[flang-commits] [flang] [flang][OpenMP] Fix the creation of implicit symbols for locals (PR #233600)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-openmp

Author: Leandro Lupori (luporl)

<details>
<summary>Changes</summary>

When creating implicit symbols for variables that are declared in a
nested scope (e.g. in a BLOCK), the constructs that enclose the symbol
declaration must be skipped, since the symbol doesn't exist in them.

Fixes #<!-- -->230273

Assisted-By: Claude Opus 5.5


---
Full diff: https://github.com/llvm/llvm-project/pull/233600.diff


3 Files Affected:

- (modified) flang/lib/Semantics/resolve-directives.cpp (+5) 
- (modified) flang/test/Semantics/OpenMP/local-variables-3.f90 (+62) 
- (added) flang/test/Semantics/OpenMP/local-variables-4.f90 (+87) 


``````````diff
diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index c5a23e1adda395..5e10b02e39480b 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -2673,6 +2673,11 @@ void OmpAttributeVisitor::CreateImplicitSymbols(
     Symbol::Flags dsa;
 
     Scope &scope{context_.FindScope(dirContext.directiveSource)};
+    // Skip constructs that enclose the symbol declaration (e.g. in a nested
+    // BLOCK).
+    if (IsLocalInsideScope(symbol->GetUltimate(), scope)) {
+      continue;
+    }
 
     auto initSymbolDSA = [&](const Symbol *sym, Symbol::Flags &dsa) {
       auto it{scope.find(sym->name())};
diff --git a/flang/test/Semantics/OpenMP/local-variables-3.f90 b/flang/test/Semantics/OpenMP/local-variables-3.f90
index 20d44c39da1079..d843955f10154d 100644
--- a/flang/test/Semantics/OpenMP/local-variables-3.f90
+++ b/flang/test/Semantics/OpenMP/local-variables-3.f90
@@ -121,3 +121,65 @@ subroutine block04()
     !$omp end task
   end block
 end subroutine
+
+!CHECK-LABEL: !DEF: /block05 (Subroutine) Subprogram
+!CHECK: subroutine block05
+!CHECK: !$omp parallel default(private)
+!CHECK:  block
+!CHECK:   !DEF: /block05/OtherConstruct1/BlockConstruct1/cnt ObjectEntity INTEGER(4)
+!CHECK:   integer cnt
+!CHECK:   !REF: /block05/OtherConstruct1/BlockConstruct1/cnt
+!CHECK:   cnt = 0
+!CHECK: !$omp single
+!CHECK:   !REF: /block05/OtherConstruct1/BlockConstruct1/cnt
+!CHECK:   cnt = cnt+1
+!CHECK: !$omp end single
+!CHECK:  end block
+!CHECK: !$omp end parallel
+!CHECK: end subroutine
+
+subroutine block05()
+  !$omp parallel default(private)
+  block
+    integer :: cnt
+    cnt = 0
+    !$omp single
+    cnt = cnt + 1
+    !$omp end single
+  end block
+  !$omp end parallel
+end subroutine
+
+!CHECK-LABEL: !DEF: /block06 (Subroutine) Subprogram
+!CHECK: subroutine block06
+!CHECK: !$omp parallel default(private)
+!CHECK:  block
+!CHECK:   !DEF: /block06/OtherConstruct1/BlockConstruct1/auto ObjectEntity INTEGER(4)
+!CHECK:   integer auto
+!CHECK:   !DEF: /block06/OtherConstruct1/BlockConstruct1/s SAVE ObjectEntity INTEGER(4)
+!CHECK:   integer, save :: s
+!CHECK:   !REF: /block06/OtherConstruct1/BlockConstruct1/auto
+!CHECK:   auto = 1
+!CHECK: !$omp task
+!CHECK:   !DEF: /block06/OtherConstruct1/BlockConstruct1/OtherConstruct1/auto (OmpFirstPrivate, OmpImplicit) HostAssoc INTEGER(4)
+!CHECK:   auto = 2
+!CHECK:   !DEF: /block06/OtherConstruct1/BlockConstruct1/OtherConstruct1/s (OmpShared) HostAssoc INTEGER(4)
+!CHECK:   s = 3
+!CHECK: !$omp end task
+!CHECK:  end block
+!CHECK: !$omp end parallel
+!CHECK: end subroutine
+
+subroutine block06()
+  !$omp parallel default(private)
+  block
+    integer :: auto
+    integer, save :: s
+    auto = 1
+    !$omp task
+      auto = 2
+      s = 3
+    !$omp end task
+  end block
+  !$omp end parallel
+end subroutine
diff --git a/flang/test/Semantics/OpenMP/local-variables-4.f90 b/flang/test/Semantics/OpenMP/local-variables-4.f90
new file mode 100644
index 00000000000000..7a7653958f2310
--- /dev/null
+++ b/flang/test/Semantics/OpenMP/local-variables-4.f90
@@ -0,0 +1,87 @@
+!RUN: %python %S/../test_errors.py %s %flang_fc1 -fopenmp
+
+! A variable declared in a BLOCK inside an OpenMP construct has a predetermined
+! data-sharing attribute for that construct.
+
+subroutine s00
+  !$omp parallel default(none)
+  block
+    integer :: cnt
+    cnt = 0
+    !$omp single
+    cnt = cnt + 1
+    !$omp end single
+  end block
+  !$omp end parallel
+end
+
+subroutine s01
+  !$omp parallel default(none)
+  block
+    integer, save :: cnt
+    !$omp single
+    cnt = cnt + 1
+    !$omp end single
+  end block
+  !$omp end parallel
+end
+
+subroutine s02
+  !$omp parallel default(none)
+  block
+    integer :: v
+    v = 0
+    !$omp task firstprivate(v)
+    v = v + 1
+    !$omp end task
+  end block
+  !$omp end parallel
+end
+
+subroutine s03
+  integer :: x
+  !$omp parallel default(none)
+  block
+    !$omp single
+    !ERROR: The DEFAULT(NONE) clause requires that 'x' must be listed in a data-sharing attribute clause
+    x = 1
+    !$omp end single
+  end block
+  !$omp end parallel
+end
+
+subroutine s04
+  !$omp parallel default(none)
+  block
+    integer :: cnt
+    !$omp task default(none)
+    !ERROR: The DEFAULT(NONE) clause requires that 'cnt' must be listed in a data-sharing attribute clause
+    cnt = 1
+    !$omp end task
+  end block
+  !$omp end parallel
+end
+
+subroutine s05
+  !$omp parallel
+  block
+    integer :: v
+    !$omp single
+    v = 7
+    !$omp end single copyprivate(v)
+    print *, v
+  end block
+  !$omp end parallel
+end
+
+subroutine s06
+  !$omp parallel
+  block
+    integer, save :: s
+    !$omp single
+    s = 7
+    !ERROR: COPYPRIVATE variable 's' is not PRIVATE or THREADPRIVATE in outer context
+    !$omp end single copyprivate(s)
+  end block
+  !$omp end parallel
+end

``````````

</details>


https://github.com/llvm/llvm-project/pull/233600