[OPENMP][NVPTX]Mark __kmpc_barrier functions as convergent.

__kmpc_barrier runtime functions must be marked as convergent to prevent
some dangerous optimizations. Also, for NVPTX target all barriers must
be emitted as simple barriers.

llvm-svn: 348271

1 files changed, 25 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
index 2bc98f6178b..cf814a4b203 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
@@ -96,6 +96,8 @@ enum OpenMPRTLFunctionNVPTX {
   OMPRTL_NVPTX__kmpc_get_team_static_memory,
   /// Call to void __kmpc_restore_team_static_memory(int16_t is_shared);
   OMPRTL_NVPTX__kmpc_restore_team_static_memory,
+  // Call to void __kmpc_barrier(ident_t *loc, kmp_int32 global_tid);
+  OMPRTL__kmpc_barrier,
 };
 
 /// Pre(post)-action for different OpenMP constructs specialized for NVPTX.
@@ -1824,6 +1826,15 @@ CGOpenMPRuntimeNVPTX::createNVPTXRuntimeFunction(unsigned Function) {
         CGM.CreateRuntimeFunction(FnTy, "__kmpc_restore_team_static_memory");
     break;
   }
+  case OMPRTL__kmpc_barrier: {
+    // Build void __kmpc_barrier(ident_t *loc, kmp_int32 global_tid);
+    llvm::Type *TypeParams[] = {getIdentTyPointerTy(), CGM.Int32Ty};
+    auto *FnTy =
+        llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, /*Name*/ "__kmpc_barrier");
+    cast<llvm::Function>(RTLFn)->addFnAttr(llvm::Attribute::Convergent);
+    break;
+  }
   }
   return RTLFn;
 }
@@ -2676,6 +2687,20 @@ void CGOpenMPRuntimeNVPTX::emitSPMDParallelCall(
   }
 }
 
+void CGOpenMPRuntimeNVPTX::emitBarrierCall(CodeGenFunction &CGF,
+                                           SourceLocation Loc,
+                                           OpenMPDirectiveKind Kind, bool,
+                                           bool) {
+  // Always emit simple barriers!
+  if (!CGF.HaveInsertPoint())
+    return;
+  // Build call __kmpc_cancel_barrier(loc, thread_id);
+  unsigned Flags = getDefaultFlagsForBarriers(Kind);
+  llvm::Value *Args[] = {emitUpdateLocation(CGF, Loc, Flags),
+                         getThreadID(CGF, Loc)};
+  CGF.EmitRuntimeCall(createNVPTXRuntimeFunction(OMPRTL__kmpc_barrier), Args);
+}
+
 void CGOpenMPRuntimeNVPTX::emitCriticalRegion(
     CodeGenFunction &CGF, StringRef CriticalName,
     const RegionCodeGenTy &CriticalOpGen, SourceLocation Loc,