[flang-commits] [flang] [flang][OpenMP] Parse ORDERED as standalone when DEPEND/DOACROSS is p… (PR #156693)
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Wed Sep 3 08:25:22 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-flang-semantics
Author: Krzysztof Parzyszek (kparzysz)
<details>
<summary>Changes</summary>
…resent
The OpenMP spec 4.5-5.1 defines ORDERED as standalone when a DEPEND clause is present (with either SOURCE or SINK as argument). The OpenMP spec 5.2+ defines ORDERED as standalone when a DOACROSS clause is present.
---
Full diff: https://github.com/llvm/llvm-project/pull/156693.diff
6 Files Affected:
- (modified) flang/lib/Parser/openmp-parsers.cpp (+16-13)
- (modified) flang/lib/Semantics/check-omp-structure.cpp (+10-2)
- (modified) flang/test/Parser/OpenMP/fail-construct1.f90 (+2-2)
- (modified) flang/test/Parser/OpenMP/ordered-block-vs-standalone.f90 (+2-2)
- (modified) flang/test/Semantics/OpenMP/missing-end-directive.f90 (+4-4)
- (modified) flang/test/Semantics/OpenMP/ordered01.f90 (+2-15)
``````````diff
diff --git a/flang/lib/Parser/openmp-parsers.cpp b/flang/lib/Parser/openmp-parsers.cpp
index cc4e59d318bbe..b8913d94da1ac 100644
--- a/flang/lib/Parser/openmp-parsers.cpp
+++ b/flang/lib/Parser/openmp-parsers.cpp
@@ -1281,6 +1281,16 @@ static bool IsFortranBlockConstruct(const ExecutionPartConstruct &epc) {
}
}
+static bool IsStandaloneOrdered(const OmpDirectiveSpecification &dirSpec) {
+ // An ORDERED construct is standalone if it has DOACROSS or DEPEND clause.
+ return dirSpec.DirId() == llvm::omp::Directive::OMPD_ordered &&
+ llvm::any_of(dirSpec.Clauses().v, [](const OmpClause &clause) {
+ llvm::omp::Clause id{clause.Id()};
+ return id == llvm::omp::Clause::OMPC_depend ||
+ id == llvm::omp::Clause::OMPC_doacross;
+ });
+}
+
struct StrictlyStructuredBlockParser {
using resultType = Block;
@@ -1475,6 +1485,9 @@ struct OmpBlockConstructParser {
std::optional<resultType> Parse(ParseState &state) const {
if (auto &&begin{OmpBeginDirectiveParser(dir_).Parse(state)}) {
+ if (IsStandaloneOrdered(*begin)) {
+ return std::nullopt;
+ }
if (auto &&body{attempt(StrictlyStructuredBlockParser{}).Parse(state)}) {
// Try strictly-structured block with an optional end-directive
auto end{maybe(OmpEndDirectiveParser{dir_}).Parse(state)};
@@ -1486,17 +1499,6 @@ struct OmpBlockConstructParser {
attempt(LooselyStructuredBlockParser{}).Parse(state)}) {
// Try loosely-structured block with a mandatory end-directive.
auto end{maybe(OmpEndDirectiveParser{dir_}).Parse(state)};
- // Dereference outer optional (maybe() always succeeds) and look at the
- // inner optional.
- bool endPresent{end->has_value()};
-
- // ORDERED is special. We do need to return failure here so that the
- // standalone ORDERED construct can be distinguished from the block
- // associated construct.
- if (!endPresent && dir_ == llvm::omp::Directive::OMPD_ordered) {
- return std::nullopt;
- }
-
// Delay the error for a missing end-directive until semantics so that
// we have better control over the output.
return OmpBlockConstruct{OmpBeginDirective(std::move(*begin)),
@@ -1653,7 +1655,6 @@ TYPE_PARSER(sourced( //
static bool IsSimpleStandalone(const OmpDirectiveName &name) {
switch (name.v) {
case llvm::omp::Directive::OMPD_barrier:
- case llvm::omp::Directive::OMPD_ordered:
case llvm::omp::Directive::OMPD_scan:
case llvm::omp::Directive::OMPD_target_enter_data:
case llvm::omp::Directive::OMPD_target_exit_data:
@@ -1669,7 +1670,9 @@ static bool IsSimpleStandalone(const OmpDirectiveName &name) {
TYPE_PARSER(sourced( //
construct<OpenMPSimpleStandaloneConstruct>(
predicated(OmpDirectiveNameParser{}, IsSimpleStandalone) >=
- Parser<OmpDirectiveSpecification>{})))
+ Parser<OmpDirectiveSpecification>{}) ||
+ construct<OpenMPSimpleStandaloneConstruct>(
+ predicated(Parser<OmpDirectiveSpecification>{}, IsStandaloneOrdered))))
TYPE_PARSER(sourced( //
construct<OpenMPFlushConstruct>(
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index 2518b0fc45859..85d79a00d9aff 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -890,8 +890,16 @@ void OmpStructureChecker::Enter(const parser::OmpBlockConstruct &x) {
executableConstruct->u);
}};
if (!endSpec && !isStrictlyStructuredBlock(block)) {
- context_.Say(
- x.BeginDir().source, "Expected OpenMP end directive"_err_en_US);
+ llvm::omp::Directive dirId{beginSpec.DirId()};
+ auto &msg{context_.Say(beginSpec.source,
+ "Expected OpenMP END %s directive"_err_en_US,
+ parser::ToUpperCaseLetters(getDirectiveName(dirId)))};
+ // ORDERED has two variants, so be explicit about which variant we think
+ // this is.
