[Openmp-commits] [clang] [llvm] [openmp] [Clang][OpenMP] Add `#pragma omp flatten` loop directive + `depth` clause (PR #206977)

[Alexey Bataev via Openmp-commits]

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@@ -1380,6 +1380,74 @@ class OMPPartialClause final : public OMPClause {
   }
 };
 
+/// This represents the 'depth' clause on the '#pragma omp flatten' (and
+/// '#pragma omp fuse') loop-transformation directives.
+///
+/// \code
+/// #pragma omp flatten depth(3)
+/// \endcode
+/// In this example the 'flatten' directive has a 'depth' clause whose argument
+/// '3' specifies how many perfectly nested loops are combined into one.
+/// The argument must be a positive integer constant expression that evaluates
+/// to at most the loop nest depth of the associated loop nest.
+class OMPDepthClause final : public OMPClause {
+  friend class OMPClauseReader;
+
+  /// Location of '('.
+  SourceLocation LParenLoc;
+
+  /// The depth expression (number of loops to flatten).
+  Stmt *Depth = nullptr;
+
+  /// Build an empty clause.
+  explicit OMPDepthClause() : OMPClause(llvm::omp::OMPC_depth, {}, {}) {}
+
+  /// Set the depth expression.
+  void setDepth(Expr *E) { Depth = E; }
+
+  /// Sets the location of '('.
+  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }
+
+public:
+  /// Build an AST node for a 'depth' clause.
+  ///
+  /// \param C         Context of the AST.
+  /// \param StartLoc  Location of the 'depth' identifier.
+  /// \param LParenLoc Location of '('.
+  /// \param EndLoc    Location of ')'.
+  /// \param Depth     The depth expression.
+  static OMPDepthClause *Create(const ASTContext &C, SourceLocation StartLoc,
+                                SourceLocation LParenLoc, SourceLocation EndLoc,
+                                Expr *Depth);
+
+  /// Build an empty 'depth' AST node for deserialization.
+  ///
+  /// \param C     Context of the AST.
+  static OMPDepthClause *CreateEmpty(const ASTContext &C);
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alexey-bataev wrote:

Usually, we declare this pseudo-constructors, if the default constructor does not work =, like if we have tail allocated elements. Otherwise, just regular constructors should be good enough

https://github.com/llvm/llvm-project/pull/206977