IR: add a second ordering operand to cmpxhg for failure

The syntax for "cmpxchg" should now look something like:

	cmpxchg i32* %addr, i32 42, i32 3 acquire monotonic

where the second ordering argument gives the required semantics in the case
that no exchange takes place. It should be no stronger than the first ordering
constraint and cannot be either "release" or "acq_rel" (since no store will
have taken place).

rdar://problem/15996804

llvm-svn: 203559
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 2dcfbb5..6297774 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -2878,6 +2878,7 @@
                                  Node->getOperand(1), Zero, Zero,
                                  cast<AtomicSDNode>(Node)->getMemOperand(),
                                  cast<AtomicSDNode>(Node)->getOrdering(),
+                                 cast<AtomicSDNode>(Node)->getOrdering(),
                                  cast<AtomicSDNode>(Node)->getSynchScope());
     Results.push_back(Swap.getValue(0));
     Results.push_back(Swap.getValue(1));
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index cd7c496..18b2376 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -193,10 +193,10 @@
 SDValue DAGTypeLegalizer::PromoteIntRes_Atomic2(AtomicSDNode *N) {
   SDValue Op2 = GetPromotedInteger(N->getOperand(2));
   SDValue Op3 = GetPromotedInteger(N->getOperand(3));
-  SDValue Res = DAG.getAtomic(N->getOpcode(), SDLoc(N),
-                              N->getMemoryVT(), N->getChain(), N->getBasePtr(),
-                              Op2, Op3, N->getMemOperand(), N->getOrdering(),
-                              N->getSynchScope());
+  SDValue Res = DAG.getAtomic(N->getOpcode(), SDLoc(N), N->getMemoryVT(),
+                              N->getChain(), N->getBasePtr(), Op2, Op3,
+                              N->getMemOperand(), N->getSuccessOrdering(),
+                              N->getFailureOrdering(), N->getSynchScope());
   // Legalized the chain result - switch anything that used the old chain to
   // use the new one.
   ReplaceValueWith(SDValue(N, 1), Res.getValue(1));
@@ -2448,6 +2448,7 @@
                                N->getOperand(1), Zero, Zero,
                                cast<AtomicSDNode>(N)->getMemOperand(),
                                cast<AtomicSDNode>(N)->getOrdering(),
+                               cast<AtomicSDNode>(N)->getOrdering(),
                                cast<AtomicSDNode>(N)->getSynchScope());
   ReplaceValueWith(SDValue(N, 0), Swap.getValue(0));
   ReplaceValueWith(SDValue(N, 1), Swap.getValue(1));
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 9a9062a..43a02fe 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -4223,9 +4223,10 @@
 }
 
 SDValue SelectionDAG::getAtomic(unsigned Opcode, SDLoc dl, EVT MemVT,
-                                SDVTList VTList, SDValue* Ops, unsigned NumOps,
+                                SDVTList VTList, SDValue *Ops, unsigned NumOps,
                                 MachineMemOperand *MMO,
-                                AtomicOrdering Ordering,
+                                AtomicOrdering SuccessOrdering,
+                                AtomicOrdering FailureOrdering,
                                 SynchronizationScope SynchScope) {
   FoldingSetNodeID ID;
   ID.AddInteger(MemVT.getRawBits());
@@ -4247,17 +4248,28 @@
   SDNode *N = new (NodeAllocator) AtomicSDNode(Opcode, dl.getIROrder(),
                                                dl.getDebugLoc(), VTList, MemVT,
                                                Ops, DynOps, NumOps, MMO,
-                                               Ordering, SynchScope);
+                                               SuccessOrdering, FailureOrdering,
+                                               SynchScope);
   CSEMap.InsertNode(N, IP);
   AllNodes.push_back(N);
   return SDValue(N, 0);
 }
 
