Masked Load / Store Intrinsics - the CodeGen part.
I'm recommiting the codegen part of the patch.
The vectorizer part will be send to review again.

Masked Vector Load and Store Intrinsics.
Introduced new target-independent intrinsics in order to support masked vector loads and stores. The loop vectorizer optimizes loops containing conditional memory accesses by generating these intrinsics for existing targets AVX2 and AVX-512. The vectorizer asks the target about availability of masked vector loads and stores.
Added SDNodes for masked operations and lowering patterns for X86 code generator.
Examples:
<16 x i32> @llvm.masked.load.v16i32(i8* %addr, <16 x i32> %passthru, i32 4 /* align */, <16 x i1> %mask)
declare void @llvm.masked.store.v8f64(i8* %addr, <8 x double> %value, i32 4, <8 x i1> %mask)

Scalarizer for other targets (not AVX2/AVX-512) will be done in a separate patch.

http://reviews.llvm.org/D6191

llvm-svn: 223348
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index eeecbf1..c3b197e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -3617,6 +3617,70 @@
   DAG.setRoot(StoreNode);
 }
 
+void SelectionDAGBuilder::visitMaskedStore(const CallInst &I) {
+  SDLoc sdl = getCurSDLoc();
+
+  Value  *PtrOperand = I.getArgOperand(0);
+  SDValue Ptr = getValue(PtrOperand);
+  SDValue Src0 = getValue(I.getArgOperand(1));
+  SDValue Mask = getValue(I.getArgOperand(3));
+  EVT VT = Src0.getValueType();
+  unsigned Alignment = (cast<ConstantInt>(I.getArgOperand(2)))->getZExtValue();
+  if (!Alignment)
+    Alignment = DAG.getEVTAlignment(VT);
+
+  AAMDNodes AAInfo;
+  I.getAAMetadata(AAInfo);
+
+  MachineMemOperand *MMO =
+    DAG.getMachineFunction().
+    getMachineMemOperand(MachinePointerInfo(PtrOperand),
+                          MachineMemOperand::MOStore,  VT.getStoreSize(),
+                          Alignment, AAInfo);
+  SDValue StoreNode = DAG.getMaskedStore(getRoot(), sdl, Src0, Ptr, Mask, MMO);
+  DAG.setRoot(StoreNode);
+  setValue(&I, StoreNode);
+}
+
+void SelectionDAGBuilder::visitMaskedLoad(const CallInst &I) {
+  SDLoc sdl = getCurSDLoc();
+
+  Value  *PtrOperand = I.getArgOperand(0);
+  SDValue Ptr = getValue(PtrOperand);
+  SDValue Src0 = getValue(I.getArgOperand(1));
+  SDValue Mask = getValue(I.getArgOperand(3));
+
+  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+  EVT VT = TLI.getValueType(I.getType());
+  unsigned Alignment = (cast<ConstantInt>(I.getArgOperand(2)))->getZExtValue();
+  if (!Alignment)
+    Alignment = DAG.getEVTAlignment(VT);
+
+  AAMDNodes AAInfo;
+  I.getAAMetadata(AAInfo);
+  const MDNode *Ranges = I.getMetadata(LLVMContext::MD_range);
+
+  SDValue InChain = DAG.getRoot();
+  if (AA->pointsToConstantMemory(
+      AliasAnalysis::Location(PtrOperand,
+                              AA->getTypeStoreSize(I.getType()),
+                              AAInfo))) {
+    // Do not serialize (non-volatile) loads of constant memory with anything.
+    InChain = DAG.getEntryNode();
+  }
+
+  MachineMemOperand *MMO =
+    DAG.getMachineFunction().
+    getMachineMemOperand(MachinePointerInfo(PtrOperand),
+                          MachineMemOperand::MOLoad,  VT.getStoreSize(),
+                          Alignment, AAInfo, Ranges);
+
+  SDValue Load = DAG.getMaskedLoad(VT, sdl, InChain, Ptr, Mask, Src0, MMO);
+  SDValue OutChain = Load.getValue(1);
+  DAG.setRoot(OutChain);
+  setValue(&I, Load);
+}
+
 void SelectionDAGBuilder::visitAtomicCmpXchg(const AtomicCmpXchgInst &I) {
   SDLoc dl = getCurSDLoc();
   AtomicOrdering SuccessOrder = I.getSuccessOrdering();
@@ -4918,6 +4982,12 @@
     return nullptr;
   }
 
+  case Intrinsic::masked_load:
+    visitMaskedLoad(I);
+    return nullptr;
+  case Intrinsic::masked_store:
+    visitMaskedStore(I);
+    return nullptr;
   case Intrinsic::x86_mmx_pslli_w:
   case Intrinsic::x86_mmx_pslli_d:
   case Intrinsic::x86_mmx_pslli_q: