[OpenMP] Initial implementation of code generation for pragma 'distribute parallel for' on host

https://reviews.llvm.org/D29508

This patch makes the following additions:

1. It abstracts away loop bound generation code from procedures associated with pragma 'for' and loops in general, in such a way that the same procedures can be used for 'distribute parallel for' without the need for a full re-implementation.
2. It implements code generation for 'distribute parallel for' and adds regression tests. It includes tests for clauses.

It is important to notice that most of the clauses are implemented as part of existing procedures. For instance, firstprivate is already implemented for 'distribute' and 'for' as separate pragmas. As the implementation of 'distribute parallel for' is based on the same procedures, then we automatically obtain implementation for such clauses without the need to add new code. However, this requires regression tests that verify correctness of produced code.

Looking forward to comments.

llvm-svn: 301223

1 files changed, 80 insertions, 16 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index fa72019eb08..1ded824ba5b 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -175,6 +175,25 @@ public:
   // because of jumps.
   VarBypassDetector Bypasses;
 
+  // CodeGen lambda for loops and support for ordered clause
+  typedef llvm::function_ref<void(CodeGenFunction &, const OMPLoopDirective &,
+                                  JumpDest)>
+      CodeGenLoopTy;
+  typedef llvm::function_ref<void(CodeGenFunction &, SourceLocation,
+                                  const unsigned, const bool)>
+      CodeGenOrderedTy;
+
+  // Codegen lambda for loop bounds in worksharing loop constructs
+  typedef llvm::function_ref<std::pair<LValue, LValue>(
+      CodeGenFunction &, const OMPExecutableDirective &S)>
+      CodeGenLoopBoundsTy;
+
+  // Codegen lambda for loop bounds in dispatch-based loop implementation
+  typedef llvm::function_ref<std::pair<llvm::Value *, llvm::Value *>(
+      CodeGenFunction &, const OMPExecutableDirective &S, Address LB,
+      Address UB)>
+      CodeGenDispatchBoundsTy;
+
   /// \brief CGBuilder insert helper. This function is called after an
   /// instruction is created using Builder.
   void InsertHelper(llvm::Instruction *I, const llvm::Twine &Name,
@@ -2756,7 +2775,6 @@ public:
   void EmitOMPTaskLoopDirective(const OMPTaskLoopDirective &S);
   void EmitOMPTaskLoopSimdDirective(const OMPTaskLoopSimdDirective &S);
   void EmitOMPDistributeDirective(const OMPDistributeDirective &S);
-  void EmitOMPDistributeLoop(const OMPDistributeDirective &S);
   void EmitOMPDistributeParallelForDirective(
       const OMPDistributeParallelForDirective &S);
   void EmitOMPDistributeParallelForSimdDirective(
@@ -2813,32 +2831,78 @@ public:
   void EmitOMPPrivateLoopCounters(const OMPLoopDirective &S,
                                   OMPPrivateScope &LoopScope);
 
+  /// Helper for the OpenMP loop directives.
+  void EmitOMPLoopBody(const OMPLoopDirective &D, JumpDest LoopExit);
+
+  /// \brief Emit code for the worksharing loop-based directive.
+  /// \return true, if this construct has any lastprivate clause, false -
+  /// otherwise.
+  bool EmitOMPWorksharingLoop(const OMPLoopDirective &S, Expr *EUB,
+                              const CodeGenLoopBoundsTy &CodeGenLoopBounds,
+                              const CodeGenDispatchBoundsTy &CGDispatchBounds);
+
 private:
   /// Helpers for blocks
   llvm::Value *EmitBlockLiteral(const CGBlockInfo &Info);
 