+ if (dirId == llvm::omp::Directive::OMPD_ordered) {
+ msg.Attach(
+ beginSpec.source, "The ORDERED directive is block-associated"_en_US);
+ }
}
if (llvm::omp::allTargetSet.test(GetContext().directive)) {
diff --git a/flang/test/Parser/OpenMP/fail-construct1.f90 b/flang/test/Parser/OpenMP/fail-construct1.f90
index 9d1af903344d3..2aba50a81e7ea 100644
--- a/flang/test/Parser/OpenMP/fail-construct1.f90
+++ b/flang/test/Parser/OpenMP/fail-construct1.f90
@@ -1,5 +1,5 @@
! RUN: not %flang_fc1 -fsyntax-only -fopenmp %s 2>&1 | FileCheck %s
-!$omp parallel
-! CHECK: error: Expected OpenMP end directive
+!$omp parallel
+! CHECK: error: Expected OpenMP END PARALLEL directive
end
diff --git a/flang/test/Parser/OpenMP/ordered-block-vs-standalone.f90 b/flang/test/Parser/OpenMP/ordered-block-vs-standalone.f90
index b43e7feac14dc..58f1eae07ca6f 100644
--- a/flang/test/Parser/OpenMP/ordered-block-vs-standalone.f90
+++ b/flang/test/Parser/OpenMP/ordered-block-vs-standalone.f90
@@ -1,4 +1,4 @@
-! RUN: %flang_fc1 -fdebug-dump-parse-tree -fopenmp -fopenmp-version=45 %s | FileCheck %s
+! RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema -fopenmp -fopenmp-version=45 %s | FileCheck %s
! Check that standalone ORDERED is successfully distinguished form block associated ORDERED
@@ -12,7 +12,7 @@ subroutine standalone
! CHECK-NEXT: | OmpDirectiveName -> llvm::omp::Directive = ordered
! CHECK-NEXT: | OmpClauseList ->
! CHECK-NEXT: | Flags = None
- !$omp ordered
+ !$omp ordered depend(source)
x(i, j) = i + j
end do
end do
diff --git a/flang/test/Semantics/OpenMP/missing-end-directive.f90 b/flang/test/Semantics/OpenMP/missing-end-directive.f90
index 33481f9d650f4..6068740999ed6 100644
--- a/flang/test/Semantics/OpenMP/missing-end-directive.f90
+++ b/flang/test/Semantics/OpenMP/missing-end-directive.f90
@@ -2,15 +2,15 @@
! Test that we can diagnose missing end directives without an explosion of errors
-! ERROR: Expected OpenMP end directive
+! ERROR: Expected OpenMP END PARALLEL directive
!$omp parallel
-! ERROR: Expected OpenMP end directive
+! ERROR: Expected OpenMP END TASK directive
!$omp task
! ERROR: Expected OpenMP END SECTIONS directive
!$omp sections
-! ERROR: Expected OpenMP end directive
+! ERROR: Expected OpenMP END PARALLEL directive
!$omp parallel
-! ERROR: Expected OpenMP end directive
+! ERROR: Expected OpenMP END TASK directive
!$omp task
! ERROR: Expected OpenMP END SECTIONS directive
!$omp sections
diff --git a/flang/test/Semantics/OpenMP/ordered01.f90 b/flang/test/Semantics/OpenMP/ordered01.f90
index 12543acb2916b..75968a6f5ee45 100644
--- a/flang/test/Semantics/OpenMP/ordered01.f90
+++ b/flang/test/Semantics/OpenMP/ordered01.f90
@@ -52,27 +52,14 @@ program main
end do
!$omp end do
- !$omp do ordered(1)
- do i = 2, N
- !ERROR: DEPEND clauses are not allowed when ORDERED construct is a block construct with an ORDERED region
- !$omp ordered depend(source)
- arrayA(i) = foo(i)
- !$omp end ordered
- !ERROR: DEPEND clauses are not allowed when ORDERED construct is a block construct with an ORDERED region
- !$omp ordered depend(sink: i - 1)
- arrayB(i) = bar(arrayA(i), arrayB(i-1))
- !$omp end ordered
- end do
- !$omp end do
-
contains
subroutine work1()
- !ERROR: THREADS and SIMD clauses are not allowed when ORDERED construct is a standalone construct with no ORDERED region
+ !ERROR: Expected OpenMP END ORDERED directive
!$omp ordered simd
end subroutine work1
subroutine work2()
- !ERROR: THREADS and SIMD clauses are not allowed when ORDERED construct is a standalone construct with no ORDERED region
+ !ERROR: Expected OpenMP END ORDERED directive
!$omp ordered threads
end subroutine work2
``````````
</details>
https://github.com/llvm/llvm-project/pull/156693
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