Revert "[Flang] Add perfect-nest and rectangular-loop semantic tests (llvm#160283)"

breaks 463.swim build

This reverts commit ec91d6b.

Author: ronlieb

flang/lib/Semantics/resolve-directives.cpp

@@ -149,24 +149,7 @@ template <typename T> class DirectiveAttributeVisitor {
     dataSharingAttributeObjects_.clear();
   }
   bool HasDataSharingAttributeObject(const Symbol &);
-
-  /// Extract the iv and bounds of a DO loop:
-  /// 1. The loop index/induction variable
-  /// 2. The lower bound
-  /// 3. The upper bound
-  /// 4. The step/increment (or nullptr if not present)
-  ///
-  /// Each returned tuple value can be nullptr if not present. Diagnoses an
-  /// error if the the DO loop is a DO WHILE or DO CONCURRENT loop.
-  std::tuple<const parser::Name *, const parser::ScalarExpr *,
-      const parser::ScalarExpr *, const parser::ScalarExpr *>
-  GetLoopBounds(const parser::DoConstruct &);
-
-  /// Extract the loop index/induction variable from a DO loop. Diagnoses an
-  /// error if the the DO loop is a DO WHILE or DO CONCURRENT loop and returns
-  /// nullptr.
   const parser::Name *GetLoopIndex(const parser::DoConstruct &);
-
   const parser::DoConstruct *GetDoConstructIf(
       const parser::ExecutionPartConstruct &);
   Symbol *DeclareNewAccessEntity(const Symbol &, Symbol::Flag, Scope &);
@@ -970,13 +953,6 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
     privateDataSharingAttributeObjects_.clear();
   }
 
-  /// Check that loops in the loop nest are perfectly nested, as well that lower
-  /// bound, upper bound, and step expressions do not use the iv
-  /// of a surrounding loop of the associated loops nest.
-  /// We do not support non-perfectly nested loops not non-rectangular loops yet
-  /// (both introduced in OpenMP 5.0)
-  void CheckPerfectNestAndRectangularLoop(const parser::OpenMPLoopConstruct &x);
-
   // Predetermined DSA rules
   void PrivatizeAssociatedLoopIndexAndCheckLoopLevel(
       const parser::OpenMPLoopConstruct &);
@@ -1052,30 +1028,23 @@ bool DirectiveAttributeVisitor<T>::HasDataSharingAttributeObject(
 }
 
 template <typename T>
-std::tuple<const parser::Name *, const parser::ScalarExpr *,
-    const parser::ScalarExpr *, const parser::ScalarExpr *>
-DirectiveAttributeVisitor<T>::GetLoopBounds(const parser::DoConstruct &x) {
+const parser::Name *DirectiveAttributeVisitor<T>::GetLoopIndex(
+    const parser::DoConstruct &x) {
   using Bounds = parser::LoopControl::Bounds;
   if (x.GetLoopControl()) {
     if (const Bounds * b{std::get_if<Bounds>(&x.GetLoopControl()->u)}) {
-      auto &step = b->step;
-      return {&b->name.thing, &b->lower, &b->upper,
-          step.has_value() ? &step.value() : nullptr};
+      return &b->name.thing;
+    } else {
+      return nullptr;
     }
   } else {
     context_
         .Say(std::get<parser::Statement<parser::NonLabelDoStmt>>(x.t).source,
             "Loop control is not present in the DO LOOP"_err_en_US)
         .Attach(GetContext().directiveSource,
             "associated with the enclosing LOOP construct"_en_US);
+    return nullptr;
   }
-  return {nullptr, nullptr, nullptr, nullptr};
-}
-
-template <typename T>
-const parser::Name *DirectiveAttributeVisitor<T>::GetLoopIndex(
-    const parser::DoConstruct &x) {
-  return std::get<const parser::Name *>(GetLoopBounds(x));
 }
 
 template <typename T>
@@ -2021,10 +1990,6 @@ bool OmpAttributeVisitor::Pre(const parser::OpenMPLoopConstruct &x) {
       }
     }
   }
-
-  // Must be done before iv privatization
-  CheckPerfectNestAndRectangularLoop(x);
-
   PrivatizeAssociatedLoopIndexAndCheckLoopLevel(x);
   ordCollapseLevel = GetNumAffectedLoopsFromLoopConstruct(x) + 1;
   return true;
@@ -2220,116 +2185,6 @@ void OmpAttributeVisitor::CollectNumAffectedLoopsFromClauses(
   }
 }
 
