[flang-commits] [flang] [flang][OpenMP] Remember original range in ExecutionPartIterator (PR #185290)
Krzysztof Parzyszek via flang-commits
flang-commits at lists.llvm.org
Mon Mar 9 05:32:01 PDT 2026
https://github.com/kparzysz updated https://github.com/llvm/llvm-project/pull/185290
>From 2d7d763b4cb55c3112454d5ad0022048125bc713 Mon Sep 17 00:00:00 2001
From: Krzysztof Parzyszek <Krzysztof.Parzyszek at amd.com>
Date: Thu, 19 Feb 2026 13:16:34 -0600
Subject: [PATCH 1/2] [flang][OpenMP] Import ExecutionPartIterator et al into
semantics::omp, NFC
---
flang/include/flang/Semantics/openmp-utils.h | 13 +++++++++++++
flang/lib/Semantics/check-omp-loop.cpp | 3 ---
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/flang/include/flang/Semantics/openmp-utils.h b/flang/include/flang/Semantics/openmp-utils.h
index 90fd36708de0e..221e4cb23eada 100644
--- a/flang/include/flang/Semantics/openmp-utils.h
+++ b/flang/include/flang/Semantics/openmp-utils.h
@@ -27,6 +27,14 @@
#include <type_traits>
#include <utility>
+namespace Fortran::parser::omp {
+struct ExecutionPartIterator;
+struct LoopNestIterator;
+template <typename T> struct ExecutionPartRange;
+using BlockRange = ExecutionPartRange<ExecutionPartIterator>;
+using LoopRange = ExecutionPartRange<LoopNestIterator>;
+} // namespace Fortran::parser::omp
+
namespace Fortran::semantics {
class Scope;
class SemanticsContext;
@@ -34,6 +42,11 @@ class Symbol;
// Add this namespace to avoid potential conflicts
namespace omp {
+using Fortran::parser::omp::ExecutionPartIterator;
+using Fortran::parser::omp::LoopNestIterator;
+using Fortran::parser::omp::BlockRange;
+using Fortran::parser::omp::LoopRange;
+
template <typename T, typename U = std::remove_const_t<T>> U AsRvalue(T &t) {
return U(t);
}
diff --git a/flang/lib/Semantics/check-omp-loop.cpp b/flang/lib/Semantics/check-omp-loop.cpp
index f81bde981594d..e13ea820c7ef6 100644
--- a/flang/lib/Semantics/check-omp-loop.cpp
+++ b/flang/lib/Semantics/check-omp-loop.cpp
@@ -334,7 +334,6 @@ static std::optional<size_t> CountGeneratedNests(const parser::Block &block) {
// messages about a potentially incorrect loop count.
// In such cases reset the count to nullopt. Once it becomes nullopt,
// keep it that way.
- using LoopRange = parser::omp::LoopRange;
std::optional<size_t> numLoops{0};
for (auto &epc : LoopRange(block, LoopRange::Step::Over)) {
if (auto genCount{CountGeneratedNests(epc)}) {
@@ -371,7 +370,6 @@ void OmpStructureChecker::CheckNestedConstruct(
// Check constructs contained in the body of the loop construct.
auto &body{std::get<parser::Block>(x.t)};
- using BlockRange = parser::omp::BlockRange;
for (auto &stmt : BlockRange(body, BlockRange::Step::Over)) {
if (auto *dir{parser::Unwrap<parser::CompilerDirective>(stmt)}) {
context_.Say(dir->source,
@@ -495,7 +493,6 @@ void OmpStructureChecker::SetLoopInfo(const parser::OpenMPLoopConstruct &x) {
void OmpStructureChecker::CheckIterationVariableType(
const parser::OpenMPLoopConstruct &x) {
- using LoopRange = parser::omp::LoopRange;
auto &body{std::get<parser::Block>(x.t)};
for (auto &construct : LoopRange(body, LoopRange::Step::Into)) {
// 'construct' can also be OpenMPLoopConstruct
>From 77235406105e7e686f1ca19bbfb4956aeef9257e Mon Sep 17 00:00:00 2001
From: Krzysztof Parzyszek <Krzysztof.Parzyszek at amd.com>
Date: Wed, 18 Feb 2026 10:53:13 -0600
Subject: [PATCH 2/2] [flang][OpenMP] Remember original range in
ExecutionPartIterator
Storing the original range (instead of just the "remaining part")
will allow the iterator component to be reused.
