[OPENMP 4.1] Codegen for ‘simd’ clause in ‘ordered’ directive.

Description.
If the simd clause is specified, the ordered regions encountered by any thread will use only a single SIMD lane to execute the ordered regions in the order of the loop iterations.
Restrictions.
An ordered construct with the simd clause is the only OpenMP construct that can appear in the simd region.

An ordered directive with ‘simd’ clause is generated as an outlined function and corresponding function call to prevent this part of code from vectorization later in backend.

llvm-svn: 248772

3 files changed, 28 insertions, 8 deletions

diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.cpp b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
index 7251bd3ef66..3b265b041d1 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -1548,21 +1548,21 @@ void CGOpenMPRuntime::emitSingleRegion(CodeGenFunction &CGF,
 
 void CGOpenMPRuntime::emitOrderedRegion(CodeGenFunction &CGF,
                                         const RegionCodeGenTy &OrderedOpGen,
-                                        SourceLocation Loc) {
+                                        SourceLocation Loc, bool IsThreads) {
   // __kmpc_ordered(ident_t *, gtid);
   // OrderedOpGen();
   // __kmpc_end_ordered(ident_t *, gtid);
   // Prepare arguments and build a call to __kmpc_ordered
-  {
-    CodeGenFunction::RunCleanupsScope Scope(CGF);
+  CodeGenFunction::RunCleanupsScope Scope(CGF);
+  if (IsThreads) {
     llvm::Value *Args[] = {emitUpdateLocation(CGF, Loc), getThreadID(CGF, Loc)};
     CGF.EmitRuntimeCall(createRuntimeFunction(OMPRTL__kmpc_ordered), Args);
     // Build a call to __kmpc_end_ordered
     CGF.EHStack.pushCleanup<CallEndCleanup<std::extent<decltype(Args)>::value>>(
         NormalAndEHCleanup, createRuntimeFunction(OMPRTL__kmpc_end_ordered),
         llvm::makeArrayRef(Args));
-    emitInlinedDirective(CGF, OMPD_ordered, OrderedOpGen);
   }
+  emitInlinedDirective(CGF, OMPD_ordered, OrderedOpGen);
 }
 
 void CGOpenMPRuntime::emitBarrierCall(CodeGenFunction &CGF, SourceLocation Loc,
diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.h b/clang/lib/CodeGen/CGOpenMPRuntime.h
index 011006a3f81..c84ea008fc7 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.h
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.h
@@ -449,7 +449,7 @@ public:
   /// ordered region.
   virtual void emitOrderedRegion(CodeGenFunction &CGF,
                                  const RegionCodeGenTy &OrderedOpGen,
-                                 SourceLocation Loc);
+                                 SourceLocation Loc, bool IsThreads);
 
   /// \brief Emit an implicit/explicit barrier for OpenMP threads.
   /// \param Kind Directive for which this implicit barrier call must be
diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index a06b0a24925..45fa610b314 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -1799,13 +1799,33 @@ void CodeGenFunction::EmitOMPFlushDirective(const OMPFlushDirective &S) {
   }(), S.getLocStart());
 }
 
+static llvm::Function *emitOutlinedOrderedFunction(CodeGenModule &CGM,
+                                                   const CapturedStmt *S) {
+  CodeGenFunction CGF(CGM, /*suppressNewContext=*/true);
+  CodeGenFunction::CGCapturedStmtInfo CapStmtInfo;
+  CGF.CapturedStmtInfo = &CapStmtInfo;
+  auto *Fn = CGF.GenerateOpenMPCapturedStmtFunction(*S);
+  Fn->addFnAttr(llvm::Attribute::NoInline);
+  return Fn;
+}
+
 void CodeGenFunction::EmitOMPOrderedDirective(const OMPOrderedDirective &S) {
   LexicalScope Scope(*this, S.getSourceRange());
-  auto &&CodeGen = [&S](CodeGenFunction &CGF) {
-    CGF.EmitStmt(cast<CapturedStmt>(S.getAssociatedStmt())->getCapturedStmt());
+  auto *C = S.getSingleClause<OMPSIMDClause>();
+  auto &&CodeGen = [&S, C, this](CodeGenFunction &CGF) {
+    if (C) {
+      auto CS = cast<CapturedStmt>(S.getAssociatedStmt());
+      llvm::SmallVector<llvm::Value *, 16> CapturedVars;
+      CGF.GenerateOpenMPCapturedVars(*CS, CapturedVars);
+      auto *OutlinedFn = emitOutlinedOrderedFunction(CGM, CS);
+      CGF.EmitNounwindRuntimeCall(OutlinedFn, CapturedVars);
+    } else {
+      CGF.EmitStmt(
+          cast<CapturedStmt>(S.getAssociatedStmt())->getCapturedStmt());
+    }
     CGF.EnsureInsertPoint();
   };
-  CGM.getOpenMPRuntime().emitOrderedRegion(*this, CodeGen, S.getLocStart());
+  CGM.getOpenMPRuntime().emitOrderedRegion(*this, CodeGen, S.getLocStart(), !C);
 }
 
 static llvm::Value *convertToScalarValue(CodeGenFunction &CGF, RValue Val,