Lower AVX v4i64->v4i32 truncate to one shuffle.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202996 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 12 deletions

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 5058fb9b7a..951d3ded99 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -9134,24 +9134,14 @@ SDValue X86TargetLowering::LowerTRUNCATE(SDValue Op, SelectionDAG &DAG) const {
                          DAG.getIntPtrConstant(0));
     }
 
-    // On AVX, v4i64 -> v4i32 becomes a sequence that uses PSHUFD and MOVLHPS.
     SDValue OpLo = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, MVT::v2i64, In,
                                DAG.getIntPtrConstant(0));
     SDValue OpHi = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, MVT::v2i64, In,
                                DAG.getIntPtrConstant(2));
-
     OpLo = DAG.getNode(ISD::BITCAST, DL, MVT::v4i32, OpLo);
     OpHi = DAG.getNode(ISD::BITCAST, DL, MVT::v4i32, OpHi);
-
-    // The PSHUFD mask:
-    static const int ShufMask1[] = {0, 2, 0, 0};
-    SDValue Undef = DAG.getUNDEF(VT);
-    OpLo = DAG.getVectorShuffle(VT, DL, OpLo, Undef, ShufMask1);
-    OpHi = DAG.getVectorShuffle(VT, DL, OpHi, Undef, ShufMask1);
-
-    // The MOVLHPS mask:
-    static const int ShufMask2[] = {0, 1, 4, 5};
-    return DAG.getVectorShuffle(VT, DL, OpLo, OpHi, ShufMask2);
+    static const int ShufMask[] = {0, 2, 4, 6};
+    return DAG.getVectorShuffle(VT, DL, OpLo, OpHi, ShufMask);
   }
 
   if ((VT == MVT::v8i16) && (InVT == MVT::v8i32)) {