1 files changed, 38 insertions, 8 deletions
diff --git a/lib/Target/X86/X86TargetTransformInfo.cpp b/lib/Target/X86/X86TargetTransformInfo.cpp
index 299f9a581b..9fa911967e 100644
--- a/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -402,17 +402,47 @@ unsigned X86TTI::getArithmeticInstrCost(unsigned Opcode, Type *Ty,
 
 unsigned X86TTI::getShuffleCost(ShuffleKind Kind, Type *Tp, int Index,
                                 Type *SubTp) const {
-  // We only estimate the cost of reverse shuffles.
-  if (Kind != SK_Reverse)
+  // We only estimate the cost of reverse and alternate shuffles.
+  if (Kind != SK_Reverse && Kind != SK_Alternate)
     return TargetTransformInfo::getShuffleCost(Kind, Tp, Index, SubTp);
 
-  std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Tp);
-  unsigned Cost = 1;
-  if (LT.second.getSizeInBits() > 128)
-    Cost = 3; // Extract + insert + copy.
+  if (Kind == SK_Reverse) {
+    std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Tp);
+    unsigned Cost = 1;
+    if (LT.second.getSizeInBits() > 128)
+      Cost = 3; // Extract + insert + copy.
 
-  // Multiple by the number of parts.
-  return Cost * LT.first;
+    // Multiple by the number of parts.
+    return Cost * LT.first;
+  }
+
+  if (Kind == SK_Alternate) {
+    static const CostTblEntry<MVT::SimpleValueType> X86AltShuffleTbl[] = {
+        // Alt shuffle cost table for X86. Cost is the number of instructions
+        // required to create the shuffled vector.
+
+        {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1},
+        {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1},
+        {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1},
+
+        {ISD::VECTOR_SHUFFLE, MVT::v2i32, 2},
+        {ISD::VECTOR_SHUFFLE, MVT::v4i32, 2},
+        {ISD::VECTOR_SHUFFLE, MVT::v4f32, 2},
+
+        {ISD::VECTOR_SHUFFLE, MVT::v4i16, 8},
+        {ISD::VECTOR_SHUFFLE, MVT::v8i16, 8},
+
+        {ISD::VECTOR_SHUFFLE, MVT::v16i8, 49}};
+
+    std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Tp);
+
+    int Idx = CostTableLookup(X86AltShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second);
+    if (Idx == -1)
+      return TargetTransformInfo::getShuffleCost(Kind, Tp, Index, SubTp);
+    return LT.first * X86AltShuffleTbl[Idx].Cost;
+  }
+
+  return TargetTransformInfo::getShuffleCost(Kind, Tp, Index, SubTp);
 }
 
 unsigned X86TTI::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src) const {