[Flang][OpenMP][Sema] Adding parsing and semantic support for scan directive. #102792

anchuraj · 2024-08-11T06:01:40Z

Scan directive specifies the scan computations. This PR adds the initial parsing and semantic support in flang.

scan is parsed as a stand alone directive as done in clang.

llvmbot · 2024-08-11T06:02:13Z

@llvm/pr-subscribers-flang-parser
@llvm/pr-subscribers-flang-semantics
@llvm/pr-subscribers-flang-openmp

@llvm/pr-subscribers-flang-fir-hlfir

Author: Anchu Rajendran S (anchuraj)

Changes

Scan directive specifies the scan computations. This PR adds the initial parsing and semantic support in flang.

Patch is 28.78 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/102792.diff

13 Files Affected:

(modified) flang/lib/Lower/OpenMP/OpenMP.cpp (+3)
(modified) flang/lib/Parser/openmp-parsers.cpp (+5)
(modified) flang/lib/Parser/unparse.cpp (+3)
(modified) flang/lib/Semantics/check-omp-structure.cpp (+20-12)
(modified) flang/lib/Semantics/resolve-directives.cpp (+16)
(added) flang/test/Parser/OpenMP/scan.f90 (+40)
(modified) flang/test/Semantics/OpenMP/do05.f90 (+4-4)
(modified) flang/test/Semantics/OpenMP/nested-barrier.f90 (+2-2)
(modified) flang/test/Semantics/OpenMP/nested-master.f90 (+1-1)
(modified) flang/test/Semantics/OpenMP/nested-simd.f90 (+17-17)
(modified) flang/test/Semantics/OpenMP/ordered-simd.f90 (+1-1)
(added) flang/test/Semantics/OpenMP/scan.f90 (+19)
(modified) llvm/include/llvm/Frontend/OpenMP/OMP.td (+2)

