diff --git a/lib/Target/X86/InstPrinter/X86InstComments.cpp b/lib/Target/X86/InstPrinter/X86InstComments.cpp
index 64ac5e685f7..d8a45ea9738 100644
--- a/lib/Target/X86/InstPrinter/X86InstComments.cpp
+++ b/lib/Target/X86/InstPrinter/X86InstComments.cpp
@@ -69,6 +69,28 @@ void llvm::EmitAnyX86InstComments(const MCInst *MI, raw_ostream &OS,
     DecodeMOVHLPSMask(2, ShuffleMask);
     break;
 
+  case X86::PALIGNR128rr:
+  case X86::VPALIGNR128rr:
+    Src1Name = getRegName(MI->getOperand(2).getReg());
+    // FALL THROUGH.
+  case X86::PALIGNR128rm:
+  case X86::VPALIGNR128rm:
+    Src2Name = getRegName(MI->getOperand(1).getReg());
+    DestName = getRegName(MI->getOperand(0).getReg());
+    DecodePALIGNMask(MVT::v16i8,
+                     MI->getOperand(MI->getNumOperands()-1).getImm(),
+                     ShuffleMask);
+    break;
+  case X86::VPALIGNR256rr:
+    Src1Name = getRegName(MI->getOperand(2).getReg());
+    // FALL THROUGH.
+  case X86::VPALIGNR256rm:
+    Src2Name = getRegName(MI->getOperand(1).getReg());
+    DestName = getRegName(MI->getOperand(0).getReg());
+    DecodePALIGNMask(MVT::v32i8,
+                     MI->getOperand(MI->getNumOperands()-1).getImm(),
+                     ShuffleMask);
+
   case X86::PSHUFDri:
   case X86::VPSHUFDri:
     Src1Name = getRegName(MI->getOperand(1).getReg());
diff --git a/lib/Target/X86/Utils/X86ShuffleDecode.cpp b/lib/Target/X86/Utils/X86ShuffleDecode.cpp
index 8b87c1f9c8a..9694808e641 100644
--- a/lib/Target/X86/Utils/X86ShuffleDecode.cpp
+++ b/lib/Target/X86/Utils/X86ShuffleDecode.cpp
@@ -61,6 +61,14 @@ void DecodeMOVLHPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
     ShuffleMask.push_back(NElts+i);
 }
 
+void DecodePALIGNMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
+  unsigned NumElts = VT.getVectorNumElements();
+  unsigned Offset = Imm * (VT.getVectorElementType().getSizeInBits() / 8);
+
+  for (unsigned i = 0; i != NumElts; ++i)
+    ShuffleMask.push_back((i + Offset) % (NumElts * 2));
+}
+
 /// DecodePSHUFMask - This decodes the shuffle masks for pshufd, and vpermilp*.
 /// VT indicates the type of the vector allowing it to handle different
 /// datatypes and vector widths.
diff --git a/lib/Target/X86/Utils/X86ShuffleDecode.h b/lib/Target/X86/Utils/X86ShuffleDecode.h
index 70d8171a815..69ce4432ed1 100644
--- a/lib/Target/X86/Utils/X86ShuffleDecode.h
+++ b/lib/Target/X86/Utils/X86ShuffleDecode.h
@@ -35,6 +35,8 @@ void DecodeMOVHLPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask);
 // <0,2> or <0,1,4,5>
 void DecodeMOVLHPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask);
 
+void DecodePALIGNMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask);
+
 void DecodePSHUFMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask);
 
 void DecodePSHUFHWMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask);
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 6daa9b65e6f..76ec12c740c 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -4592,6 +4592,10 @@ static bool getTargetShuffleMask(SDNode *N, MVT VT,
   case X86ISD::MOVLHPS:
     DecodeMOVLHPSMask(NumElems, Mask);
     break;
+  case X86ISD::PALIGN:
+    ImmN = N->getOperand(N->getNumOperands()-1);
+    DecodePALIGNMask(VT, cast<ConstantSDNode>(ImmN)->getZExtValue(), Mask);
+    break;
   case X86ISD::PSHUFD:
   case X86ISD::VPERMILP:
     ImmN = N->getOperand(N->getNumOperands()-1);
@@ -4635,7 +4639,6 @@ static bool getTargetShuffleMask(SDNode *N, MVT VT,
   case X86ISD::MOVLPS:
   case X86ISD::MOVSHDUP:
   case X86ISD::MOVSLDUP:
-  case X86ISD::PALIGN:
     // Not yet implemented
     return false;
   default: llvm_unreachable("unknown target shuffle node");
diff --git a/test/MC/X86/shuffle-comments.s b/test/MC/X86/shuffle-comments.s
new file mode 100644
index 00000000000..e2f84af4a0d
--- /dev/null
+++ b/test/MC/X86/shuffle-comments.s
@@ -0,0 +1,31 @@
+# RUN: llvm-mc %s -triple=x86_64-unknown-unknown | FileCheck %s
+
+palignr $8, %xmm0, %xmm1
+# CHECK: xmm1 = xmm0[8,9,10,11,12,13,14,15],xmm1[0,1,2,3,4,5,6,7]
+palignr $8, (%rax), %xmm1
+# CHECK: xmm1 = mem[8,9,10,11,12,13,14,15],xmm1[0,1,2,3,4,5,6,7]
+
+palignr $16, %xmm0, %xmm1
+# CHECK: xmm1 = xmm1[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
+palignr $16, (%rax), %xmm1
+# CHECK: xmm1 = xmm1[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
+
+palignr $0, %xmm0, %xmm1
+# CHECK: xmm1 = xmm0[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
+palignr $0, (%rax), %xmm1
+# CHECK: xmm1 = mem[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
+
+vpalignr $8, %xmm0, %xmm1, %xmm2
+# CHECK: xmm2 = xmm0[8,9,10,11,12,13,14,15],xmm1[0,1,2,3,4,5,6,7]
+vpalignr $8, (%rax), %xmm1, %xmm2
+# CHECK: xmm2 = mem[8,9,10,11,12,13,14,15],xmm1[0,1,2,3,4,5,6,7]
+
+vpalignr $16, %xmm0, %xmm1, %xmm2
+# CHECK: xmm2 = xmm1[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
+vpalignr $16, (%rax), %xmm1, %xmm2
+# CHECK: xmm2 = xmm1[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
+
+vpalignr $0, %xmm0, %xmm1, %xmm2
+# CHECK: xmm2 = xmm0[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
+vpalignr $0, (%rax), %xmm1, %xmm2
+# CHECK: xmm2 = mem[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]