Index: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
@@ -9383,6 +9383,30 @@
                      DAG.getConstant(PermMask, DL, MVT::i8));
 }
 
+/// \brief Handle lowering 4-lane 128-bit shuffles.
+static SDValue lowerV4X128VectorShuffle(SDLoc DL, MVT VT, SDValue V1,
+                                        SDValue V2, ArrayRef<int> WidenedMask,
+                                        SelectionDAG &DAG) {
+
+  assert(WidenedMask.size() == 4 && "Unexpected mask size for 128bit shuffle!");
+  // form a 128-bit permutation.
+  // convert the 64-bit shuffle mask selection values into 128-bit selection
+  // bits defined by a vshuf64x2 instruction's immediate control byte.
+  unsigned PermMask = 0, Imm = 0;
+
+  for (int i = 0, Size = WidenedMask.size(); i < Size; ++i) {
+    if(WidenedMask[i] == SM_SentinelZero)
+      return SDValue();
+
+    // use first element in place of undef musk
+    Imm = (WidenedMask[i] == SM_SentinelUndef) ? 0 : WidenedMask[i];
+    PermMask |= (Imm % 4) << (i * 2);
+  }
+
+  return DAG.getNode(X86ISD::SHUF128, DL, VT, V1, V2,
+                     DAG.getConstant(PermMask, DL, MVT::i8));
+}
+
 /// \brief Lower a vector shuffle by first fixing the 128-bit lanes and then
 /// shuffling each lane.
 ///
@@ -10176,6 +10200,10 @@
   ArrayRef<int> Mask = SVOp->getMask();
   assert(Mask.size() == 8 && "Unexpected mask size for v8 shuffle!");
 
+  SmallVector<int, 4> WidenedMask;
+  if (canWidenShuffleElements(Mask, WidenedMask))
+    if(SDValue Op = lowerV4X128VectorShuffle(DL, VT, V1, V2, WidenedMask, DAG))
+      return Op;
   // X86 has dedicated unpack instructions that can handle specific blend
   // operations: UNPCKH and UNPCKL.
   if (isShuffleEquivalent(V1, V2, Mask, {0, 8, 2, 10, 4, 12, 6, 14}))
Index: llvm/trunk/test/CodeGen/X86/avx512-shuffle.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/avx512-shuffle.ll
+++ llvm/trunk/test/CodeGen/X86/avx512-shuffle.ll
@@ -116,10 +116,10 @@
  ret <16 x i32> %b
 }
 ; CHECK-LABEL: test16
-; CHECK: valignq $2, %zmm0, %zmm1
+; CHECK: valignq $3, %zmm0, %zmm1
 ; CHECK: ret
 define <8 x double> @test16(<8 x double> %a, <8 x double> %b) nounwind {
-  %c = shufflevector <8 x double> %a, <8 x double> %b, <8 x i32> <i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9>
+  %c = shufflevector <8 x double> %a, <8 x double> %b, <8 x i32> <i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10>
   ret <8 x double> %c
 }
 