diff --git a/flang/lib/Lower/OpenMP/OpenMP.cpp b/flang/lib/Lower/OpenMP/OpenMP.cpp
index bbde77c14f36a1..52cc15d4ac6946 100644
--- a/flang/lib/Lower/OpenMP/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP/OpenMP.cpp
@@ -2189,6 +2189,9 @@ static void genOMPDispatch(lower::AbstractConverter &converter,
   case llvm::omp::Directive::OMPD_parallel:
     genStandaloneParallel(converter, symTable, semaCtx, eval, loc, queue, item);
     break;
+  case llvm::omp::Directive::OMPD_scan:
+    TODO(loc, "Unhandled directive " + llvm::omp::getOpenMPDirectiveName(dir));
+    break;
   case llvm::omp::Directive::OMPD_section:
     llvm_unreachable("genOMPDispatch: OMPD_section");
     // Lowered in the enclosing genSectionsOp.
diff --git a/flang/lib/Parser/openmp-parsers.cpp b/flang/lib/Parser/openmp-parsers.cpp
index 52789d6e5f0f6b..7c10099fe0da8b 100644
--- a/flang/lib/Parser/openmp-parsers.cpp
+++ b/flang/lib/Parser/openmp-parsers.cpp
@@ -267,6 +267,8 @@ TYPE_PARSER(
         construct<OmpClause>(construct<OmpClause::DynamicAllocators>()) ||
     "ENTER" >> construct<OmpClause>(construct<OmpClause::Enter>(
                    parenthesized(Parser<OmpObjectList>{}))) ||
+    "EXCLUSIVE" >> construct<OmpClause>(construct<OmpClause::Exclusive>(
+                         parenthesized(Parser<OmpObjectList>{}))) ||
     "FILTER" >> construct<OmpClause>(construct<OmpClause::Filter>(
                     parenthesized(scalarIntExpr))) ||
     "FINAL" >> construct<OmpClause>(construct<OmpClause::Final>(
@@ -286,6 +288,8 @@ TYPE_PARSER(
     "IF" >> construct<OmpClause>(construct<OmpClause::If>(
                 parenthesized(Parser<OmpIfClause>{}))) ||
     "INBRANCH" >> construct<OmpClause>(construct<OmpClause::Inbranch>()) ||
+    "INCLUSIVE" >> construct<OmpClause>(construct<OmpClause::Inclusive>(
+                         parenthesized(Parser<OmpObjectList>{}))) ||
     "IS_DEVICE_PTR" >> construct<OmpClause>(construct<OmpClause::IsDevicePtr>(
                            parenthesized(Parser<OmpObjectList>{}))) ||
     "LASTPRIVATE" >> construct<OmpClause>(construct<OmpClause::Lastprivate>(
@@ -481,6 +485,7 @@ TYPE_PARSER(sourced(construct<OpenMPFlushConstruct>(verbatim("FLUSH"_tok),
 TYPE_PARSER(sourced(construct<OmpSimpleStandaloneDirective>(first(
     "BARRIER" >> pure(llvm::omp::Directive::OMPD_barrier),
     "ORDERED" >> pure(llvm::omp::Directive::OMPD_ordered),
+    "SCAN" >> pure(llvm::omp::Directive::OMPD_scan),
     "TARGET ENTER DATA" >> pure(llvm::omp::Directive::OMPD_target_enter_data),
     "TARGET EXIT DATA" >> pure(llvm::omp::Directive::OMPD_target_exit_data),
     "TARGET UPDATE" >> pure(llvm::omp::Directive::OMPD_target_update),
diff --git a/flang/lib/Parser/unparse.cpp b/flang/lib/Parser/unparse.cpp
index 2511a5dda9d095..f252512a41f655 100644
--- a/flang/lib/Parser/unparse.cpp
+++ b/flang/lib/Parser/unparse.cpp
@@ -2295,6 +2295,9 @@ class UnparseVisitor {
     case llvm::omp::Directive::OMPD_barrier:
       Word("BARRIER ");
       break;
+    case llvm::omp::Directive::OMPD_scan:
+      Word("SCAN ");
+      break;
     case llvm::omp::Directive::OMPD_taskwait:
       Word("TASKWAIT ");
       break;
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index 50840898438c78..f38b929fb78b3d 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -550,17 +550,21 @@ void OmpStructureChecker::CheckSIMDNest(const parser::OpenMPConstruct &c) {
                         }
                       }
                     },
-                    [&](const parser::OpenMPSimpleStandaloneConstruct &c) {
-                      const auto &dir{
-                          std::get<parser::OmpSimpleStandaloneDirective>(c.t)};
-                      if (dir.v == llvm::omp::Directive::OMPD_ordered) {
-                        const auto &clauses{
-                            std::get<parser::OmpClauseList>(c.t)};
-                        for (const auto &clause : clauses.v) {
-                          if (std::get_if<parser::OmpClause::Simd>(&clause.u)) {
-                            eligibleSIMD = true;
-                            break;
+                    [&](const parser::OpenMPStandaloneConstruct &c) {
+                      if(const auto &simpleConstruct = std::get_if<parser::OpenMPSimpleStandaloneConstruct>(&c.u)) {
+                        const auto &dir{
+                            std::get<parser::OmpSimpleStandaloneDirective>(simpleConstruct->t)};
+                        if (dir.v == llvm::omp::Directive::OMPD_ordered) {
+                          const auto &clauses{
+                              std::get<parser::OmpClauseList>(simpleConstruct->t)};
+                          for (const auto &clause : clauses.v) {
+                            if (std::get_if<parser::OmpClause::Simd>(&clause.u)) {
+                              eligibleSIMD = true;
+                              break;
+                            }
                           }
+                        } else if(dir.v == llvm::omp::Directive::OMPD_scan) {
+                          eligibleSIMD = true;
                         }
                       }
                     },
@@ -571,6 +575,7 @@ void OmpStructureChecker::CheckSIMDNest(const parser::OpenMPConstruct &c) {
                       const auto &beginDir{
                           std::get<parser::OmpLoopDirective>(beginLoopDir.t)};
                       if ((beginDir.v == llvm::omp::Directive::OMPD_simd) ||
+                          (beginDir.v == llvm::omp::Directive::OMPD_parallel_do_simd) ||
                           (beginDir.v == llvm::omp::Directive::OMPD_do_simd)) {
                         eligibleSIMD = true;
                       }
@@ -586,8 +591,9 @@ void OmpStructureChecker::CheckSIMDNest(const parser::OpenMPConstruct &c) {
     context_.Say(parser::FindSourceLocation(c),
         "The only OpenMP constructs that can be encountered during execution "
         "of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, "
-        "the `SIMD` construct and the `ORDERED` construct with the `SIMD` "
-        "clause."_err_en_US);
+        "the `SIMD` construct, the `SCAN` construct and the `ORDERED` "
+        "construct "
+        "with the `SIMD` clause."_err_en_US);
   }
 }
 