 SDValue SelectionDAG::getAtomic(unsigned Opcode, SDLoc dl, EVT MemVT,
+                                SDVTList VTList, SDValue *Ops, unsigned NumOps,
+                                MachineMemOperand *MMO,
+                                AtomicOrdering Ordering,
+                                SynchronizationScope SynchScope) {
+  return getAtomic(Opcode, dl, MemVT, VTList, Ops, NumOps, MMO, Ordering,
+                   Ordering, SynchScope);
+}
+
+SDValue SelectionDAG::getAtomic(unsigned Opcode, SDLoc dl, EVT MemVT,
                                 SDValue Chain, SDValue Ptr, SDValue Cmp,
                                 SDValue Swp, MachinePointerInfo PtrInfo,
                                 unsigned Alignment,
-                                AtomicOrdering Ordering,
+                                AtomicOrdering SuccessOrdering,
+                                AtomicOrdering FailureOrdering,
                                 SynchronizationScope SynchScope) {
   if (Alignment == 0)  // Ensure that codegen never sees alignment 0
     Alignment = getEVTAlignment(MemVT);
@@ -4278,14 +4290,15 @@
     MF.getMachineMemOperand(PtrInfo, Flags, MemVT.getStoreSize(), Alignment);
 
   return getAtomic(Opcode, dl, MemVT, Chain, Ptr, Cmp, Swp, MMO,
-                   Ordering, SynchScope);
+                   SuccessOrdering, FailureOrdering, SynchScope);
 }
 
 SDValue SelectionDAG::getAtomic(unsigned Opcode, SDLoc dl, EVT MemVT,
                                 SDValue Chain,
                                 SDValue Ptr, SDValue Cmp,
                                 SDValue Swp, MachineMemOperand *MMO,
-                                AtomicOrdering Ordering,
+                                AtomicOrdering SuccessOrdering,
+                                AtomicOrdering FailureOrdering,
                                 SynchronizationScope SynchScope) {
   assert(Opcode == ISD::ATOMIC_CMP_SWAP && "Invalid Atomic Op");
   assert(Cmp.getValueType() == Swp.getValueType() && "Invalid Atomic Op Types");
@@ -4294,7 +4307,8 @@
 
   SDVTList VTs = getVTList(VT, MVT::Other);
   SDValue Ops[] = {Chain, Ptr, Cmp, Swp};
-  return getAtomic(Opcode, dl, MemVT, VTs, Ops, 4, MMO, Ordering, SynchScope);
+  return getAtomic(Opcode, dl, MemVT, VTs, Ops, 4, MMO, SuccessOrdering,
+                   FailureOrdering, SynchScope);
 }
 
 SDValue SelectionDAG::getAtomic(unsigned Opcode, SDLoc dl, EVT MemVT,
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 13daba08..b60e780 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -3605,14 +3605,15 @@
 
 void SelectionDAGBuilder::visitAtomicCmpXchg(const AtomicCmpXchgInst &I) {
   SDLoc dl = getCurSDLoc();
-  AtomicOrdering Order = I.getOrdering();
+  AtomicOrdering SuccessOrder = I.getSuccessOrdering();
+  AtomicOrdering FailureOrder = I.getFailureOrdering();
   SynchronizationScope Scope = I.getSynchScope();
 
   SDValue InChain = getRoot();
 
   const TargetLowering *TLI = TM.getTargetLowering();
   if (TLI->getInsertFencesForAtomic())
-    InChain = InsertFenceForAtomic(InChain, Order, Scope, true, dl,
+    InChain = InsertFenceForAtomic(InChain, SuccessOrder, Scope, true, dl,
                                    DAG, *TLI);
 
   SDValue L =
@@ -3623,13 +3624,14 @@
                   getValue(I.getCompareOperand()),
                   getValue(I.getNewValOperand()),
                   MachinePointerInfo(I.getPointerOperand()), 0 /* Alignment */,
-                  TLI->getInsertFencesForAtomic() ? Monotonic : Order,
+                  TLI->getInsertFencesForAtomic() ? Monotonic : SuccessOrder,
+                  TLI->getInsertFencesForAtomic() ? Monotonic : FailureOrder,
                   Scope);
 
   SDValue OutChain = L.getValue(1);
 
   if (TLI->getInsertFencesForAtomic())
-    OutChain = InsertFenceForAtomic(OutChain, Order, Scope, false, dl,
+    OutChain = InsertFenceForAtomic(OutChain, SuccessOrder, Scope, false, dl,
                                     DAG, *TLI);
 
   setValue(&I, L);