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

This is trivially additional support for the existing ALLOCATE
directive, which allows an ALIGN clause.

The ALLOCATE directive is currently not implemented, so this is
just addding the necessary parser parts to allow the compiler
to not say "Huh? I don't get this" [or "Expected OpenMP construct"]
when it encounters the ALIGN clause.

Some parser testing is updated and a new todo test, just in
case the feature of align clause is not supported by the initial
support for ALLOCATE.

Author: Leporacanthicus

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/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 +1,30 @@
+! 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_tree
+    use omp_lib
+    integer, allocatable :: j
+!$omp allocate(j) align(16)    
+    allocate(j)
+end program allocate_tree
+
+!CHECK: | | DeclarationConstruct -> SpecificationConstruct -> TypeDeclarationStmt
+!CHECK-NEXT: | | | DeclarationTypeSpec -> IntrinsicTypeSpec -> IntegerTypeSpec ->
+!CHECK-NEXT: | | | AttrSpec -> Allocatable
+!CHECK-NEXT: | | | EntityDecl
+!CHECK-NEXT: | | | | Name = 'j'
+
+
+!CHECK: | | ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPExecutableAllocate
+!CHECK-NEXT: | | | Verbatim
+!CHECK-NEXT: | | | OmpObjectList -> OmpObject -> Designator -> DataRef -> Name = 'j'
+!CHECK-NEXT: | | | OmpClauseList -> OmpClause -> Align -> OmpAlignClause -> Scalar -> Integer -> Expr = '16_4'
+!CHECK-NEXT: | | | | LiteralConstant -> IntLiteralConstant = '16'
+!CHECK-NEXT: | | | AllocateStmt
+
+!UNPARSE: !$OMP ALLOCATE (j) ALIGN(16_4)
+!UNPARSE-NEXT: ALLOCATE(j)

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))

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";