[X86][AVX2] Add support for combining v16i16 shuffles to VPBLENDW

llvm-svn: 298929

1 files changed, 47 insertions, 28 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index cb38a85b83b..88e09cd56f8 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -27140,43 +27140,62 @@ static bool matchBinaryPermuteVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
   }
 
   // Attempt to combine to X86ISD::BLENDI.
-  // TODO - add 16i16 support (requires lane duplication).
-  if (NumMaskElts <= 8 && ((Subtarget.hasSSE41() && MaskVT.is128BitVector()) ||
-                           (Subtarget.hasAVX() && MaskVT.is256BitVector()))) {
+  if ((NumMaskElts <= 8 && ((Subtarget.hasSSE41() && MaskVT.is128BitVector()) ||
+                            (Subtarget.hasAVX() && MaskVT.is256BitVector()))) ||
+      (MaskVT == MVT::v16i16 && Subtarget.hasAVX2())) {
     uint64_t BlendMask = 0;
     bool ForceV1Zero = false, ForceV2Zero = false;
     SmallVector<int, 8> TargetMask(Mask.begin(), Mask.end());
     if (matchVectorShuffleAsBlend(V1, V2, TargetMask, ForceV1Zero, ForceV2Zero,
                                   BlendMask)) {
-      // Determine a type compatible with X86ISD::BLENDI.
-      ShuffleVT = MaskVT;
-      if (Subtarget.hasAVX2()) {
-        if (ShuffleVT == MVT::v4i64)
-          ShuffleVT = MVT::v8i32;
-        else if (ShuffleVT == MVT::v2i64)
-          ShuffleVT = MVT::v4i32;
+      if (MaskVT == MVT::v16i16) {
+        // We can only use v16i16 PBLENDW if the lanes are repeated.
+        SmallVector<int, 8> RepeatedMask;
+        if (isRepeatedTargetShuffleMask(128, MaskVT, TargetMask,
+                                        RepeatedMask)) {
+          assert(RepeatedMask.size() == 8 &&
+                 "Repeated mask size doesn't match!");
+          PermuteImm = 0;
+          for (int i = 0; i < 8; ++i)
+            if (RepeatedMask[i] >= 8)
+              PermuteImm |= 1 << i;
+          V1 = ForceV1Zero ? getZeroVector(MaskVT, Subtarget, DAG, DL) : V1;
+          V2 = ForceV2Zero ? getZeroVector(MaskVT, Subtarget, DAG, DL) : V2;
+          Shuffle = X86ISD::BLENDI;
+          ShuffleVT = MaskVT;
+          return true;
+        }
       } else {
-        if (ShuffleVT == MVT::v2i64 || ShuffleVT == MVT::v4i32)
-          ShuffleVT = MVT::v8i16;
-        else if (ShuffleVT == MVT::v4i64)
-          ShuffleVT = MVT::v4f64;
-        else if (ShuffleVT == MVT::v8i32)
-          ShuffleVT = MVT::v8f32;
-      }
+        // Determine a type compatible with X86ISD::BLENDI.
+        ShuffleVT = MaskVT;
+        if (Subtarget.hasAVX2()) {
+          if (ShuffleVT == MVT::v4i64)
+            ShuffleVT = MVT::v8i32;
+          else if (ShuffleVT == MVT::v2i64)
+            ShuffleVT = MVT::v4i32;
+        } else {
+          if (ShuffleVT == MVT::v2i64 || ShuffleVT == MVT::v4i32)
+            ShuffleVT = MVT::v8i16;
+          else if (ShuffleVT == MVT::v4i64)
+            ShuffleVT = MVT::v4f64;
+          else if (ShuffleVT == MVT::v8i32)
+            ShuffleVT = MVT::v8f32;
+        }
 
-      V1 = ForceV1Zero ? getZeroVector(MaskVT, Subtarget, DAG, DL) : V1;
-      V2 = ForceV2Zero ? getZeroVector(MaskVT, Subtarget, DAG, DL) : V2;
+        if (!ShuffleVT.isFloatingPoint()) {
+          int Scale = EltSizeInBits / ShuffleVT.getScalarSizeInBits();
+          BlendMask =
+              scaleVectorShuffleBlendMask(BlendMask, NumMaskElts, Scale);
+          ShuffleVT = MVT::getIntegerVT(EltSizeInBits / Scale);
+          ShuffleVT = MVT::getVectorVT(ShuffleVT, NumMaskElts * Scale);
+        }
 
-      if (!ShuffleVT.isFloatingPoint()) {
-        int Scale = EltSizeInBits / ShuffleVT.getScalarSizeInBits();
-        BlendMask = scaleVectorShuffleBlendMask(BlendMask, NumMaskElts, Scale);
-        ShuffleVT = MVT::getIntegerVT(EltSizeInBits / Scale);
-        ShuffleVT = MVT::getVectorVT(ShuffleVT, NumMaskElts * Scale);
+        V1 = ForceV1Zero ? getZeroVector(MaskVT, Subtarget, DAG, DL) : V1;
+        V2 = ForceV2Zero ? getZeroVector(MaskVT, Subtarget, DAG, DL) : V2;
+        PermuteImm = (unsigned)BlendMask;
+        Shuffle = X86ISD::BLENDI;
+        return true;
       }
-
-      PermuteImm = (unsigned)BlendMask;
-      Shuffle = X86ISD::BLENDI;
-      return true;
     }
   }