[OPENMP][NVPTX]Emit default locations with the correct Exec|Runtime

modes.

If the region is inside target|teams|distribute region, we can emit the
locations with the correct info for execution mode and runtime mode.
Patch adds this ability to the NVPTX codegen to help the optimizer to
produce better code.

llvm-svn: 347583

2 files changed, 47 insertions, 15 deletions

diff --git a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
index 60fbf668114..3bd88126356 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
@@ -148,19 +148,35 @@ public:
 /// a target region. The appropriate mode (SPMD|NON-SPMD) is set on entry
 /// to the target region and used by containing directives such as 'parallel'
 /// to emit optimized code.
-class ExecutionModeRAII {
+class ExecutionRuntimeModesRAII {
 private:
-  CGOpenMPRuntimeNVPTX::ExecutionMode SavedMode;
-  CGOpenMPRuntimeNVPTX::ExecutionMode &Mode;
+  CGOpenMPRuntimeNVPTX::ExecutionMode SavedExecMode =
+      CGOpenMPRuntimeNVPTX::EM_Unknown;
+  CGOpenMPRuntimeNVPTX::ExecutionMode &ExecMode;
+  bool SavedRuntimeMode = false;
+  bool *RuntimeMode = nullptr;
 
 public:
-  ExecutionModeRAII(CGOpenMPRuntimeNVPTX::ExecutionMode &Mode, bool IsSPMD)
-      : Mode(Mode) {
-    SavedMode = Mode;
-    Mode = IsSPMD ? CGOpenMPRuntimeNVPTX::EM_SPMD
-                  : CGOpenMPRuntimeNVPTX::EM_NonSPMD;
+  /// Constructor for Non-SPMD mode.
+  ExecutionRuntimeModesRAII(CGOpenMPRuntimeNVPTX::ExecutionMode &ExecMode)
+      : ExecMode(ExecMode) {
+    SavedExecMode = ExecMode;
+    ExecMode = CGOpenMPRuntimeNVPTX::EM_NonSPMD;
+  }
+  /// Constructor for SPMD mode.
+  ExecutionRuntimeModesRAII(CGOpenMPRuntimeNVPTX::ExecutionMode &ExecMode,
+                            bool &RuntimeMode, bool FullRuntimeMode)
+      : ExecMode(ExecMode), RuntimeMode(&RuntimeMode) {
+    SavedExecMode = ExecMode;
+    SavedRuntimeMode = RuntimeMode;
+    ExecMode = CGOpenMPRuntimeNVPTX::EM_SPMD;
+    RuntimeMode = FullRuntimeMode;
+  }
+  ~ExecutionRuntimeModesRAII() {
+    ExecMode = SavedExecMode;
+    if (RuntimeMode)
+      *RuntimeMode = SavedRuntimeMode;
   }
-  ~ExecutionModeRAII() { Mode = SavedMode; }
 };
 
 /// GPU Configuration:  This information can be derived from cuda registers,
@@ -1187,7 +1203,7 @@ void CGOpenMPRuntimeNVPTX::emitNonSPMDKernel(const OMPExecutableDirective &D,
                                              llvm::Constant *&OutlinedFnID,
                                              bool IsOffloadEntry,
                                              const RegionCodeGenTy &CodeGen) {
-  ExecutionModeRAII ModeRAII(CurrentExecutionMode, /*IsSPMD=*/false);
+  ExecutionRuntimeModesRAII ModeRAII(CurrentExecutionMode);
   EntryFunctionState EST;
   WorkerFunctionState WST(CGM, D.getBeginLoc());
   Work.clear();
@@ -1319,7 +1335,10 @@ void CGOpenMPRuntimeNVPTX::emitSPMDKernel(const OMPExecutableDirective &D,
                                           llvm::Constant *&OutlinedFnID,
                                           bool IsOffloadEntry,
                                           const RegionCodeGenTy &CodeGen) {
-  ExecutionModeRAII ModeRAII(CurrentExecutionMode, /*IsSPMD=*/true);
+  ExecutionRuntimeModesRAII ModeRAII(
+      CurrentExecutionMode, RequiresFullRuntime,
+      CGM.getLangOpts().OpenMPCUDAForceFullRuntime ||
+          !supportsLightweightRuntime(CGM.getContext(), D));
   EntryFunctionState EST;
 
   // Emit target region as a standalone region.
@@ -1370,9 +1389,6 @@ void CGOpenMPRuntimeNVPTX::emitSPMDEntryHeader(
   llvm::BasicBlock *ExecuteBB = CGF.createBasicBlock(".execute");
   EST.ExitBB = CGF.createBasicBlock(".exit");
 
-  // Initialize the OMP state in the runtime; called by all active threads.
-  bool RequiresFullRuntime = CGM.getLangOpts().OpenMPCUDAForceFullRuntime ||
-                             !supportsLightweightRuntime(CGF.getContext(), D);
   llvm::Value *Args[] = {getThreadLimit(CGF, /*IsInSPMDExecutionMode=*/true),
                          /*RequiresOMPRuntime=*/
                          Bld.getInt16(RequiresFullRuntime ? 1 : 0),
@@ -1919,7 +1935,18 @@ static const ModeFlagsTy UndefinedMode =
 } // anonymous namespace
 
 unsigned CGOpenMPRuntimeNVPTX::getDefaultLocationReserved2Flags() const {
-  return UndefinedMode;
+  switch (getExecutionMode()) {
+  case EM_SPMD:
+    if (requiresFullRuntime())
+      return KMP_IDENT_SPMD_MODE & (~KMP_IDENT_SIMPLE_RT_MODE);
+    return KMP_IDENT_SPMD_MODE | KMP_IDENT_SIMPLE_RT_MODE;
+  case EM_NonSPMD:
+    assert(requiresFullRuntime() && "Expected full runtime.");
+    return (~KMP_IDENT_SPMD_MODE) & (~KMP_IDENT_SIMPLE_RT_MODE);
+  case EM_Unknown:
+    return UndefinedMode;
+  }
+  llvm_unreachable("Unknown flags are requested.");
 }
 
 CGOpenMPRuntimeNVPTX::CGOpenMPRuntimeNVPTX(CodeGenModule &CGM)
diff --git a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.h b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.h
index b03ff782d75..8ba2759c8b3 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.h
+++ b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.h
@@ -56,6 +56,8 @@ private:
 
   ExecutionMode getExecutionMode() const;
 
+  bool requiresFullRuntime() const { return RequiresFullRuntime; }
+
   /// Emit the worker function for the current target region.
   void emitWorkerFunction(WorkerFunctionState &WST);
 
@@ -378,6 +380,9 @@ private:
   /// to emit optimized code.
   ExecutionMode CurrentExecutionMode = EM_Unknown;
 
+  /// Check if the full runtime is required (default - yes).
+  bool RequiresFullRuntime = true;
+
   /// true if we're emitting the code for the target region and next parallel
   /// region is L0 for sure.
   bool IsInTargetMasterThreadRegion = false;