[flang-commits] [flang] [Flang] - Enhance testing for strictly-nested teams in target regions. (PR #168437)

[Pranav Bhandarkar via flang-commits]

https://github.com/bhandarkar-pranav updated https://github.com/llvm/llvm-project/pull/168437

>From fb029d24c77130945d68ba4247121e397f3e81c6 Mon Sep 17 00:00:00 2001
From: Pranav Bhandarkar <pranav.bhandarkar at amd.com>
Date: Mon, 17 Nov 2025 14:42:29 -0600
Subject: [PATCH 1/2] [Flang] - Enhance testing for strictly-nested teams in
 target regions.

This patch enhances the semantics test for checking that teams directives
are strictly nested inside target directives.
---
 flang/lib/Semantics/check-omp-loop.cpp        |  9 ++++++++
 flang/lib/Semantics/check-omp-structure.cpp   |  7 ++++++
 .../Semantics/OpenMP/target-teams-nesting.f90 | 22 +++++++++++++++++++
 3 files changed, 38 insertions(+)
 create mode 100644 flang/test/Semantics/OpenMP/target-teams-nesting.f90

diff --git a/flang/lib/Semantics/check-omp-loop.cpp b/flang/lib/Semantics/check-omp-loop.cpp
index aaaa2d6e78280..09005e3076d03 100644
--- a/flang/lib/Semantics/check-omp-loop.cpp
+++ b/flang/lib/Semantics/check-omp-loop.cpp
@@ -262,6 +262,15 @@ void OmpStructureChecker::Enter(const parser::OpenMPLoopConstruct &x) {
     EnterDirectiveNest(SIMDNest);
   }
 
+  if (CurrentDirectiveIsNested() &&
+      llvm::omp::allTeamsSet.test(GetContext().directive) &&
+      GetContextParent().directive == llvm::omp::Directive::OMPD_target &&
+      !GetDirectiveNest(TargetBlockOnlyTeams)) {
+    context_.Say(GetContextParent().directiveSource,
+        "TARGET construct with nested TEAMS region contains statements or "
+        "directives outside of the TEAMS construct"_err_en_US);
+  }
+
   // Combined target loop constructs are target device constructs. Keep track of
   // whether any such construct has been visited to later check that REQUIRES
   // directives for target-related options don't appear after them.
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index 37b4404cc598f..472208949abad 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -5215,6 +5215,13 @@ bool OmpStructureChecker::CheckTargetBlockOnlyTeams(
         if (dirId == llvm::omp::Directive::OMPD_teams) {
           nestedTeams = true;
         }
+      } else if (const auto *ompLoopConstruct{
+                     std::get_if<parser::OpenMPLoopConstruct>(
+                         &ompConstruct->u)}) {
+        llvm::omp::Directive dirId{ompLoopConstruct->BeginDir().DirId()};
+        if (llvm::omp::allTeamsSet.test(dirId)) {
+          nestedTeams = true;
+        }
       }
     }
 
diff --git a/flang/test/Semantics/OpenMP/target-teams-nesting.f90 b/flang/test/Semantics/OpenMP/target-teams-nesting.f90
new file mode 100644
index 0000000000000..59786d4f9e397
--- /dev/null
+++ b/flang/test/Semantics/OpenMP/target-teams-nesting.f90
@@ -0,0 +1,22 @@
+! RUN: %python %S/../test_errors.py %s %flang_fc1 -fopenmp
+
+program main
+  implicit none
+  integer, parameter :: n = 100
+  integer, parameter :: expected = n+2
+  integer :: i
+  integer :: counter
+
+  counter = 0
+  !ERROR: TARGET construct with nested TEAMS region contains statements or directives outside of the TEAMS construct
+  !$omp target map(tofrom:counter)
+  counter = counter+1
+  !$omp teams distribute reduction(+:counter)
+  do i=1, n
+     counter = counter+1
+  end do
+  counter = counter+1
+  !$omp end target
+
+  print '("Result: "I0)', counter
+ end program

>From 5c76adacac31975deb8552af963dba67b584fb01 Mon Sep 17 00:00:00 2001
From: Pranav Bhandarkar <pranav.bhandarkar at amd.com>
Date: Mon, 17 Nov 2025 14:52:18 -0600
Subject: [PATCH 2/2] use topTeamsSet not allTeamsSet

---
 flang/lib/Semantics/check-omp-loop.cpp      | 2 +-
 flang/lib/Semantics/check-omp-structure.cpp | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/flang/lib/Semantics/check-omp-loop.cpp b/flang/lib/Semantics/check-omp-loop.cpp
index 09005e3076d03..1cdd17b3a5b81 100644
--- a/flang/lib/Semantics/check-omp-loop.cpp
+++ b/flang/lib/Semantics/check-omp-loop.cpp
@@ -263,7 +263,7 @@ void OmpStructureChecker::Enter(const parser::OpenMPLoopConstruct &x) {
   }
 
   if (CurrentDirectiveIsNested() &&
-      llvm::omp::allTeamsSet.test(GetContext().directive) &&
+      llvm::omp::topTeamsSet.test(GetContext().directive) &&
       GetContextParent().directive == llvm::omp::Directive::OMPD_target &&
       !GetDirectiveNest(TargetBlockOnlyTeams)) {
     context_.Say(GetContextParent().directiveSource,
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index 472208949abad..cd67178fe8bf9 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -5219,7 +5219,7 @@ bool OmpStructureChecker::CheckTargetBlockOnlyTeams(
                      std::get_if<parser::OpenMPLoopConstruct>(
                          &ompConstruct->u)}) {
         llvm::omp::Directive dirId{ompLoopConstruct->BeginDir().DirId()};
-        if (llvm::omp::allTeamsSet.test(dirId)) {
+        if (llvm::omp::topTeamsSet.test(dirId)) {
           nestedTeams = true;
         }
       }