder();
 
-    bool isInDeviceContext = isDeviceContext(builder);
+    bool isInDeviceContext = isCudaDeviceContext(builder);
+
     bool isCUDATransfer = (Fortran::evaluate::HasCUDADeviceAttrs(assign.lhs) ||
                            Fortran::evaluate::HasCUDADeviceAttrs(assign.rhs)) &&
                           !isInDeviceContext;

diff  --git a/flang/test/Lower/CUDA/cuda-data-transfer.cuf b/flang/test/Lower/CUDA/cuda-data-transfer.cuf
index 42b37fb89e4ce2..f189bf9b621082 100644
--- a/flang/test/Lower/CUDA/cuda-data-transfer.cuf
+++ b/flang/test/Lower/CUDA/cuda-data-transfer.cuf
@@ -1,4 +1,4 @@
-! RUN: bbc -emit-hlfir -fcuda %s -o - | FileCheck %s
+! RUN: bbc -emit-hlfir -fopenacc -fcuda %s -o - | FileCheck %s
 
 ! Test CUDA Fortran data transfer using assignment statements.
 
@@ -290,3 +290,45 @@ end subroutine
 ! CHECK: %[[SHAPE:.*]] = fir.shape %{{.*}} : (index) -> !fir.shape<1>
 ! CHECK: %[[AHOST:.*]]:2 = hlfir.declare %[[ARG1]](%{{.*}}) dummy_scope %{{.*}} {uniq_name = "_QFsub15Ea_host"} : (!fir.ref<!fir.array<?xf32>>, !fir.shape<1>, !fir.dscope) -> (!fir.box<!fir.array<?xf32>>, !fir.ref<!fir.array<?xf32>>)
 ! CHECK: cuf.data_transfer %[[AHOST]]#1 to %[[ADEV]]#1, %[[SHAPE]] : !fir.shape<1> {transfer_kind = #cuf.cuda_transfer<host_device>} : !fir.ref<!fir.array<?xf32>>, !fir.ref<!fir.array<?xf32>>
+
+! Check that cuf.data_transfer are not generated within OpenACC region
+subroutine sub16()
+  integer, parameter :: n = 10
+  real, device :: adev(n)
+  real :: ahost(n)
+  real, managed :: b
+  integer :: i
+
+  adev = ahost
+  !$acc parallel loop deviceptr(adev) 
+  do i = 1, n
+    adev(i) = adev(i) + b
+  enddo
+
+  !$acc kernels deviceptr(adev) 
+  do i = 1, n
+    adev(i) = adev(i) + b
+  enddo
+  !$acc end kernels
+
+
+  !$acc serial deviceptr(adev) 
+  do i = 1, n
+    adev(i) = adev(i) + b
+  enddo
+  !$acc end serial
+end subroutine
+
+! CHECK-LABEL: func.func @_QPsub16()
+! CHECK: cuf.data_transfer
+! CHECK: acc.parallel
+! CHECK-NOT: cuf.data_transfer
+! CHECK: hlfir.assign
+
+! CHECK: acc.kernels
+! CHECK-NOT: cuf.data_transfer
+! CHECK: hlfir.assign
+
+! CHECK: acc.serial
+! CHECK-NOT: cuf.data_transfer
+! CHECK: hlfir.assign