-void OmpAttributeVisitor::CheckPerfectNestAndRectangularLoop(
-    const parser::OpenMPLoopConstruct &x) {
-  auto &dirContext{GetContext()};
-  std::int64_t dirDepth{dirContext.associatedLoopLevel};
-  if (dirDepth <= 0)
-    return;
-
-  auto checkExprHasSymbols = [&](llvm::SmallVector<Symbol *> &ivs,
-                                 const parser::ScalarExpr *bound) {
-    if (ivs.empty())
-      return;
-    auto boundExpr{semantics::AnalyzeExpr(context_, *bound)};
-    if (!boundExpr)
-      return;
-    semantics::UnorderedSymbolSet boundSyms{
-        evaluate::CollectSymbols(*boundExpr)};
-    if (boundSyms.empty())
-      return;
-    for (Symbol *iv : ivs) {
-      if (boundSyms.count(*iv) != 0) {
-        // TODO: Point to occurence of iv in boundExpr, directiveSource as a
-        //       note
-        context_.Say(dirContext.directiveSource,
-            "Trip count must be computable and invariant"_err_en_US);
-      }
-    }
-  };
-
-  // Find the associated region by skipping nested loop-associated constructs
-  // such as loop transformations
-  const parser::NestedConstruct *innermostAssocRegion{nullptr};
-  const parser::OpenMPLoopConstruct *innermostConstruct{&x};
-  while (const auto &innerAssocStmt{
-      std::get<std::optional<parser::NestedConstruct>>(
-          innermostConstruct->t)}) {
-    innermostAssocRegion = &(innerAssocStmt.value());
-    if (const auto *innerConstruct{
-            std::get_if<common::Indirection<parser::OpenMPLoopConstruct>>(
-                innermostAssocRegion)}) {
-      innermostConstruct = &innerConstruct->value();
-    } else {
-      break;
-    }
-  }
-
-  if (!innermostAssocRegion)
-    return;
-  const auto &outer{std::get_if<parser::DoConstruct>(innermostAssocRegion)};
-  if (!outer)
-    return;
-
-  llvm::SmallVector<Symbol *> ivs;
-  int curLevel{0};
-  const parser::DoConstruct *loop{outer};
-  while (true) {
-    auto [iv, lb, ub, step] = GetLoopBounds(*loop);
-
-    if (lb)
-      checkExprHasSymbols(ivs, lb);
-    if (ub)
-      checkExprHasSymbols(ivs, ub);
-    if (step)
-      checkExprHasSymbols(ivs, step);
-    if (iv) {
-      if (auto *symbol{currScope().FindSymbol(iv->source)})
-        ivs.push_back(symbol);
-    }
-
-    // Stop after processing all affected loops
-    if (curLevel + 1 >= dirDepth)
-      break;
-
-    // Recurse into nested loop
-    const auto &block{std::get<parser::Block>(loop->t)};
-    if (block.empty()) {
-      // Insufficient number of nested loops already reported by
-      // CheckAssocLoopLevel()
-      break;
-    }
-
-    loop = GetDoConstructIf(block.front());
-    if (!loop) {
-      // Insufficient number of nested loops already reported by
-      // CheckAssocLoopLevel()
-      break;
-    }
-
-    auto checkPerfectNest = [&, this]() {
-      auto blockSize = block.size();
-      if (blockSize <= 1)
-        return;
-
-      if (parser::Unwrap<parser::ContinueStmt>(x))
-        blockSize -= 1;
-
-      if (blockSize <= 1)
-        return;
-
-      // Non-perfectly nested loop
-      // TODO: Point to non-DO statement, directiveSource as a note
-      context_.Say(dirContext.directiveSource,
-          "Canonical loop nest must be perfectly nested."_err_en_US);
-    };
-
-    checkPerfectNest();
-
-    ++curLevel;
-  }
-}
-
 // 2.15.1.1 Data-sharing Attribute Rules - Predetermined
 //   - The loop iteration variable(s) in the associated do-loop(s) of a do,
 //     parallel do, taskloop, or distribute construct is (are) private.

flang/test/Semantics/OpenMP/do08.f90

@@ -61,7 +61,6 @@ program omp
   !$omp end do
 
 
-  !ERROR: Canonical loop nest must be perfectly nested.
   !ERROR: The value of the parameter in the COLLAPSE or ORDERED clause must not be larger than the number of nested loops following the construct.
   !$omp do collapse(3)
   do 60 i=2,200,2

flang/test/Semantics/OpenMP/do13.f90

@@ -59,7 +59,6 @@ program omp
   !$omp end do
 
 
-  !ERROR: Canonical loop nest must be perfectly nested.
   !ERROR: The value of the parameter in the COLLAPSE or ORDERED clause must not be larger than the number of nested loops following the construct.
   !$omp do collapse(3)
   do 60 i=1,10

flang/test/Semantics/OpenMP/do22.f90

@@ -25,3 +25,6 @@ need to resole API changes downstream
 breaks smoke flags, wgs64
 [clang] Use the VFS to get the OpenMP entry info (#160935)
 ---
+breaks 463.swim build
+[Flang] Add perfect-nest and rectangular-loop semantic tests (#160283)
+---