@@ -2531,6 +2537,8 @@ void OmpStructureChecker::CheckReductionModifier(
     switch (dirCtx.directive) {
     case llvm::omp::Directive::OMPD_do: // worksharing-loop
     case llvm::omp::Directive::OMPD_do_simd: // worksharing-loop simd
+    case llvm::omp::Directive::OMPD_parallel_do_simd: // worksharing-parallel-loop
+                                                      // simd
     case llvm::omp::Directive::OMPD_simd: // "simd"
       break;
     default:
diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index d635a7b8b7874f..018352f072a112 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -1578,9 +1578,11 @@ bool OmpAttributeVisitor::Pre(
     const parser::OpenMPSimpleStandaloneConstruct &x) {
   const auto &standaloneDir{
       std::get<parser::OmpSimpleStandaloneDirective>(x.t)};
+  const auto &parentContext{GetContextIf()};
   switch (standaloneDir.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:
   case llvm::omp::Directive::OMPD_target_update:
@@ -1591,6 +1593,20 @@ bool OmpAttributeVisitor::Pre(
   default:
     break;
   }
+  if (standaloneDir.v == llvm::omp::Directive::OMPD_scan) {
+    if ((std::get<parser::OmpClauseList>(x.t).v.size() != 1)) {
+      context_.Say(standaloneDir.source,
+          "Exactly one of `exclusive` or `inclusive` clause is expected"_err_en_US);
+    }
+    if (!parentContext ||
+        (llvm::omp::getDirectiveAssociation(parentContext->directive) !=
+            llvm::omp::Association::Loop)) {
+      context_.Say(standaloneDir.source,
+          "Orphaned `omp scan` directives are prohibited; perhaps you forgot to "
+          "enclose the directive in to a worksharing loop, a worksharing loop "
+          "simd or a simd directive."_err_en_US);
+    }
+  }
   ClearDataSharingAttributeObjects();
   return true;
 }
diff --git a/flang/test/Parser/OpenMP/scan.f90 b/flang/test/Parser/OpenMP/scan.f90
new file mode 100644
index 00000000000000..a6e23ac9404882
--- /dev/null
+++ b/flang/test/Parser/OpenMP/scan.f90
@@ -0,0 +1,40 @@
+! RUN: %flang_fc1 -fdebug-unparse -fopenmp %s | FileCheck --ignore-case %s
+! RUN: %flang_fc1 -fdebug-dump-parse-tree -fopenmp %s | FileCheck --check-prefix="PARSE-TREE" %s
+
+! Check for parsing scan directive
+subroutine test_scan_inclusive()
+  implicit none
+  integer, parameter :: n = 100
+  integer a(n), b(n)
+  integer x, k
+
+  ! initialization
+  x = 0
+  do k = 1, n
+   a(k) = k
+  end do
+
+  ! a(k) is included in the computation of producing results in b(k)
+  !$omp parallel do simd reduction(inscan,+: x)
+  do k = 1, n
+    x = x + a(k)
+    !PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPStandaloneConstruct -> OpenMPSimpleStandaloneConstruct
+    !PARSE-TREE-NEXT: OmpSimpleStandaloneDirective -> llvm::omp::Directive = scan
+    !PARSE-TREE-NEXT: OmpClauseList -> OmpClause -> Inclusive -> OmpObjectList -> OmpObject -> Designator -> DataRef -> Name = 'x'
+    !CHECK: !$omp scan inclusive(x)
+    !$omp scan inclusive(x)
+      b(k) = x
+  end do
+
+  ! a(k) is not included in the computation of producing results in b(k)
+  !$omp parallel do simd reduction(inscan,+: x)
+  do k = 1, n
+    b(k) = x
+    !PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPStandaloneConstruct -> OpenMPSimpleStandaloneConstruct
+    !PARSE-TREE-NEXT: OmpSimpleStandaloneDirective -> llvm::omp::Directive = scan
+    !PARSE-TREE-NEXT: OmpClauseList -> OmpClause -> Exclusive -> OmpObjectList -> OmpObject -> Designator -> DataRef -> Name = 'x'
+    !CHECK: !$omp scan exclusive(x)
+    !$omp scan exclusive(x)
+    x = x + a(k)
+  end do
+end subroutine
diff --git a/flang/test/Semantics/OpenMP/do05.f90 b/flang/test/Semantics/OpenMP/do05.f90
index c0f240db57b65b..24844f9fe4f62a 100644
--- a/flang/test/Semantics/OpenMP/do05.f90
+++ b/flang/test/Semantics/OpenMP/do05.f90
@@ -39,7 +39,7 @@ program omp_do
     if( i == 5 ) then
         cycle
     end if
-    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
     !ERROR: A worksharing region may not be closely nested inside a worksharing, explicit task, taskloop, critical, ordered, atomic, or master region
     !$omp single
     do j=1,10
@@ -70,7 +70,7 @@ program omp_do
     if( i == 3 ) then
         cycle
     end if
-    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
     !ERROR: A worksharing region may not be closely nested inside a worksharing, explicit task, taskloop, critical, ordered, atomic, or master region
     !$omp single
     do j=1,10
@@ -93,7 +93,7 @@ program omp_do
 
