Reapply [flang][OpenMP] Avoid early returns, NFC llvm#117231 (llvm#117325)

Two PRs were merged at the same time: one that modified `maybeApplyToV`
function, and shortly afterwards, this (the reverted) one that had the
old definition.

During the merge both definitions were retained leading to compilation
errors.

Reapply the reverted PR (1a08b15) with the duplicate removed.

Author: kparzysz

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

@@ -2875,45 +2875,41 @@ void OmpStructureChecker::Enter(const parser::OmpClause::Reduction &x) {
 
 bool OmpStructureChecker::CheckReductionOperators(
     const parser::OmpClause::Reduction &x) {
+  bool ok = false;
   auto &modifiers{OmpGetModifiers(x.v)};
-  const auto *definedOp{
-      OmpGetUniqueModifier<parser::OmpReductionIdentifier>(modifiers)};
-  if (!definedOp) {
-    return false;
+  if (const auto *ident{
+          OmpGetUniqueModifier<parser::OmpReductionIdentifier>(modifiers)}) {
+
+    auto visitOperator{[&](const parser::DefinedOperator &dOpr) {
+      if (const auto *intrinsicOp{
+              std::get_if<parser::DefinedOperator::IntrinsicOperator>(
+                  &dOpr.u)}) {
+        ok = CheckIntrinsicOperator(*intrinsicOp);
+      } else {
+        context_.Say(GetContext().clauseSource,
+            "Invalid reduction operator in REDUCTION clause."_err_en_US,
+            ContextDirectiveAsFortran());
+      }
+    }};
+
+    auto visitDesignator{[&](const parser::ProcedureDesignator &procD) {
+      const parser::Name *name{std::get_if<parser::Name>(&procD.u)};
+      if (name && name->symbol) {
+        const SourceName &realName{name->symbol->GetUltimate().name()};
+        if (realName == "max" || realName == "min" || realName == "iand" ||
+            realName == "ior" || realName == "ieor") {
+          ok = true;
+        }
+      }
+      if (!ok) {
+        context_.Say(GetContext().clauseSource,
+            "Invalid reduction identifier in REDUCTION "
+            "clause."_err_en_US,
+            ContextDirectiveAsFortran());
+      }
+    }};
+    common::visit(common::visitors{visitOperator, visitDesignator}, ident->u);
   }
-  bool ok = false;
-  common::visit(
-      common::visitors{
-          [&](const parser::DefinedOperator &dOpr) {
-            if (const auto *intrinsicOp{
-                    std::get_if<parser::DefinedOperator::IntrinsicOperator>(
-                        &dOpr.u)}) {
-              ok = CheckIntrinsicOperator(*intrinsicOp);
-            } else {
-              context_.Say(GetContext().clauseSource,
-                  "Invalid reduction operator in REDUCTION clause."_err_en_US,
-                  ContextDirectiveAsFortran());
-            }
-          },
-          [&](const parser::ProcedureDesignator &procD) {
-            const parser::Name *name{std::get_if<parser::Name>(&procD.u)};
-            if (name && name->symbol) {
-              const SourceName &realName{name->symbol->GetUltimate().name()};
-              if (realName == "max" || realName == "min" ||
-                  realName == "iand" || realName == "ior" ||
-                  realName == "ieor") {
-                ok = true;
-              }
-            }
-            if (!ok) {
-              context_.Say(GetContext().clauseSource,
-                  "Invalid reduction identifier in REDUCTION "
-                  "clause."_err_en_US,
-                  ContextDirectiveAsFortran());
-            }
-          },
-      },
-      definedOp->u);
 
   return ok;
 }

flang/lib/Semantics/resolve-directives.cpp

@@ -522,49 +522,47 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
     const auto &objList{std::get<parser::OmpObjectList>(x.v.t)};
     ResolveOmpObjectList(objList, Symbol::Flag::OmpReduction);
 
-    auto &modifiers{OmpGetModifiers(x.v)};
-    if (!modifiers) {
-      return false;
-    }
-
-    auto createDummyProcSymbol = [&](const parser::Name *name) {
-      // If name resolution failed, create a dummy symbol
-      const auto namePair{
-          currScope().try_emplace(name->source, Attrs{}, ProcEntityDetails{})};
-      auto &newSymbol{*namePair.first->second};
-      if (context_.intrinsics().IsIntrinsic(name->ToString())) {
-        newSymbol.attrs().set(Attr::INTRINSIC);
-      }
-      name->symbol = &newSymbol;
-    };
+    if (auto &modifiers{OmpGetModifiers(x.v)}) {
+      auto createDummyProcSymbol = [&](const parser::Name *name) {
+        // If name resolution failed, create a dummy symbol
+        const auto namePair{currScope().try_emplace(
+            name->source, Attrs{}, ProcEntityDetails{})};
+        auto &newSymbol{*namePair.first->second};
+        if (context_.intrinsics().IsIntrinsic(name->ToString())) {
+          newSymbol.attrs().set(Attr::INTRINSIC);
+        }
+        name->symbol = &newSymbol;
+      };
 
-    for (auto &mod : *modifiers) {
-      if (!std::holds_alternative<parser::OmpReductionIdentifier>(mod.u)) {
-        continue;
-      }
-      auto &opr{std::get<parser::OmpReductionIdentifier>(mod.u)};
-      if (auto *procD{parser::Unwrap<parser::ProcedureDesignator>(opr.u)}) {
-        if (auto *name{parser::Unwrap<parser::Name>(procD->u)}) {
-          if (!name->symbol) {
-            if (!ResolveName(name)) {
-              createDummyProcSymbol(name);
+      for (auto &mod : *modifiers) {
+        if (!std::holds_alternative<parser::OmpReductionIdentifier>(mod.u)) {
+          continue;
+        }
+        auto &opr{std::get<parser::OmpReductionIdentifier>(mod.u)};
+        if (auto *procD{parser::Unwrap<parser::ProcedureDesignator>(opr.u)}) {
+          if (auto *name{parser::Unwrap<parser::Name>(procD->u)}) {
+            if (!name->symbol) {
+              if (!ResolveName(name)) {
+                createDummyProcSymbol(name);
+              }
             }
           }
-        }
-        if (auto *procRef{parser::Unwrap<parser::ProcComponentRef>(procD->u)}) {
-          if (!procRef->v.thing.component.symbol) {
-            if (!ResolveName(&procRef->v.thing.component)) {
-              createDummyProcSymbol(&procRef->v.thing.component);
+          if (auto *procRef{
+                  parser::Unwrap<parser::ProcComponentRef>(procD->u)}) {
+            if (!procRef->v.thing.component.symbol) {
+              if (!ResolveName(&procRef->v.thing.component)) {
+                createDummyProcSymbol(&procRef->v.thing.component);
+              }
             }
           }
         }
       }
-    }
-    using ReductionModifier = parser::OmpReductionModifier;
-    if (auto *maybeModifier{
-            OmpGetUniqueModifier<ReductionModifier>(modifiers)}) {
-      if (maybeModifier->v == ReductionModifier::Value::Inscan) {
-        ResolveOmpObjectList(objList, Symbol::Flag::OmpInScanReduction);
+      using ReductionModifier = parser::OmpReductionModifier;
+      if (auto *maybeModifier{
+              OmpGetUniqueModifier<ReductionModifier>(modifiers)}) {
+        if (maybeModifier->v == ReductionModifier::Value::Inscan) {
+          ResolveOmpObjectList(objList, Symbol::Flag::OmpInScanReduction);
+        }
       }
     }
     return false;