[flang-commits] [flang] [Flang][OpenMP] Avoid default none errors for seq loop indices in par… (PR #76258)

[Kiran Chandramohan via flang-commits]

https://github.com/kiranchandramohan created https://github.com/llvm/llvm-project/pull/76258

…allel

>From 03e611d413cffa6ff7432a8a88db5d6901449f3c Mon Sep 17 00:00:00 2001
From: Kiran Chandramohan <kiran.chandramohan at arm.com>
Date: Fri, 22 Dec 2023 18:35:00 +0000
Subject: [PATCH] [Flang][OpenMP] Avoid default none errors for seq loop
 indices in parallel

---
 flang/lib/Semantics/resolve-directives.cpp |  6 +++++-
 flang/test/Semantics/OpenMP/resolve05.f90  | 13 +++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index da6c865ad56a3b..6e782204e6368c 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -1910,7 +1910,11 @@ void OmpAttributeVisitor::Post(const parser::Name &name) {
       if (Symbol * found{currScope().FindSymbol(name.source)}) {
         if (symbol != found) {
           name.symbol = found; // adjust the symbol within region
-        } else if (GetContext().defaultDSA == Symbol::Flag::OmpNone) {
+        } else if (GetContext().defaultDSA == Symbol::Flag::OmpNone &&
+            // Exclude indices of sequential loops that are privatised in
+            // the scope of the parallel region, and not in this scope.
+            // TODO: check whether this should be caught in IsObjectWithDSA
+            !symbol->test(Symbol::Flag::OmpPrivate)) {
           context_.Say(name.source,
               "The DEFAULT(NONE) clause requires that '%s' must be listed in "
               "a data-sharing attribute clause"_err_en_US,
diff --git a/flang/test/Semantics/OpenMP/resolve05.f90 b/flang/test/Semantics/OpenMP/resolve05.f90
index 00f4860302183d..c4cebb48ac5c2b 100644
--- a/flang/test/Semantics/OpenMP/resolve05.f90
+++ b/flang/test/Semantics/OpenMP/resolve05.f90
@@ -17,7 +17,20 @@ subroutine default_none()
   !$omp end parallel
 end subroutine default_none
 
+! Test that indices of sequential loops are privatised and hence do not error
+! for DEFAULT(NONE)
+subroutine default_none_seq_loop
+  integer :: i
+
+  !$omp parallel do default(none)
+  do i = 1, 10
+     do j = 1, 20
+    enddo
+  enddo
+end subroutine
+
 program mm
   call default_none()
+  call default_none_seq_loop()
   !TODO: private, firstprivate, shared
 end