   !$omp target parallel do simd
   do i=1,10
-    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
     !ERROR: A worksharing region may not be closely nested inside a worksharing, explicit task, taskloop, critical, ordered, atomic, or master region
     !$omp single
     do j=1,10
@@ -116,7 +116,7 @@ program omp_do
 
   !$omp target teams distribute parallel do simd
   do i=1,10
-    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
     !ERROR: A worksharing region may not be closely nested inside a worksharing, explicit task, taskloop, critical, ordered, atomic, or master region
     !$omp single
     do j=1,10
diff --git a/flang/test/Semantics/OpenMP/nested-barrier.f90 b/flang/test/Semantics/OpenMP/nested-barrier.f90
index aae283229e330d..ed13c98539c93c 100644
--- a/flang/test/Semantics/OpenMP/nested-barrier.f90
+++ b/flang/test/Semantics/OpenMP/nested-barrier.f90
@@ -17,7 +17,7 @@ program omp_nest_barrier
   !$omp do simd
   do i = 1, 10
     k = k + 1
-    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
     !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
     !$omp barrier
     j = j -1
@@ -34,7 +34,7 @@ program omp_nest_barrier
   !$omp parallel do simd
   do i = 1, 10
     k = k + 1
-    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
     !ERROR: `BARRIER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`,`CRITICAL`, `ORDERED`, `ATOMIC` or `MASTER` region.
     !$omp barrier
     j = j -1
diff --git a/flang/test/Semantics/OpenMP/nested-master.f90 b/flang/test/Semantics/OpenMP/nested-master.f90
index 069de67cafae28..0a5118bb947550 100644
--- a/flang/test/Semantics/OpenMP/nested-master.f90
+++ b/flang/test/Semantics/OpenMP/nested-master.f90
@@ -64,7 +64,7 @@ program omp_nest_master
   do i = 1, 10
     k = k + 1
     !WARNING: OpenMP directive 'master' has been deprecated, please use 'masked' instead.
-    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+    !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
     !ERROR: `MASTER` region may not be closely nested inside of `WORKSHARING`, `LOOP`, `TASK`, `TASKLOOP`, or `ATOMIC` region.
     !$omp master
     j = j -1
diff --git a/flang/test/Semantics/OpenMP/nested-simd.f90 b/flang/test/Semantics/OpenMP/nested-simd.f90
index 4149b6d97e9dc7..c9fb90cdeceb25 100644
--- a/flang/test/Semantics/OpenMP/nested-simd.f90
+++ b/flang/test/Semantics/OpenMP/nested-simd.f90
@@ -40,7 +40,7 @@ SUBROUTINE NESTED_BAD(N)
       !$OMP ORDERED SIMD
       DO J = 1,N
         print *, "Hi"
-        !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+        !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
         !ERROR: TEAMS region can only be strictly nested within the implicit parallel region or TARGET region
         !$omp teams 
          DO K = 1,N
@@ -58,25 +58,25 @@ SUBROUTINE NESTED_BAD(N)
     !$OMP ATOMIC
     K =  K + 1
     IF (I <= 10) THEN
-      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
       !$omp task 
       do J = 1, N
         K = 2
       end do
       !$omp end task
-      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
       !$omp target 
       do J = 1, N
         K = 2
       end do
       !$omp end target
-      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
       !$OMP DO
       DO J = 1,N
         A(J) = J
       END DO
       !$OMP END DO
-      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
       !$OMP PARALLEL DO
       DO J = 1,N
         A(J) = J
@@ -91,26 +91,26 @@ SUBROUTINE NESTED_BAD(N)
     !$OMP ATOMIC
     K =  K + 1
     IF (I <= 10) THEN
-      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct, the `SCAN` construct and the `ORDERED` construct with the `SIMD` clause.
       !$omp task 
       do J = 1, N
         K = 2
       end do
       !$omp end task
-      !ERROR: The only OpenMP constructs that can be encountered during execution of a 'SIMD' region are the `ATOMIC` construct, the `LOOP` construct, the `SIMD` construct and the `ORDERED` construct with the `SIMD` clause.
+      !ERROR:...
[truncated]

