[FLANG][OpenMP]Add support for ALIGN clause on OMP ALLOCATE

flang/include/flang/Parser/dump-parse-tree.h

@@ -486,6 +486,7 @@ class ParseTreeDumper {
   NODE(parser, OmpAffinityClause)
   NODE(OmpAffinityClause, Modifier)
   NODE(parser, OmpAlignment)
+  NODE(parser, OmpAlignClause)
   NODE(parser, OmpAlignedClause)
   NODE(OmpAlignedClause, Modifier)
   NODE(parser, OmpAtClause)

flang/include/flang/Parser/parse-tree.h

@@ -3752,6 +3752,11 @@ struct OmpAffinityClause {
   std::tuple<MODIFIERS(), OmpObjectList> t;
 };
 
+// Ref: 5.2: [174]
+struct OmpAlignClause {
+  WRAPPER_CLASS_BOILERPLATE(OmpAlignClause, ScalarIntExpr);
+};
+
 // Ref: [4.5:72-81], [5.0:110-119], [5.1:134-143], [5.2:169-170]
 //
 // aligned-clause ->

flang/lib/Parser/openmp-parsers.cpp

@@ -567,6 +567,8 @@ TYPE_PARSER(construct<OmpBindClause>(
     "TEAMS" >> pure(OmpBindClause::Binding::Teams) ||
     "THREAD" >> pure(OmpBindClause::Binding::Thread)))
 
+TYPE_PARSER(construct<OmpAlignClause>(scalarIntExpr))
+
 TYPE_PARSER(construct<OmpAtClause>(
     "EXECUTION" >> pure(OmpAtClause::ActionTime::Execution) ||
     "COMPILATION" >> pure(OmpAtClause::ActionTime::Compilation)))
@@ -582,6 +584,8 @@ TYPE_PARSER(
     "ACQ_REL" >> construct<OmpClause>(construct<OmpClause::AcqRel>()) ||
     "AFFINITY" >> construct<OmpClause>(construct<OmpClause::Affinity>(
                       parenthesized(Parser<OmpAffinityClause>{}))) ||
+    "ALIGN" >> construct<OmpClause>(construct<OmpClause::Align>(
+                   parenthesized(Parser<OmpAlignClause>{}))) ||
     "ALIGNED" >> construct<OmpClause>(construct<OmpClause::Aligned>(
                      parenthesized(Parser<OmpAlignedClause>{}))) ||
     "ALLOCATE" >> construct<OmpClause>(construct<OmpClause::Allocate>(

flang/lib/Semantics/check-omp-structure.cpp

@@ -1483,11 +1483,24 @@ void OmpStructureChecker::Leave(const parser::OpenMPRequiresConstruct &) {
   dirContext_.pop_back();
 }
 
+void OmpStructureChecker::CheckAlignValue(const parser::OmpClause &clause) {
+  if (auto *align{std::get_if<parser::OmpClause::Align>(&clause.u)}) {
+    if (const auto &v{GetIntValue(align->v)}; !v || *v <= 0) {
+      context_.Say(clause.source,
+          "The alignment value should be a constant positive integer"_err_en_US);
+    }
+  }
+}
+
 void OmpStructureChecker::Enter(const parser::OpenMPDeclarativeAllocate &x) {
   isPredefinedAllocator = true;
   const auto &dir{std::get<parser::Verbatim>(x.t)};
   const auto &objectList{std::get<parser::OmpObjectList>(x.t)};
   PushContextAndClauseSets(dir.source, llvm::omp::Directive::OMPD_allocate);
+  const auto &clauseList{std::get<parser::OmpClauseList>(x.t)};
+  for (const auto &clause : clauseList.v) {
+    CheckAlignValue(clause);
+  }
   CheckIsVarPartOfAnotherVar(dir.source, objectList);
 }
 
@@ -1704,6 +1717,10 @@ void OmpStructureChecker::Enter(const parser::OpenMPExecutableAllocate &x) {
   const auto &dir{std::get<parser::Verbatim>(x.t)};
   const auto &objectList{std::get<std::optional<parser::OmpObjectList>>(x.t)};
   PushContextAndClauseSets(dir.source, llvm::omp::Directive::OMPD_allocate);
+  const auto &clauseList{std::get<parser::OmpClauseList>(x.t)};
+  for (const auto &clause : clauseList.v) {
+    CheckAlignValue(clause);
+  }
   if (objectList) {
     CheckIsVarPartOfAnotherVar(dir.source, *objectList);
   }

flang/lib/Semantics/check-omp-structure.h

@@ -261,6 +261,8 @@ class OmpStructureChecker
   void CheckAllowedRequiresClause(llvmOmpClause clause);
   bool deviceConstructFound_{false};
 
