[llvm] r342645 - [X86][SSE] Remove UNPCKL(SHUFFLE)->UNPCKH custom combine

[Simon Pilgrim via llvm-commits]

Author: rksimon
Date: Thu Sep 20 06:10:22 2018
New Revision: 342645

URL: http://llvm.org/viewvc/llvm-project?rev=342645&view=rev
Log:
[X86][SSE] Remove UNPCKL(SHUFFLE)->UNPCKH custom combine

This can be achieved more generally by combineX86ShufflesRecursively.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=342645&r1=342644&r2=342645&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Thu Sep 20 06:10:22 2018
@@ -31087,40 +31087,6 @@ static SDValue combineTargetShuffle(SDVa
     Mask = getPSHUFShuffleMask(N);
     assert(Mask.size() == 4);
     break;
-  case X86ISD::UNPCKL: {
-    // Combine X86ISD::UNPCKL and ISD::VECTOR_SHUFFLE into X86ISD::UNPCKH, in
-    // which X86ISD::UNPCKL has a ISD::UNDEF operand, and ISD::VECTOR_SHUFFLE
-    // moves upper half elements into the lower half part. For example:
-    //
-    // t2: v16i8 = vector_shuffle<8,9,10,11,12,13,14,15,u,u,u,u,u,u,u,u> t1,
-    //     undef:v16i8
-    // t3: v16i8 = X86ISD::UNPCKL undef:v16i8, t2
-    //
-    // will be combined to:
-    //
-    // t3: v16i8 = X86ISD::UNPCKH undef:v16i8, t1
-
-    // This is only for 128-bit vectors. From SSE4.1 onward this combine may not
-    // happen due to advanced instructions.
-    if (!VT.is128BitVector())
-      return SDValue();
-
-    auto Op0 = N.getOperand(0);
-    auto Op1 = N.getOperand(1);
-    if (Op0.isUndef() && Op1.getOpcode() == ISD::VECTOR_SHUFFLE) {
-      ArrayRef<int> Mask = cast<ShuffleVectorSDNode>(Op1.getNode())->getMask();
-
-      unsigned NumElts = VT.getVectorNumElements();
-      SmallVector<int, 8> ExpectedMask(NumElts, -1);
-      std::iota(ExpectedMask.begin(), ExpectedMask.begin() + NumElts / 2,
-                NumElts / 2);
-
-      auto ShufOp = Op1.getOperand(0);
-      if (isShuffleEquivalent(Op1, ShufOp, Mask, ExpectedMask))
-        return DAG.getNode(X86ISD::UNPCKH, DL, VT, N.getOperand(0), ShufOp);
-    }
-    return SDValue();
-  }
   case X86ISD::MOVSD:
   case X86ISD::MOVSS: {
     SDValue N0 = N.getOperand(0);