github-actions · 2024-08-11T06:05:17Z

✅ With the latest revision this PR passed the C/C++ code formatter.

skatrak

Thank you Anchu, I just have one remaining concern. I hope someone else can share their thoughts on it and get this work merged soon.

skatrak · 2024-09-30T15:12:59Z

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

@@ -198,6 +198,10 @@ class DirectiveStructureChecker : public virtual BaseChecker {
    ClauseMapTy clauseInfo;
    std::list<C> actualClauses;
    std::list<C> crtGroup;
+    std::set<std::string> usedInScanDirective;


After our private discussion, I'm not against representing symbols as strings as part of this PR and address not matching symbols as part of a separate PR, if there's actually a semantics bug causing this mismatch.

What I'm still not sure about is having these new OpenMP-specific properties added to the generic DirectiveContext. Perhaps someone from the OpenACC side can chime in on this (@clementval, @jeanPerier).

skatrak · 2024-10-01T09:49:24Z

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

+            std::get_if<parser::OmpClause::Reduction>(&clause.u)}) {
+      const auto &maybeModifier{
+          std::get<std::optional<ReductionModifier>>(reductionClause->v.t)};
+      if (maybeModifier && *maybeModifier == ReductionModifier::Inscan) {


Nit: Reduce the nesting level to make code easier to follow.

Suggested change

if (maybeModifier && *maybeModifier == ReductionModifier::Inscan) {

if (!maybeModifier || *maybeModifier != ReductionModifier::Inscan)

continue;

Generally frontend code in flang is more nested.

I prefer to go with the existing approach as personally I feel it more readable. Please let me know if there are suggestions otherwise.

skatrak · 2024-10-01T10:07:09Z

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

+    const parser::OmpObjectList &x) {
+  for (const auto &ompObj : x.v) {
+    auto checkScanSymbolInReduction = [&](const parser::Name *name) {
+      if (name->symbol) {


Nit: I think an early return here instead of adding a nesting level helps readability.

Suggested change

if (name->symbol) {

if (!name->symbol)

return;

Generally frontend code in flang is nested.

kiranchandramohan

A few comments.

kiranchandramohan · 2024-10-27T22:17:50Z

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

+        "Orphaned `omp scan` directives are prohibited; perhaps you forgot "
+        "to enclose the directive in to a worksharing loop, a worksharing "
+        "loop simd or a simd directive."_err_en_US);


Suggested change

"Orphaned `omp scan` directives are prohibited; perhaps you forgot "

"to enclose the directive in to a worksharing loop, a worksharing "

"loop simd or a simd directive."_err_en_US);

"Orphaned SCAN directives are prohibited, perhaps you forgot "

"to enclose the directive in a WORKSHARING LOOP, a WORKSHARING "

