Revert "[Flang][OpenMP] Add semantic check for OpenMP Private, Firstprivate and Lastprivate clauses."

This reverts commit a2ca6bb.

D93213 performs some checks to ensure that variables that appear in
statement functions are not in privatisation clauses. The point at
which this check is currently performed, there can be misparses that
cause more constructs to be identified as statement functions. This
can lead to various kinds of errors, hence reverting.

This revert hopefully fixes:
llvm/llvm-project#54477
llvm/llvm-project#54161
llvm/llvm-project#54163

Reviewed By: shraiysh

Differential Revision: https://reviews.llvm.org/D122650

Author: kiranchandramohan

flang/lib/Semantics/resolve-directives.cpp

@@ -279,18 +279,6 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
     return true;
   }
 
-  bool Pre(const parser::StmtFunctionStmt &x) {
-    const auto &parsedExpr{std::get<parser::Scalar<parser::Expr>>(x.t)};
-    if (const auto *expr{GetExpr(parsedExpr)}) {
-      for (const Symbol &symbol : evaluate::CollectSymbols(*expr)) {
-        if (!IsStmtFunctionDummy(symbol)) {
-          stmtFunctionExprSymbols_.insert(symbol.GetUltimate());
-        }
-      }
-    }
-    return true;
-  }
-
   bool Pre(const parser::OpenMPBlockConstruct &);
   void Post(const parser::OpenMPBlockConstruct &);
 
@@ -530,7 +518,7 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
   void CheckDataCopyingClause(
       const parser::Name &, const Symbol &, Symbol::Flag);
   void CheckAssocLoopLevel(std::int64_t level, const parser::OmpClause *clause);
-  void CheckPrivateDSAObject(
+  void CheckObjectInNamelist(
       const parser::Name &, const Symbol &, Symbol::Flag);
   void CheckSourceLabel(const parser::Label &);
   void CheckLabelContext(const parser::CharBlock, const parser::CharBlock,
@@ -1585,7 +1573,7 @@ void OmpAttributeVisitor::ResolveOmpObject(
                     CheckMultipleAppearances(*name, *symbol, ompFlag);
                   }
                   if (privateDataSharingAttributeFlags.test(ompFlag)) {
-                    CheckPrivateDSAObject(*name, *symbol, ompFlag);
+                    CheckObjectInNamelist(*name, *symbol, ompFlag);
                   }
 
                   if (ompFlag == Symbol::Flag::OmpAllocate) {
@@ -1779,7 +1767,7 @@ void OmpAttributeVisitor::CheckDataCopyingClause(
   }
 }
 
-void OmpAttributeVisitor::CheckPrivateDSAObject(
+void OmpAttributeVisitor::CheckObjectInNamelist(
     const parser::Name &name, const Symbol &symbol, Symbol::Flag ompFlag) {
   const auto &ultimateSymbol{symbol.GetUltimate()};
   llvm::StringRef clauseName{"PRIVATE"};
@@ -1794,14 +1782,6 @@ void OmpAttributeVisitor::CheckPrivateDSAObject(
         "Variable '%s' in NAMELIST cannot be in a %s clause"_err_en_US,
         name.ToString(), clauseName.str());
   }
-
-  if (stmtFunctionExprSymbols_.find(ultimateSymbol) !=
-      stmtFunctionExprSymbols_.end()) {
-    context_.Say(name.source,
-        "Variable '%s' in STATEMENT FUNCTION expression cannot be in a "
-        "%s clause"_err_en_US,
-        name.ToString(), clauseName.str());
-  }
 }
 
 void OmpAttributeVisitor::CheckSourceLabel(const parser::Label &label) {