[flang-commits] [flang] [flang][openacc][cuda] Recover acc routine bind info in CUDA Fortran module reads (PR #223595)

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

https://github.com/clementval updated https://github.com/llvm/llvm-project/pull/223595

>From d55d185dd0e50e8c3c330b7a01a447da8788494b Mon Sep 17 00:00:00 2001
From: Valentin Clement <clementval at gmail.com>
Date: Mon, 14 Sep 2026 20:43:57 -0700
Subject: [PATCH] [flang][acc] Recover acc routine bind info in CUDA Fortran
 module reads

---
 flang/lib/Semantics/mod-file.cpp              |  7 ++-
 flang/lib/Semantics/resolve-directives.cpp    |  8 +++-
 .../OpenACC/acc-routine-bind-cuda-modfile.cuf | 45 +++++++++++++++++++
 3 files changed, 58 insertions(+), 2 deletions(-)
 create mode 100644 flang/test/Lower/OpenACC/acc-routine-bind-cuda-modfile.cuf

diff --git a/flang/lib/Semantics/mod-file.cpp b/flang/lib/Semantics/mod-file.cpp
index edbca4a9015aa..e17bfb2ee3f32 100644
--- a/flang/lib/Semantics/mod-file.cpp
+++ b/flang/lib/Semantics/mod-file.cpp
@@ -1754,7 +1754,12 @@ Scope *ModFileReader::Read(SourceName name, std::optional<bool> isIntrinsic,
   parser::Options options;
   options.isModuleFile = true;
   options.features.Enable(common::LanguageFeature::BackslashEscapes);
-  if (context_.languageFeatures().IsEnabled(common::LanguageFeature::OpenACC)) {
+  // CUDA Fortran device code can call procedures whose device-side call target
+  // is described by an `acc routine bind(...)` directive in the module that
+  // declares them, so the sentinel must be recognized here even when this
+  // compilation itself was not given an OpenACC target.
+  if (context_.languageFeatures().IsEnabled(common::LanguageFeature::OpenACC) ||
+      context_.languageFeatures().IsEnabled(common::LanguageFeature::CUDA)) {
     options.features.Enable(common::LanguageFeature::OpenACC);
   }
   options.features.Enable(common::LanguageFeature::OpenMP);
diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index 143fe385768d7..f7a9e252d0d49 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -1058,7 +1058,13 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
 
 void ResolveAccParts(SemanticsContext &context, const parser::ProgramUnit &node,
     Scope *topScope) {
-  if (context.IsEnabled(common::LanguageFeature::OpenACC)) {
+  // A CUDA Fortran compilation that was not given an OpenACC target still has
+  // to resolve the directives recovered from module files, because they can
+  // describe the device-side call target of a procedure through
+  // `acc routine bind(...)`. The sentinel is not recognized in the main source
+  // in that case, so no user directive can reach this point.
+  if (context.IsEnabled(common::LanguageFeature::OpenACC) ||
+      context.IsEnabled(common::LanguageFeature::CUDA)) {
     AccAttributeVisitor{context, topScope}.Walk(node);
   }
 }
diff --git a/flang/test/Lower/OpenACC/acc-routine-bind-cuda-modfile.cuf b/flang/test/Lower/OpenACC/acc-routine-bind-cuda-modfile.cuf
new file mode 100644
index 0000000000000..87adadcefcdf8
--- /dev/null
+++ b/flang/test/Lower/OpenACC/acc-routine-bind-cuda-modfile.cuf
@@ -0,0 +1,45 @@
+! CUDA Fortran can consume `acc routine bind(...)` recovered from a module
+! file even when this translation unit is compiled without -fopenacc.
+
+! RUN: split-file %s %t
+! RUN: bbc -fopenacc -fcuda -emit-hlfir %t/mod.cuf -o %t/mod.mlir --module=%t
+! RUN: bbc -fcuda -emit-hlfir %t/use.cuf -o - -I %t | FileCheck %s
+
+//--- mod.cuf
+module m
+  interface
+    attributes(host,device) function my_device_func(x) bind(c) result(res)
+      integer(4), value :: x
+      integer(4) :: res
+    end function
+  end interface
+
+  interface
+    attributes(host,device) subroutine my_device_sub(x, res) bind(c)
+      integer(4), value :: x
+      integer(4) :: res
+    end subroutine
+  end interface
+
+  !$acc routine(my_device_func) seq bind('__wrapper_my_device_func')
+  !$acc routine(my_device_sub) seq bind('__wrapper_my_device_sub')
+end module
+
+//--- use.cuf
+attributes(device) subroutine test
+  use m
+  implicit none
+  integer(4) :: a, b
+
+  b = my_device_func(a)
+  call my_device_sub(a, b)
+end subroutine test
+
+! CHECK-DAG: acc.routine @[[ROUT_FUNC:.*]] func(@my_device_func) bind("__wrapper_my_device_func") seq
+! CHECK-DAG: acc.routine @[[ROUT_SUB:.*]] func(@my_device_sub) bind("__wrapper_my_device_sub") seq
+! CHECK-LABEL: func.func @_QPtest()
+! CHECK-SAME: attributes {cuf.proc_attr = #cuf.cuda_proc<device>}
+! CHECK: fir.call @my_device_func(
+! CHECK: fir.call @my_device_sub(
+! CHECK: func.func private @my_device_func{{.*}}acc.routine_info = #acc.routine_info<[@[[ROUT_FUNC]]]>
+! CHECK: func.func private @my_device_sub{{.*}}acc.routine_info = #acc.routine_info<[@[[ROUT_SUB]]]>