"LOOP SIMD or a SIMD directive."_err_en_US);

kiranchandramohan · 2024-10-27T22:18:12Z

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

+    const parser::OpenMPSimpleStandaloneConstruct &x) {
+  if (std::get<parser::OmpClauseList>(x.t).v.size() != 1) {
+    context_.Say(x.source,
+        "Exactly one of `exclusive` or `inclusive` clause is expected"_err_en_US);


Suggested change

"Exactly one of `exclusive` or `inclusive` clause is expected"_err_en_US);

"Exactly one of EXCLUSIVE or INCLUSIVE clause is expected"_err_en_US);

kiranchandramohan · 2024-10-27T22:18:50Z

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

+                  "List item %s must appear in 'inclusive' or "
+                  "'exclusive' clause of an "
+                  "enclosed scan directive"_err_en_US,


Suggested change

"List item %s must appear in 'inclusive' or "

"'exclusive' clause of an "

"enclosed scan directive"_err_en_US,

"List item %s must appear in INCLUSIVE or "

"EXCLUSIVE clause of an "

"enclosed SCAN directive"_err_en_US,

kiranchandramohan · 2024-10-27T22:24:26Z

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

+            std::get_if<parser::OmpClause::Reduction>(&clause.u)}) {
+      const auto &maybeModifier{
+          std::get<std::optional<ReductionModifier>>(reductionClause->v.t)};
+      if (maybeModifier && *maybeModifier == ReductionModifier::Inscan) {


Generally frontend code in flang is more nested.

kiranchandramohan · 2024-10-27T22:25:14Z

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

+    const parser::OmpObjectList &x) {
+  for (const auto &ompObj : x.v) {
+    auto checkScanSymbolInReduction = [&](const parser::Name *name) {
+      if (name->symbol) {


Generally frontend code in flang is nested.

kiranchandramohan · 2024-10-27T22:25:51Z

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

+                "List item %s must appear in 'reduction' clause "
+                "with the 'inscan' modifier of the parent "
+                "directive"_err_en_US,


Suggested change

"List item %s must appear in 'reduction' clause "

"with the 'inscan' modifier of the parent "

"directive"_err_en_US,

"List item %s must appear in a REDUCTION clause "

"with the INSCAN modifier of the parent "

"directive"_err_en_US,

kiranchandramohan · 2024-10-27T22:31:22Z

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

@@ -198,6 +198,10 @@ class DirectiveStructureChecker : public virtual BaseChecker {
    ClauseMapTy clauseInfo;
    std::list<C> actualClauses;
    std::list<C> crtGroup;
+    std::set<std::string> usedInScanDirective;


I agree with @skatrak's initial comments. We should try to keep the OpenMP specific data-structures in the OpenMP specific checkers. And if we can use the symbol that would be great. If the reduction creates a new private symbol, that should be the symbol bound to the inclusive or exclusive clause of the SCAN directive.

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

flang/lib/Semantics/resolve-directives.cpp

kiranchandramohan · 2024-11-12T23:18:49Z

flang/lib/Semantics/resolve-directives.cpp

+
+  bool Pre(const parser::OmpClause::Inclusive &x) {
+    const auto &objectList{x.v};
+    ResolveNames(objectList);


Can you add a debug-dump-symbols test?

I have added a new flag and dumped the symbols in a new test.

kiranchandramohan · 2024-11-12T23:16:40Z

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

 void OmpStructureChecker::CheckBarrierNesting(
    const parser::OpenMPSimpleStandaloneConstruct &x) {
  // A barrier region may not be `closely nested` inside a worksharing, loop,
  // task, taskloop, critical, ordered, atomic, or master region.
  // TODO:  Expand the check to include `LOOP` construct as well when it is
  // supported.
-  if (GetContext().directive == llvm::omp::Directive::OMPD_barrier) {


Was this check for barrier not required?

I moved the check to the caller (@line 1906) since I needed a function for scan as well.

kiranchandramohan · 2024-11-12T23:30:52Z

flang/lib/Semantics/resolve-directives.cpp

@@ -2865,4 +2879,19 @@ void OmpAttributeVisitor::IssueNonConformanceWarning(
    context_.Say(source, "%s"_warn_en_US, warnStr);
  }
 }
+void OmpAttributeVisitor::ResolveNames(const parser::OmpObjectList &objList) {


I am a bit surprised that we needed to define this function. Was the resolution of names not handled anywhere else?

