[flang-commits] [flang] [flang][OpenMP] Make static duration variables default to shared DSA (PR #142783)

[Kajetan Puchalski via flang-commits]

https://github.com/mrkajetanp updated https://github.com/llvm/llvm-project/pull/142783

>From 84f9a709a70e0bcc99380091ed5956f82145d43c Mon Sep 17 00:00:00 2001
From: Kajetan Puchalski <kajetan.puchalski at arm.com>
Date: Wed, 4 Jun 2025 11:36:02 +0000
Subject: [PATCH 1/2] [flang][OpenMP] Make static duration variables default to
 shared DSA

According to the OpenMP standard, variables with static storage duration
are predetermined as shared.
Add a check when creating implicit symbols for OpenMP to fix them
erroneously getting set to firstprivate.

Fixes llvm#140732.

Signed-off-by: Kajetan Puchalski <kajetan.puchalski at arm.com>
---
 flang/lib/Semantics/resolve-directives.cpp   |  5 ++++-
 flang/test/Semantics/OpenMP/implicit-dsa.f90 | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index ec385b7baf8bd..d1495e7b3b7f2 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -2310,6 +2310,8 @@ void OmpAttributeVisitor::CreateImplicitSymbols(const Symbol *symbol) {
     bool targetDir = llvm::omp::allTargetSet.test(dirContext.directive);
     bool parallelDir = llvm::omp::allParallelSet.test(dirContext.directive);
     bool teamsDir = llvm::omp::allTeamsSet.test(dirContext.directive);
+    bool isStaticStorageDuration =
+        symbol->flags().test(Symbol::Flag::InDataStmt);
 
     if (dsa.any()) {
       if (parallelDir || taskGenDir || teamsDir) {
@@ -2367,7 +2369,8 @@ void OmpAttributeVisitor::CreateImplicitSymbols(const Symbol *symbol) {
       dsa = prevDSA;
     } else if (taskGenDir) {
       // TODO 5) dummy arg in orphaned taskgen construct -> firstprivate
-      if (prevDSA.test(Symbol::Flag::OmpShared)) {
+      // variables with static storage duration are predetermined as shared
+      if (prevDSA.test(Symbol::Flag::OmpShared) || isStaticStorageDuration) {
         // 6) shared in enclosing context -> shared
         dsa = {Symbol::Flag::OmpShared};
         makeSymbol(dsa);
diff --git a/flang/test/Semantics/OpenMP/implicit-dsa.f90 b/flang/test/Semantics/OpenMP/implicit-dsa.f90
index 7e38435274b7b..9e48dd2a83257 100644
--- a/flang/test/Semantics/OpenMP/implicit-dsa.f90
+++ b/flang/test/Semantics/OpenMP/implicit-dsa.f90
@@ -169,3 +169,23 @@ subroutine implicit_dsa_test8
     end do
   !$omp end task
 end subroutine
+
+! Test static storage duration variables default to shared DSA
+!DEF: /implicit_dsa_test9_mod Module
+module implicit_dsa_test9_mod
+ !DEF: /implicit_dsa_test9_mod/tm3a PUBLIC (InDataStmt) ObjectEntity COMPLEX(4)
+  complex tm3a/(0,0)/
+contains
+ !DEF: /implicit_dsa_test9_mod/implict_dsa_test9 PUBLIC (Subroutine) Subprogram
+  subroutine implict_dsa_test9
+    !$omp task
+      !$omp task
+        !DEF: /implicit_dsa_test9_mod/implict_dsa_test9/OtherConstruct1/OtherConstruct1/tm3a (OmpShared) HostAssoc COMPLEX(4)
+        tm3a = (1, 2)
+      !$omp end task
+    !$omp end task
+  !$omp taskwait
+  !REF: /implicit_dsa_test9_mod/tm3a
+  print *,tm3a
+  end subroutine
+end module

>From 0b40d021a14eab90bfa1f461d19b8df380faaee1 Mon Sep 17 00:00:00 2001
From: Kajetan Puchalski <kajetan.puchalski at arm.com>
Date: Thu, 5 Jun 2025 15:19:47 +0000
Subject: [PATCH 2/2] Refactor for better debug output, add data stmt test

---
 flang/lib/Semantics/resolve-directives.cpp   | 12 ++++++++----
 flang/test/Semantics/OpenMP/implicit-dsa.f90 | 18 +++++++++++++++++-
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index d1495e7b3b7f2..6deea0c0f8d26 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -2369,17 +2369,21 @@ void OmpAttributeVisitor::CreateImplicitSymbols(const Symbol *symbol) {
       dsa = prevDSA;
     } else if (taskGenDir) {
       // TODO 5) dummy arg in orphaned taskgen construct -> firstprivate
-      // variables with static storage duration are predetermined as shared
-      if (prevDSA.test(Symbol::Flag::OmpShared) || isStaticStorageDuration) {
+      if (prevDSA.test(Symbol::Flag::OmpShared)) {
         // 6) shared in enclosing context -> shared
         dsa = {Symbol::Flag::OmpShared};
         makeSymbol(dsa);
         PRINT_IMPLICIT_RULE("6) taskgen: shared");
+      } else if (isStaticStorageDuration) {
+        // 7) variables with static storage duration are predetermined as shared
+        dsa = {Symbol::Flag::OmpShared};
+        makeSymbol(dsa);
+        PRINT_IMPLICIT_RULE("7) taskgen: shared (static storage duration)");
       } else {
-        // 7) firstprivate
+        // 8) firstprivate
         dsa = {Symbol::Flag::OmpFirstPrivate};
         makeSymbol(dsa)->set(Symbol::Flag::OmpImplicit);
-        PRINT_IMPLICIT_RULE("7) taskgen: firstprivate");
+        PRINT_IMPLICIT_RULE("8) taskgen: firstprivate");
       }
     }
     prevDSA = dsa;
diff --git a/flang/test/Semantics/OpenMP/implicit-dsa.f90 b/flang/test/Semantics/OpenMP/implicit-dsa.f90
index 9e48dd2a83257..6e10ba948007a 100644
--- a/flang/test/Semantics/OpenMP/implicit-dsa.f90
+++ b/flang/test/Semantics/OpenMP/implicit-dsa.f90
@@ -170,7 +170,7 @@ subroutine implicit_dsa_test8
   !$omp end task
 end subroutine
 
-! Test static storage duration variables default to shared DSA
+! Test variables defined in modules default to shared DSA
 !DEF: /implicit_dsa_test9_mod Module
 module implicit_dsa_test9_mod
  !DEF: /implicit_dsa_test9_mod/tm3a PUBLIC (InDataStmt) ObjectEntity COMPLEX(4)
@@ -189,3 +189,19 @@ subroutine implict_dsa_test9
   print *,tm3a
   end subroutine
 end module
+
+! Test variables in data statement default to shared DSA
+!DEF: /implicit_dsa_test10 (Subroutine) Subprogram
+subroutine implicit_dsa_test10
+ !DEF: /implicit_dsa_test10/tm3a (Implicit, InDataStmt) ObjectEntity REAL(4)
+data tm3a /(0, 2)/
+!$omp task
+  !$omp task
+ !DEF: /implicit_dsa_test10/OtherConstruct1/OtherConstruct1/tm3a (OmpShared) HostAssoc REAL(4)
+    tm3a = (1, 2)
+  !$omp end task
+!$omp end task
+!$omp taskwait
+ !REF: /implicit_dsa_test10/tm3a
+print *,tm3a
+end subroutine