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/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index c7d3d149..ba6e4ce 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -551,7 +551,8 @@
   IIT_ANYPTR = 26,
   IIT_V1   = 27,
   IIT_VARARG = 28,
-  IIT_HALF_VEC_ARG = 29
+  IIT_HALF_VEC_ARG = 29,
+  IIT_SAME_VEC_WIDTH_ARG = 30
 };
 
 
@@ -659,6 +660,12 @@
                                              ArgInfo));
     return;
   }
+  case IIT_SAME_VEC_WIDTH_ARG: {
+    unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
+    OutputTable.push_back(IITDescriptor::get(IITDescriptor::SameVecWidthArgument,
+                                             ArgInfo));
+    return;
+  }
   case IIT_EMPTYSTRUCT:
     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
     return;
@@ -766,7 +773,14 @@
   case IITDescriptor::HalfVecArgument:
     return VectorType::getHalfElementsVectorType(cast<VectorType>(
                                                   Tys[D.getArgumentNumber()]));
-  }
+  case IITDescriptor::SameVecWidthArgument:
+    Type *EltTy = DecodeFixedType(Infos, Tys, Context);
+    Type *Ty = Tys[D.getArgumentNumber()];
+    if (VectorType *VTy = dyn_cast<VectorType>(Ty)) {
+      return VectorType::get(EltTy, VTy->getNumElements());
+    }
+    llvm_unreachable("unhandled");
+ }
   llvm_unreachable("unhandled");
 }