Thank you for pointing this out. I believe I was not understanding the existing code well. I made use of ResolveOmpObjList function now.

…eck-omp-structure

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

kiranchandramohan

LGTM. Nice work.

skatrak

LGTM, thanks!

…114737) Scan directive allows to specify scan reductions within an worksharing loop, worksharing loop simd or simd directive which should have an `InScan` modifier associated with it. This change adds the mlir support for the same. Related PR: [Parsing and Semantic Support for scan](#102792)

…support (#114737) Scan directive allows to specify scan reductions within an worksharing loop, worksharing loop simd or simd directive which should have an `InScan` modifier associated with it. This change adds the mlir support for the same. Related PR: [Parsing and Semantic Support for scan](llvm/llvm-project#102792)

anchuraj requested review from shraiysh and kparzysz August 11, 2024 06:01

llvmbot added flang Flang issues not falling into any other category flang:fir-hlfir flang:openmp flang:semantics flang:parser clang:openmp OpenMP related changes to Clang labels Aug 11, 2024

anchuraj requested review from skatrak, mjklemm and klausler August 11, 2024 06:02

anchuraj removed request for skatrak, mjklemm, klausler, shraiysh and kparzysz August 12, 2024 03:52

anchuraj force-pushed the scan-parse branch 4 times, most recently from 9a045a6 to 5bf0f84 Compare August 13, 2024 19:30

anchuraj requested review from skatrak, mjklemm, klausler, shraiysh and kparzysz and removed request for skatrak August 14, 2024 16:37

klausler removed their request for review August 17, 2024 19:58

kiranchandramohan mentioned this pull request Sep 25, 2024

[Flang][OpenMP] Important issues to be fixed prior to removing experimental status of OpenMP #110008

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skatrak reviewed Oct 1, 2024

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anchuraj force-pushed the scan-parse branch 2 times, most recently from 81f37c2 to 9e4724c Compare November 12, 2024 23:22

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anchuraj added 7 commits November 13, 2024 00:00

Adding parsing support for scan directive.

ee14b03

R2: Addressing review comments

615a759

R3: Adding formatted file

a0480ca

R4: Addressing review comments

9b8dbd9

R5: Addressing a few more review comments

865ca2e

R6: Reworked to add a few more semantic checks and moved checks to ch…

6409cd9

…eck-omp-structure

R7: Addressed a few review comments

b10a198

anchuraj force-pushed the scan-parse branch from 9e4724c to d3119cc Compare November 13, 2024 06:02

R8: converting string refs to symbol* and merging the new changes

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anchuraj force-pushed the scan-parse branch from d3119cc to 9facbf7 Compare November 13, 2024 06:39

R9: Addressing review comments

8464253

anchuraj force-pushed the scan-parse branch from d39c966 to 8464253 Compare November 13, 2024 23:28

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R10: Re-implementing a few checks by removing stack

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kiranchandramohan approved these changes Nov 15, 2024

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anchuraj merged commit e67e09a into llvm:main Nov 15, 2024
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anchuraj mentioned this pull request Nov 18, 2024

[mlir][OpenMP] inscan reduction modifier and scan op mlir support #114737

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anchuraj mentioned this pull request Jan 22, 2025

[flang][openmp] Changes for invoking scan Op #123254

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[Flang][OpenMP][Sema] Adding parsing and semantic support for scan directive. #102792

[Flang][OpenMP][Sema] Adding parsing and semantic support for scan directive. #102792

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	if (maybeModifier && *maybeModifier == ReductionModifier::Inscan) {
	if (!maybeModifier \|\| *maybeModifier != ReductionModifier::Inscan)
	continue;

	"Exactly one of `exclusive` or `inclusive` clause is expected"_err_en_US);
	"Exactly one of EXCLUSIVE or INCLUSIVE clause is expected"_err_en_US);

[Flang][OpenMP][Sema] Adding parsing and semantic support for scan directive. #102792

[Flang][OpenMP][Sema] Adding parsing and semantic support for scan directive. #102792

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