+  void CheckAlignValue(const parser::OmpClause &);
+
   void EnterDirectiveNest(const int index) { directiveNest_[index]++; }
   void ExitDirectiveNest(const int index) { directiveNest_[index]--; }
   int GetDirectiveNest(const int index) { return directiveNest_[index]; }

flang/test/Lower/OpenMP/Todo/omp-declarative-allocate-align.f90

@@ -0,0 +1,10 @@
+! This test checks lowering of OpenMP allocate Directive with align clause.
+
+// RUN: not flang -fc1 -emit-fir -fopenmp %s 2>&1 | FileCheck %s
+
+program main
+  integer :: x
+
+  // CHECK: not yet implemented: OpenMPDeclarativeAllocate
+  !$omp allocate(x) align(32)
+end

flang/test/Parser/OpenMP/allocate-align-tree.f90

@@ -0,0 +1,42 @@
+! REQUIRES: openmp_runtime
+
+! RUN: %flang_fc1 %openmp_flags -fopenmp-version=51 -fdebug-dump-parse-tree %s | FileCheck %s
+! RUN: %flang_fc1 %openmp_flags -fdebug-unparse -fopenmp-version=51 %s | FileCheck %s --check-prefix="UNPARSE"
+! Ensures associated declarative OMP allocations are nested in their
+! corresponding executable allocate directive
+
+program allocate_align_tree
+    use omp_lib
+    integer, allocatable :: j(:), xarray(:)
+    integer :: z, t
+    t = 2
+    z = 3
+!$omp allocate(j) align(16)
+!$omp allocate(xarray) align(32) allocator(omp_large_cap_mem_alloc)
+    allocate(j(z), xarray(t))
+end program allocate_align_tree
+
+!CHECK: | | DeclarationConstruct -> SpecificationConstruct -> TypeDeclarationStmt
+!CHECK-NEXT: | | | DeclarationTypeSpec -> IntrinsicTypeSpec -> IntegerTypeSpec ->
+!CHECK-NEXT: | | | AttrSpec -> Allocatable
+!CHECK-NEXT: | | | EntityDecl
+!CHECK-NEXT: | | | | Name = 'j'
+
+
+!CHECK: | | ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPExecutableAllocate
+!CHECK-NEXT: | | | Verbatim
+!CHECK-NEXT: | | | OmpObjectList -> OmpObject -> Designator -> DataRef -> Name = 'xarray'
+!CHECK-NEXT: | | | OmpClauseList -> OmpClause -> Align -> OmpAlignClause -> Scalar -> Integer -> Expr = '32_4'
+!CHECK-NEXT: | | | | LiteralConstant -> IntLiteralConstant = '32'
+!CHECK-NEXT: | | | OmpClause -> Allocator -> Scalar -> Integer -> Expr = '2_8'
+!CHECK-NEXT: | | | | Designator -> DataRef -> Name = 'omp_large_cap_mem_alloc'
+!CHECK-NEXT: | | | OpenMPDeclarativeAllocate
+!CHECK-NEXT: | | | | Verbatim
+!CHECK-NEXT: | | | | OmpObjectList -> OmpObject -> Designator -> DataRef -> Name = 'j'
+!CHECK-NEXT: | | | | OmpClauseList -> OmpClause -> Align -> OmpAlignClause -> Scalar -> Integer -> Expr = '16_4'
+!CHECK-NEXT: | | | | | LiteralConstant -> IntLiteralConstant = '16'
+!CHECK-NEXT: | | | AllocateStmt
+
+!UNPARSE: !$OMP ALLOCATE (j) ALIGN(16_4)
+!UNPARSE: !$OMP ALLOCATE (xarray) ALIGN(32_4) ALLOCATOR(2_8)
+!UNPARSE-NEXT: ALLOCATE(j(z), xarray(t))

flang/test/Parser/OpenMP/allocate-unparse.f90

@@ -5,7 +5,7 @@ program allocate_unparse
 use omp_lib
 
 real, dimension (:,:), allocatable :: darray
-integer :: a, b, m, n, t, x, y, z
+integer :: a, b, j, m, n, t, x, y, z
 
 ! 2.11.3 declarative allocate
 
@@ -25,6 +25,7 @@ program allocate_unparse
 !$omp allocate(z) allocator(omp_default_mem_alloc)
 !$omp allocate(m) allocator(omp_default_mem_alloc)
 !$omp allocate(n)
+!$omp allocate(j) align(16)
     allocate ( darray(z, t) )
 
 end program allocate_unparse
@@ -41,4 +42,5 @@ end program allocate_unparse
 !CHECK:!$OMP ALLOCATE (z) ALLOCATOR(omp_default_mem_alloc)
 !CHECK:!$OMP ALLOCATE (m) ALLOCATOR(omp_default_mem_alloc)
 !CHECK:!$OMP ALLOCATE (n)
+!CHECK:!$OMP ALLOCATE (j) ALIGN(16)
 !CHECK:ALLOCATE(darray(z,t))

flang/test/Semantics/OpenMP/allocate-align01.f90

@@ -0,0 +1,20 @@
+! REQUIRES: openmp_runtime
+
+! RUN: %python %S/../test_errors.py %s %flang_fc1 %openmp_flags -fopenmp-version=51
+! OpenMP Version 5.2
+! The allocate clause's allocator modifier must be of type allocator_handle
+! and the align modifier must be constant, positive integer expression
+
+program allocate_align_tree
+    use omp_lib
+    integer, allocatable :: j(:), xarray(:)
+    integer :: z, t, xx
+    t = 2
+    z = 3
+    !ERROR: The alignment value should be a constant positive integer
+!$omp allocate(j) align(xx)
+    !ERROR: The alignment value should be a constant positive integer
+!$omp allocate(xarray) align(-32) allocator(omp_large_cap_mem_alloc)
+    allocate(j(z), xarray(t))
+end program allocate_align_tree
+

llvm/include/llvm/Frontend/OpenMP/OMP.td

@@ -49,6 +49,7 @@ def OMPC_Affinity : Clause<"affinity"> {
 }
 def OMPC_Align : Clause<"align"> {
   let clangClass = "OMPAlignClause";
+  let flangClass = "OmpAlignClause";
 }
 def OMPC_Aligned : Clause<"aligned"> {
   let clangClass = "OMPAlignedClause";