X86: Decode PALIGN operands so I don't have to do it in my head.

llvm-svn: 173572
diff --git a/llvm/lib/Target/X86/InstPrinter/X86InstComments.cpp b/llvm/lib/Target/X86/InstPrinter/X86InstComments.cpp
index 64ac5e6..d8a45ea 100644
--- a/llvm/lib/Target/X86/InstPrinter/X86InstComments.cpp
+++ b/llvm/lib/Target/X86/InstPrinter/X86InstComments.cpp
@@ -69,6 +69,28 @@
     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/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
index 8b87c1f..9694808 100644
--- a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
+++ b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp
@@ -61,6 +61,14 @@
     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/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
index 70d8171..69ce443 100644
--- a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
+++ b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
@@ -35,6 +35,8 @@
 // <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/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 6daa9b6..76ec12c 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -4592,6 +4592,10 @@
   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 @@
   case X86ISD::MOVLPS:
   case X86ISD::MOVSHDUP:
   case X86ISD::MOVSLDUP:
-  case X86ISD::PALIGN:
     // Not yet implemented
     return false;
   default: llvm_unreachable("unknown target shuffle node");