@@ -252,6 +252,62 @@
   ret <8 x double> %c
 }
 
+; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=knl | FileCheck %s
+define <8 x double> @test_vshuff64x2_512(<8 x double> %x, <8 x double> %x1) nounwind {
+; CHECK-LABEL: test_vshuff64x2_512:
+; CHECK:       ## BB#0:
+; CHECK-NEXT:    vshuff64x2 $136, %zmm0, %zmm0, %zmm0
+; CHECK-NEXT:    retq
+  %res = shufflevector <8 x double> %x, <8 x double> %x1, <8 x i32> <i32 0, i32 1, i32 4, i32 5, i32 0, i32 1,  i32 4, i32 5>
+  ret <8 x double> %res
+}
+
+define <8 x double> @test_vshuff64x2_512_mask(<8 x double> %x, <8 x double> %x1, <8 x i1> %mask) nounwind {
+; CHECK-LABEL: test_vshuff64x2_512_mask:
+; CHECK:       ## BB#0:
+; CHECK-NEXT:    vpmovsxwq %xmm2, %zmm1
+; CHECK-NEXT:    vpandq {{.*}}(%rip){1to8}, %zmm1, %zmm1
+; CHECK-NEXT:    vptestmq %zmm1, %zmm1, %k1
+; CHECK-NEXT:    vshuff64x2 $136, %zmm0, %zmm0, %zmm0 {%k1} {z}
+; CHECK-NEXT:    retq
+  %y = shufflevector <8 x double> %x, <8 x double> %x1, <8 x i32> <i32 0, i32 1, i32 4, i32 5, i32 0, i32 1,  i32 4, i32 5>
+  %res = select <8 x i1> %mask, <8 x double> %y, <8 x double> zeroinitializer
+  ret <8 x double> %res
+}
+
+define <8 x i64> @test_vshufi64x2_512_mask(<8 x i64> %x, <8 x i64> %x1, <8 x i1> %mask) nounwind {
+; CHECK-LABEL: test_vshufi64x2_512_mask:
+; CHECK:       ## BB#0:
+; CHECK-NEXT:    vpmovsxwq %xmm2, %zmm1
+; CHECK-NEXT:    vpandq {{.*}}(%rip){1to8}, %zmm1, %zmm1
+; CHECK-NEXT:    vptestmq %zmm1, %zmm1, %k1
+; CHECK-NEXT:    vshufi64x2 $168, %zmm0, %zmm0, %zmm0 {%k1}
+; CHECK-NEXT:    retq
+  %y = shufflevector <8 x i64> %x, <8 x i64> %x1, <8 x i32> <i32 0, i32 1, i32 4, i32 5, i32 4, i32 5,  i32 4, i32 5>
+  %res = select <8 x i1> %mask, <8 x i64> %y, <8 x i64> %x
+  ret <8 x i64> %res
+}
+
+define <8 x double> @test_vshuff64x2_512_mem(<8 x double> %x, <8 x double> *%ptr) nounwind {
+; CHECK-LABEL: test_vshuff64x2_512_mem:
+; CHECK:       ## BB#0:
+; CHECK-NEXT:    vshuff64x2 $40, %zmm0, %zmm0, %zmm0
+; CHECK-NEXT:    retq
+  %x1   = load <8 x double>,<8 x double> *%ptr,align 1
+  %res = shufflevector <8 x double> %x, <8 x double> %x1, <8 x i32> <i32 0, i32 1, i32 4, i32 5, i32 4, i32 5,  i32 0, i32 1>
+  ret <8 x double> %res
+}
+
+define <16 x float> @test_vshuff32x4_512_mem(<16 x float> %x, <16 x float> *%ptr) nounwind {
+; CHECK-LABEL: test_vshuff32x4_512_mem:
+; CHECK:       ## BB#0:
+; CHECK-NEXT:    vshuff64x2 $20, %zmm0, %zmm0, %zmm0
+; CHECK-NEXT:    retq
+  %x1   = load <16 x float>,<16 x float> *%ptr,align 1
+  %res = shufflevector <16 x float> %x, <16 x float> %x1, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 4, i32 5, i32 6, i32 7, i32 0, i32 1, i32 2, i32 3>
+  ret <16 x float> %res
+}
+
 define <16 x i32> @test_align_v16i32_rr(<16 x i32> %a, <16 x i32> %b) nounwind {
 ; CHECK-LABEL: test_align_v16i32_rr:
 ; CHECK:       ## BB#0:
Index: llvm/trunk/test/CodeGen/X86/vector-shuffle-512-v8.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/vector-shuffle-512-v8.ll
+++ llvm/trunk/test/CodeGen/X86/vector-shuffle-512-v8.ll
@@ -88,7 +88,7 @@
 define <8 x double> @shuffle_v8f64_01014545(<8 x double> %a, <8 x double> %b) {
 ; ALL-LABEL: shuffle_v8f64_01014545:
 ; ALL:       # BB#0:
-; ALL-NEXT:    vpermpd $68, %zmm0, %zmm0
+; ALL-NEXT:    vshuff64x2 $160, %zmm0, %zmm0, %zmm0
 ; ALL-NEXT:    retq
   %shuffle = shufflevector <8 x double> %a, <8 x double> %b, <8 x i32> <i32 0, i32 1, i32 0, i32 1, i32 4, i32 5, i32 4, i32 5>
   ret <8 x double> %shuffle
@@ -650,7 +650,7 @@
 define <8 x i64> @shuffle_v8i64_01014545(<8 x i64> %a, <8 x i64> %b) {
 ; ALL-LABEL: shuffle_v8i64_01014545:
 ; ALL:       # BB#0:
-; ALL-NEXT:    vpermq $68, %zmm0, %zmm0
+; ALL-NEXT:    vshufi64x2 $160, %zmm0, %zmm0, %zmm0
 ; ALL-NEXT:    retq
   %shuffle = shufflevector <8 x i64> %a, <8 x i64> %b, <8 x i32> <i32 0, i32 1, i32 0, i32 1, i32 4, i32 5, i32 4, i32 5>
   ret <8 x i64> %shuffle