[flang-commits] [flang] [Flang][OpenMP] : Compilation error involving Cray pointers and data sharing attributes (PR #82481)

[Kiran Kumar T P via flang-commits]

https://github.com/kiranktp created https://github.com/llvm/llvm-project/pull/82481

Issue description:
	When DEFAULT DSA is NONE, all data refs must be listed in one of the data sharing clause.
	But when a Cray pointer is listed in one of the data sharing clause, Cray pointee can be used in parallel region.
	This is valid as per standard.
	"Cray pointee's have the same data-sharing attribute as the storage with which their Cray pointers are associated."

Solution:
	Added a check to discard checking Cray pointee when DEFAULT DSA is NONE.

This patch has code changes and a test case.

>From 271fc050ee39f5278ceb0e7f673e64133c9aa091 Mon Sep 17 00:00:00 2001
From: Kiran Kumar T P <kirankumar.tp at amd.com>
Date: Wed, 21 Feb 2024 16:24:11 +0530
Subject: [PATCH] [Flang][OpenMP] : Compilation error involving Fortran
 pointers and data-sharing attributes

Issue description:
	When DEFAULT DSA is NONE, all data refs must be listed in one of the data sharing clause.
	But when a Cray pointer is listed in one of the data sharing clause, Cray pointee can be used in parallel region.
	This is valid as per standard.
	"Cray pointees have the same data-sharing attribute as the storage with which their Cray pointers are associated."

Solution:
	Added a check to discard checking Cray pointee when DEFAULT DSA is NONE.

This patch has code changes and a test case.
---
 flang/lib/Semantics/resolve-directives.cpp      |  4 +++-
 .../Semantics/OpenMP/cray-pointer-usage.f90     | 17 +++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 flang/test/Semantics/OpenMP/cray-pointer-usage.f90

diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index 4b6d083671bc92..fb336853ae0c2d 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -1995,7 +1995,9 @@ void OmpAttributeVisitor::Post(const parser::Name &name) {
             // 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)) {
+            !symbol->test(Symbol::Flag::OmpPrivate) &&
+            // If the symbol is a CrayPointee, It cannot appear in DSA clause
+            !symbol->test(Symbol::Flag::CrayPointee)) {
           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/cray-pointer-usage.f90 b/flang/test/Semantics/OpenMP/cray-pointer-usage.f90
new file mode 100644
index 00000000000000..5d3c7f085cc4d3
--- /dev/null
+++ b/flang/test/Semantics/OpenMP/cray-pointer-usage.f90
@@ -0,0 +1,17 @@
+!RUN: %python %S/../test_errors.py %s %flang -fopenmp
+subroutine test_crayptr
+  implicit none
+  integer :: I
+  real*8 var(*)
+  pointer(ivar,var)
+  real*8 pointee(8)
+
+  pointee(1) = 42.0
+  ivar = loc(pointee)
+
+  !$omp parallel num_threads(2) default(none) shared(ivar)
+    print *, var(1)
+  !$omp end parallel
+
+end subroutine test_crayptr
+