Add XCore support for ATOMIC_FENCE.

ATOMIC_FENCE is lowered to a compiler barrier which is codegen only. There
is no need to emit an instructions since the XCore provides sequential
consistency.

Original patch by Richard Osborne

llvm-svn: 194464

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/Target/XCore/XCoreISelLowering.cpp b/llvm/lib/Target/XCore/XCoreISelLowering.cpp
index 489f0a7244c..149652ff733 100644
--- a/llvm/lib/Target/XCore/XCoreISelLowering.cpp
+++ b/llvm/lib/Target/XCore/XCoreISelLowering.cpp
@@ -59,6 +59,7 @@ getTargetNodeName(unsigned Opcode) const
     case XCoreISD::CRC8              : return "XCoreISD::CRC8";
     case XCoreISD::BR_JT             : return "XCoreISD::BR_JT";
     case XCoreISD::BR_JT32           : return "XCoreISD::BR_JT32";
+    case XCoreISD::MEMBARRIER        : return "XCoreISD::MEMBARRIER";
     default                          : return NULL;
   }
 }
@@ -148,6 +149,9 @@ XCoreTargetLowering::XCoreTargetLowering(XCoreTargetMachine &XTM)
   setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Expand);
 
+  // Atomic operations
+  setOperationAction(ISD::ATOMIC_FENCE, MVT::Other, Custom);
+
   // TRAMPOLINE is custom lowered.
   setOperationAction(ISD::INIT_TRAMPOLINE, MVT::Other, Custom);
   setOperationAction(ISD::ADJUST_TRAMPOLINE, MVT::Other, Custom);
@@ -206,6 +210,7 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::INIT_TRAMPOLINE:    return LowerINIT_TRAMPOLINE(Op, DAG);
   case ISD::ADJUST_TRAMPOLINE:  return LowerADJUST_TRAMPOLINE(Op, DAG);
   case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG);
+  case ISD::ATOMIC_FENCE:       return LowerATOMIC_FENCE(Op, DAG);
   default:
     llvm_unreachable("unimplemented operand");
   }
@@ -847,6 +852,12 @@ LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG) const {
   return SDValue();
 }
 
+SDValue XCoreTargetLowering::
+LowerATOMIC_FENCE(SDValue Op, SelectionDAG &DAG) const {
+  SDLoc DL(Op);
+  return DAG.getNode(XCoreISD::MEMBARRIER, DL, MVT::Other, Op.getOperand(0));
+}
+
 //===----------------------------------------------------------------------===//
 //                      Calling Convention Implementation
 //===----------------------------------------------------------------------===//