---
flang/include/flang/Parser/openmp-utils.h | 25 ++++++++++++++++++-----
flang/lib/Parser/openmp-utils.cpp | 11 ++++------
2 files changed, 24 insertions(+), 12 deletions(-)
diff --git a/flang/include/flang/Parser/openmp-utils.h b/flang/include/flang/Parser/openmp-utils.h
index f23e52585d567..20754ad28d26d 100644
--- a/flang/include/flang/Parser/openmp-utils.h
+++ b/flang/include/flang/Parser/openmp-utils.h
@@ -296,14 +296,28 @@ struct ExecutionPartIterator {
using IteratorType = Block::const_iterator;
using IteratorRange = llvm::iterator_range<IteratorType>;
+ // An iterator range with a third iterator indicating a position inside
+ // the range.
+ struct IteratorGauge : public IteratorRange {
+ IteratorGauge(IteratorType b, IteratorType e)
+ : IteratorRange(b, e), at(b) {}
+ IteratorGauge(IteratorRange r) : IteratorRange(r), at(r.begin()) {}
+
+ bool atEnd() const { return at == end(); }
+ IteratorType at;
+ };
+
struct Construct {
Construct(IteratorType b, IteratorType e, const ExecutionPartConstruct *c)
- : range(b, e), owner(c) {}
+ : location(b, e), owner(c) {}
template <typename R>
Construct(const R &r, const ExecutionPartConstruct *c)
- : range(r), owner(c) {}
+ : location(r), owner(c) {}
Construct(const Construct &c) = default;
- IteratorRange range;
+ // The original range of the construct with the current position in it.
+ // The location.at is the construct currently being pointed at, or
+ // stepped into.
+ IteratorGauge location;
const ExecutionPartConstruct *owner;
};
@@ -332,6 +346,7 @@ struct ExecutionPartIterator {
bool valid() const { return !stack_.empty(); }
+ const std::vector<Construct> &stack() const { return stack_; }
decltype(auto) operator*() const { return *at(); }
bool operator==(const ExecutionPartIterator &other) const {
if (valid() != other.valid()) {
@@ -339,7 +354,7 @@ struct ExecutionPartIterator {
}
// Invalid iterators are considered equal.
return !valid() ||
- stack_.back().range.begin() == other.stack_.back().range.begin();
+ stack_.back().location.at == other.stack_.back().location.at;
}
bool operator!=(const ExecutionPartIterator &other) const {
return !(*this == other);
@@ -368,7 +383,7 @@ struct ExecutionPartIterator {
using iterator_category = std::forward_iterator_tag;
private:
- IteratorType at() const { return stack_.back().range.begin(); };
+ IteratorType at() const { return stack_.back().location.at; };
// If the iterator is not at a legal location, keep advancing it until
// it lands at a legal location or becomes invalid.
diff --git a/flang/lib/Parser/openmp-utils.cpp b/flang/lib/Parser/openmp-utils.cpp
index 6d4326af78344..f83a658104396 100644
--- a/flang/lib/Parser/openmp-utils.cpp
+++ b/flang/lib/Parser/openmp-utils.cpp
@@ -243,8 +243,7 @@ void ExecutionPartIterator::step() {
} else if (auto *loop{GetDoConstruct(*where)}) {
stack_.emplace_back(std::get<Block>(loop->t), &*where);
} else {
- stack_.back().range =
- IteratorRange(std::next(where), stack_.back().range.end());
+ ++stack_.back().location.at;
}
adjust();
}
@@ -254,8 +253,7 @@ void ExecutionPartIterator::next() {
// Advance the iterator to the next legal position. If the current
// position is a DO-loop or a loop construct, step over it.
if (valid()) {
- stack_.back().range =
- IteratorRange(std::next(at()), stack_.back().range.end());
+ ++stack_.back().location.at;
adjust();
}
}
@@ -264,11 +262,10 @@ void ExecutionPartIterator::adjust() {
// If the iterator is not at a legal location, keep advancing it until
// it lands at a legal location or becomes invalid.
while (valid()) {
- if (stack_.back().range.empty()) {
+ if (stack_.back().location.atEnd()) {
stack_.pop_back();
if (valid()) {
- stack_.back().range =
- IteratorRange(std::next(at()), stack_.back().range.end());
+ ++stack_.back().location.at;
}
} else if (auto *block{GetFortranBlockConstruct(*at())}) {
stack_.emplace_back(std::get<Block>(block->t), &*at());
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