r343618 - [OpenMP][NVPTX] Simplify codegen for orphaned parallel, NFCI.

Jonas Hahnfeld via cfe-commits cfe-commits at lists.llvm.org
Tue Oct 2 12:12:54 PDT 2018


Author: hahnfeld
Date: Tue Oct  2 12:12:54 2018
New Revision: 343618

URL: http://llvm.org/viewvc/llvm-project?rev=343618&view=rev
Log:
[OpenMP][NVPTX] Simplify codegen for orphaned parallel, NFCI.

Worker threads fork off to the compiler generated worker function
directly after entering the kernel function. Hence, there is no
need to check whether the current thread is the master if we are
outside of a parallel region (neither SPMD nor parallel_level > 0).

Differential Revision: https://reviews.llvm.org/D52732

Modified:
    cfe/trunk/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
    cfe/trunk/test/OpenMP/nvptx_target_codegen.cpp

Modified: cfe/trunk/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp?rev=343618&r1=343617&r2=343618&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp Tue Oct  2 12:12:54 2018
@@ -2233,30 +2233,24 @@ void CGOpenMPRuntimeNVPTX::emitNonSPMDPa
     Work.emplace_back(WFn);
   };
 
-  auto &&LNParallelGen = [this, Loc, &SeqGen, &L0ParallelGen, &CodeGen,
-                          &ThreadIDAddr](CodeGenFunction &CGF,
-                                         PrePostActionTy &Action) {
-    RegionCodeGenTy RCG(CodeGen);
+  auto &&LNParallelGen = [this, Loc, &SeqGen, &L0ParallelGen](
+                             CodeGenFunction &CGF, PrePostActionTy &Action) {
     if (IsInParallelRegion) {
       SeqGen(CGF, Action);
     } else if (IsInTargetMasterThreadRegion) {
       L0ParallelGen(CGF, Action);
-    } else if (getExecutionMode() == CGOpenMPRuntimeNVPTX::EM_NonSPMD) {
-      RCG(CGF);
     } else {
       // Check for master and then parallelism:
       // if (__kmpc_is_spmd_exec_mode() || __kmpc_parallel_level(loc, gtid)) {
-      //  Serialized execution.
-      // } else if (master) {
-      //   Worker call.
+      //   Serialized execution.
       // } else {
-      //   Outlined function call.
+      //   Worker call.
       // }
       CGBuilderTy &Bld = CGF.Builder;
       llvm::BasicBlock *ExitBB = CGF.createBasicBlock(".exit");
       llvm::BasicBlock *SeqBB = CGF.createBasicBlock(".sequential");
       llvm::BasicBlock *ParallelCheckBB = CGF.createBasicBlock(".parcheck");
-      llvm::BasicBlock *MasterCheckBB = CGF.createBasicBlock(".mastercheck");
+      llvm::BasicBlock *MasterBB = CGF.createBasicBlock(".master");
       llvm::Value *IsSPMD = Bld.CreateIsNotNull(CGF.EmitNounwindRuntimeCall(
           createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_is_spmd_exec_mode)));
       Bld.CreateCondBr(IsSPMD, SeqBB, ParallelCheckBB);
@@ -2269,29 +2263,17 @@ void CGOpenMPRuntimeNVPTX::emitNonSPMDPa
           createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_parallel_level),
           {RTLoc, ThreadID});
       llvm::Value *Res = Bld.CreateIsNotNull(PL);
-      Bld.CreateCondBr(Res, SeqBB, MasterCheckBB);
+      Bld.CreateCondBr(Res, SeqBB, MasterBB);
       CGF.EmitBlock(SeqBB);
       SeqGen(CGF, Action);
       CGF.EmitBranch(ExitBB);
       // There is no need to emit line number for unconditional branch.
       (void)ApplyDebugLocation::CreateEmpty(CGF);
-      CGF.EmitBlock(MasterCheckBB);
-      llvm::BasicBlock *MasterThenBB = CGF.createBasicBlock("master.then");
-      llvm::BasicBlock *ElseBlock = CGF.createBasicBlock("omp_if.else");
-      llvm::Value *IsMaster =
-          Bld.CreateICmpEQ(getNVPTXThreadID(CGF), getMasterThreadID(CGF));
-      Bld.CreateCondBr(IsMaster, MasterThenBB, ElseBlock);
-      CGF.EmitBlock(MasterThenBB);
+      CGF.EmitBlock(MasterBB);
       L0ParallelGen(CGF, Action);
       CGF.EmitBranch(ExitBB);
       // There is no need to emit line number for unconditional branch.
       (void)ApplyDebugLocation::CreateEmpty(CGF);
-      CGF.EmitBlock(ElseBlock);
-      // In the worker need to use the real thread id.
-      ThreadIDAddr = emitThreadIDAddress(CGF, Loc);
-      RCG(CGF);
-      // There is no need to emit line number for unconditional branch.
-      (void)ApplyDebugLocation::CreateEmpty(CGF);
       // Emit the continuation block for code after the if.
       CGF.EmitBlock(ExitBB, /*IsFinished=*/true);
     }

Modified: cfe/trunk/test/OpenMP/nvptx_target_codegen.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/OpenMP/nvptx_target_codegen.cpp?rev=343618&r1=343617&r2=343618&view=diff
==============================================================================
--- cfe/trunk/test/OpenMP/nvptx_target_codegen.cpp (original)
+++ cfe/trunk/test/OpenMP/nvptx_target_codegen.cpp Tue Oct  2 12:12:54 2018
@@ -557,7 +557,6 @@ int baz(int f, double &a) {
   // CHECK: [[STACK:%.+]] = alloca [[GLOBAL_ST:%.+]],
   // CHECK: [[ZERO_ADDR:%.+]] = alloca i32,
   // CHECK: [[GTID:%.+]] = call i32 @__kmpc_global_thread_num(%struct.ident_t*
-  // CHECK: [[GTID_ADDR:%.+]] = alloca i32,
   // CHECK: store i32 0, i32* [[ZERO_ADDR]]
   // CHECK: [[RES:%.+]] = call i8 @__kmpc_is_spmd_exec_mode()
   // CHECK: [[IS_SPMD:%.+]] = icmp ne i8 [[RES]], 0
@@ -583,9 +582,6 @@ int baz(int f, double &a) {
   // CHECK: call void @__kmpc_end_serialized_parallel(%struct.ident_t* @{{.+}}, i32 [[GTID]])
   // CHECK: br label
 
-  // CHECK: icmp eq i32
-  // CHECK: br i1
-
   // CHECK: call void @__kmpc_kernel_prepare_parallel(i8* bitcast (void (i16, i32)* @{{.+}} to i8*), i16 1)
   // CHECK: call void @__kmpc_begin_sharing_variables(i8*** [[SHARED_PTR:%.+]], i{{64|32}} 2)
   // CHECK: [[SHARED:%.+]] = load i8**, i8*** [[SHARED_PTR]],
@@ -597,10 +593,6 @@ int baz(int f, double &a) {
   // CHECK: call void @__kmpc_end_sharing_variables()
   // CHECK: br label
 
-  // CHECK: store i32 [[GTID]], i32* [[GTID_ADDR]],
-  // CHECK: call void [[OUTLINED]](i32* [[GTID_ADDR]], i32* [[ZERO_ADDR]], i32* [[F_PTR]], double* %{{.+}})
-  // CHECK: br label
-
   // CHECK: [[RES:%.+]] = load i32, i32* [[F_PTR]],
   // CHECK: store i32 [[RES]], i32* [[RET:%.+]],
   // CHECK: br i1 [[IS_SPMD]], label




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