   /// Helpers for the OpenMP loop directives.
-  void EmitOMPLoopBody(const OMPLoopDirective &D, JumpDest LoopExit);
   void EmitOMPSimdInit(const OMPLoopDirective &D, bool IsMonotonic = false);
   void EmitOMPSimdFinal(
       const OMPLoopDirective &D,
       const llvm::function_ref<llvm::Value *(CodeGenFunction &)> &CondGen);
-  /// \brief Emit code for the worksharing loop-based directive.
-  /// \return true, if this construct has any lastprivate clause, false -
-  /// otherwise.
-  bool EmitOMPWorksharingLoop(const OMPLoopDirective &S);
-  void EmitOMPOuterLoop(bool IsMonotonic, bool DynamicOrOrdered,
-      const OMPLoopDirective &S, OMPPrivateScope &LoopScope, bool Ordered,
-      Address LB, Address UB, Address ST, Address IL, llvm::Value *Chunk);
+
+  void EmitOMPDistributeLoop(const OMPLoopDirective &S,
+                             const CodeGenLoopTy &CodeGenLoop, Expr *IncExpr);
+
+  /// struct with the values to be passed to the OpenMP loop-related functions
+  struct OMPLoopArguments {
+    /// loop lower bound
+    Address LB = Address::invalid();
+    /// loop upper bound
+    Address UB = Address::invalid();
+    /// loop stride
+    Address ST = Address::invalid();
+    /// isLastIteration argument for runtime functions
+    Address IL = Address::invalid();
+    /// Chunk value generated by sema
+    llvm::Value *Chunk = nullptr;
+    /// EnsureUpperBound
+    Expr *EUB = nullptr;
+    /// IncrementExpression
+    Expr *IncExpr = nullptr;
+    /// Loop initialization
+    Expr *Init = nullptr;
+    /// Loop exit condition
+    Expr *Cond = nullptr;
+    /// Update of LB after a whole chunk has been executed
+    Expr *NextLB = nullptr;
+    /// Update of UB after a whole chunk has been executed
+    Expr *NextUB = nullptr;
+    OMPLoopArguments() = default;
+    OMPLoopArguments(Address LB, Address UB, Address ST, Address IL,
+                     llvm::Value *Chunk = nullptr, Expr *EUB = nullptr,
+                     Expr *IncExpr = nullptr, Expr *Init = nullptr,
+                     Expr *Cond = nullptr, Expr *NextLB = nullptr,
+                     Expr *NextUB = nullptr)
+        : LB(LB), UB(UB), ST(ST), IL(IL), Chunk(Chunk), EUB(EUB),
+          IncExpr(IncExpr), Init(Init), Cond(Cond), NextLB(NextLB),
+          NextUB(NextUB) {}
+  };
+  void EmitOMPOuterLoop(bool DynamicOrOrdered, bool IsMonotonic,
+                        const OMPLoopDirective &S, OMPPrivateScope &LoopScope,
+                        const OMPLoopArguments &LoopArgs,
+                        const CodeGenLoopTy &CodeGenLoop,
+                        const CodeGenOrderedTy &CodeGenOrdered);
   void EmitOMPForOuterLoop(const OpenMPScheduleTy &ScheduleKind,
                            bool IsMonotonic, const OMPLoopDirective &S,
-                           OMPPrivateScope &LoopScope, bool Ordered, Address LB,
-                           Address UB, Address ST, Address IL,
-                           llvm::Value *Chunk);
-  void EmitOMPDistributeOuterLoop(
-      OpenMPDistScheduleClauseKind ScheduleKind,
-      const OMPDistributeDirective &S, OMPPrivateScope &LoopScope,
-      Address LB, Address UB, Address ST, Address IL, llvm::Value *Chunk);
+                           OMPPrivateScope &LoopScope, bool Ordered,
+                           const OMPLoopArguments &LoopArgs,
+                           const CodeGenDispatchBoundsTy &CGDispatchBounds);
+  void EmitOMPDistributeOuterLoop(OpenMPDistScheduleClauseKind ScheduleKind,
+                                  const OMPLoopDirective &S,
+                                  OMPPrivateScope &LoopScope,
+                                  const OMPLoopArguments &LoopArgs,
+                                  const CodeGenLoopTy &CodeGenLoopContent);
   /// \brief Emit code for sections directive.
   void EmitSections(const OMPExecutableDirective &S);