Recommit r354363 "[X86][SSE] Generalize X86ISD::BLENDI support to more value types"

And its follow ups r354511, r354640.

A follow patch will fix the issue that caused it to be reverted.

llvm-svn: 354737

1 files changed, 40 insertions, 60 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index aa9fd6bc03a..f90a2478306 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -10482,45 +10482,24 @@ static SDValue lowerShuffleAsBlend(const SDLoc &DL, MVT VT, SDValue V1,
     V2 = getZeroVector(VT, Subtarget, DAG, DL);
 
   switch (VT.SimpleTy) {
-  case MVT::v2f64:
-  case MVT::v4f32:
-  case MVT::v4f64:
-  case MVT::v8f32:
-    return DAG.getNode(X86ISD::BLENDI, DL, VT, V1, V2,
-                       DAG.getConstant(BlendMask, DL, MVT::i8));
   case MVT::v4i64:
   case MVT::v8i32:
     assert(Subtarget.hasAVX2() && "256-bit integer blends require AVX2!");
     LLVM_FALLTHROUGH;
+  case MVT::v4f64:
+  case MVT::v8f32:
+    assert(Subtarget.hasAVX() && "256-bit float blends require AVX!");
+    LLVM_FALLTHROUGH;
+  case MVT::v2f64:
   case MVT::v2i64:
+  case MVT::v4f32:
   case MVT::v4i32:
-    // If we have AVX2 it is faster to use VPBLENDD when the shuffle fits into
-    // that instruction.
-    if (Subtarget.hasAVX2()) {
-      // Scale the blend by the number of 32-bit dwords per element.
-      int Scale =  VT.getScalarSizeInBits() / 32;
-      BlendMask = scaleVectorShuffleBlendMask(BlendMask, Mask.size(), Scale);
-      MVT BlendVT = VT.getSizeInBits() > 128 ? MVT::v8i32 : MVT::v4i32;
-      V1 = DAG.getBitcast(BlendVT, V1);
-      V2 = DAG.getBitcast(BlendVT, V2);
-      return DAG.getBitcast(
-          VT, DAG.getNode(X86ISD::BLENDI, DL, BlendVT, V1, V2,
-                          DAG.getConstant(BlendMask, DL, MVT::i8)));
-    }
-    LLVM_FALLTHROUGH;
-  case MVT::v8i16: {
-    // For integer shuffles we need to expand the mask and cast the inputs to
-    // v8i16s prior to blending.
-    int Scale = 8 / VT.getVectorNumElements();
-    BlendMask = scaleVectorShuffleBlendMask(BlendMask, Mask.size(), Scale);
-    V1 = DAG.getBitcast(MVT::v8i16, V1);
-    V2 = DAG.getBitcast(MVT::v8i16, V2);
-    return DAG.getBitcast(VT,
-                          DAG.getNode(X86ISD::BLENDI, DL, MVT::v8i16, V1, V2,
-                                      DAG.getConstant(BlendMask, DL, MVT::i8)));
-  }
+  case MVT::v8i16:
+    assert(Subtarget.hasSSE41() && "128-bit blends require SSE41!");
+    return DAG.getNode(X86ISD::BLENDI, DL, VT, V1, V2,
+                       DAG.getConstant(BlendMask, DL, MVT::i8));
   case MVT::v16i16: {
-    assert(Subtarget.hasAVX2() && "256-bit integer blends require AVX2!");
+    assert(Subtarget.hasAVX2() && "v16i16 blends require AVX2!");
     SmallVector<int, 8> RepeatedMask;
     if (is128BitLaneRepeatedShuffleMask(MVT::v16i16, Mask, RepeatedMask)) {
       // We can lower these with PBLENDW which is mirrored across 128-bit lanes.
@@ -10548,10 +10527,11 @@ static SDValue lowerShuffleAsBlend(const SDLoc &DL, MVT VT, SDValue V1,
     }
     LLVM_FALLTHROUGH;
   }
-  case MVT::v16i8:
-  case MVT::v32i8: {
-    assert((VT.is128BitVector() || Subtarget.hasAVX2()) &&
-           "256-bit byte-blends require AVX2 support!");
+  case MVT::v32i8:
+    assert(Subtarget.hasAVX2() && "256-bit byte-blends require AVX2!");
+    LLVM_FALLTHROUGH;
+  case MVT::v16i8: {
+    assert(Subtarget.hasSSE41() && "128-bit byte-blends require SSE41!");
 
     // Attempt to lower to a bitmask if we can. VPAND is faster than VPBLENDVB.
     if (SDValue Masked = lowerShuffleAsBitMask(DL, VT, V1, V2, Mask, Zeroable,
@@ -31055,34 +31035,11 @@ static bool matchBinaryPermuteShuffle(
           return true;
         }
       } else {
-        // 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;
-        }
-
-        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;
+        ShuffleVT = MaskVT;
         return true;
       }
     }
@@ -32239,6 +32196,29 @@ static SDValue combineTargetShuffle(SDValue N, SelectionDAG &DAG,
 
     return SDValue();
   }
+  case X86ISD::BLENDI: {
+    SDValue N0 = N.getOperand(0);
+    SDValue N1 = N.getOperand(1);
+
+    // blend(bitcast(x),bitcast(y)) -> bitcast(blend(x,y)) to narrower types.
+    // TODO: Handle MVT::v16i16 repeated blend mask.
+    if (N0.getOpcode() == ISD::BITCAST && N1.getOpcode() == ISD::BITCAST &&
+        N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
+      MVT SrcVT = N0.getOperand(0).getSimpleValueType();
+      if ((VT.getScalarSizeInBits() % SrcVT.getScalarSizeInBits()) == 0 &&
+          SrcVT.getScalarSizeInBits() >= 32) {
+        unsigned Mask = N.getConstantOperandVal(2);
+        unsigned Size = VT.getVectorNumElements();
+        unsigned Scale = VT.getScalarSizeInBits() / SrcVT.getScalarSizeInBits();
+        unsigned ScaleMask = scaleVectorShuffleBlendMask(Mask, Size, Scale);
+        return DAG.getBitcast(
+            VT, DAG.getNode(X86ISD::BLENDI, DL, SrcVT, N0.getOperand(0),
+                            N1.getOperand(0),
+                            DAG.getConstant(ScaleMask, DL, MVT::i8)));
+      }
+    }
+    return SDValue();
+  }
   case X86ISD::PSHUFD:
   case X86ISD::PSHUFLW:
   case X86ISD::PSHUFHW: