Fix PR15296

- Move SRA/SRL/SHL lowering support from DAG combination to DAG lowering
  to support extended 256-bit integer in AVX but not AVX2.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177478 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 245 insertions, 119 deletions

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index d62cebc823..23cfd6d72f 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -11595,6 +11595,188 @@ static SDValue LowerScalarImmediateShift(SDValue Op, SelectionDAG &DAG,
     }
   }
 
+  // Special case in 32-bit mode, where i64 is expanded into high and low parts.
+  if (!Subtarget->is64Bit() &&
+      (VT == MVT::v2i64 || (Subtarget->hasInt256() && VT == MVT::v4i64)) &&
+      Amt.getOpcode() == ISD::BITCAST &&
+      Amt.getOperand(0).getOpcode() == ISD::BUILD_VECTOR) {
+    Amt = Amt.getOperand(0);
+    unsigned Ratio = Amt.getValueType().getVectorNumElements() /
+                     VT.getVectorNumElements();
+    unsigned RatioInLog2 = Log2_32_Ceil(Ratio);
+    uint64_t ShiftAmt = 0;
+    for (unsigned i = 0; i != Ratio; ++i) {
+      ConstantSDNode *C = dyn_cast<ConstantSDNode>(Amt.getOperand(i));
+      if (C == 0)
+        return SDValue();
+      // 6 == Log2(64)
+      ShiftAmt |= C->getZExtValue() << (i * (1 << (6 - RatioInLog2)));
+    }
+    // Check remaining shift amounts.
+    for (unsigned i = Ratio; i != Amt.getNumOperands(); i += Ratio) {
+      uint64_t ShAmt = 0;
+      for (unsigned j = 0; j != Ratio; ++j) {
+        ConstantSDNode *C =
+          dyn_cast<ConstantSDNode>(Amt.getOperand(i + j));
+        if (C == 0)
+          return SDValue();
+        // 6 == Log2(64)
+        ShAmt |= C->getZExtValue() << (j * (1 << (6 - RatioInLog2)));
+      }
+      if (ShAmt != ShiftAmt)
+        return SDValue();
+    }
+    switch (Op.getOpcode()) {
+    default:
+      llvm_unreachable("Unknown shift opcode!");
+    case ISD::SHL:
+      return DAG.getNode(X86ISD::VSHLI, dl, VT, R,
+                         DAG.getConstant(ShiftAmt, MVT::i32));
+    case ISD::SRL:
+      return DAG.getNode(X86ISD::VSRLI, dl, VT, R,
+                         DAG.getConstant(ShiftAmt, MVT::i32));
+    case ISD::SRA:
+      return DAG.getNode(X86ISD::VSRAI, dl, VT, R,
+                         DAG.getConstant(ShiftAmt, MVT::i32));
+    }
+  }
+
+  return SDValue();
+}
+
+static SDValue LowerScalarVariableShift(SDValue Op, SelectionDAG &DAG,
+                                        const X86Subtarget* Subtarget) {
+  EVT VT = Op.getValueType();
+  DebugLoc dl = Op.getDebugLoc();
+  SDValue R = Op.getOperand(0);
+  SDValue Amt = Op.getOperand(1);
+
+  if ((VT == MVT::v2i64 && Op.getOpcode() != ISD::SRA) ||
+      VT == MVT::v4i32 || VT == MVT::v8i16 ||
+      (Subtarget->hasInt256() &&
+       ((VT == MVT::v4i64 && Op.getOpcode() != ISD::SRA) ||
+        VT == MVT::v8i32 || VT == MVT::v16i16))) {
+    SDValue BaseShAmt;
+    EVT EltVT = VT.getVectorElementType();
+
+    if (Amt.getOpcode() == ISD::BUILD_VECTOR) {
+      unsigned NumElts = VT.getVectorNumElements();
+      unsigned i, j;
+      for (i = 0; i != NumElts; ++i) {
+        if (Amt.getOperand(i).getOpcode() == ISD::UNDEF)
+          continue;
+        break;
+      }
+      for (j = i; j != NumElts; ++j) {
+        SDValue Arg = Amt.getOperand(j);
+        if (Arg.getOpcode() == ISD::UNDEF) continue;
+        if (Arg != Amt.getOperand(i))
+          break;
+      }
+      if (i != NumElts && j == NumElts)
+        BaseShAmt = Amt.getOperand(i);
+    } else {
+      if (Amt.getOpcode() == ISD::EXTRACT_SUBVECTOR)
+        Amt = Amt.getOperand(0);
+      if (Amt.getOpcode() == ISD::VECTOR_SHUFFLE &&
+               cast<ShuffleVectorSDNode>(Amt)->isSplat()) {
+        SDValue InVec = Amt.getOperand(0);
+        if (InVec.getOpcode() == ISD::BUILD_VECTOR) {
+          unsigned NumElts = InVec.getValueType().getVectorNumElements();
+          unsigned i = 0;
+          for (; i != NumElts; ++i) {
+            SDValue Arg = InVec.getOperand(i);
+            if (Arg.getOpcode() == ISD::UNDEF) continue;
+            BaseShAmt = Arg;
+            break;
+          }
+        } else if (InVec.getOpcode() == ISD::INSERT_VECTOR_ELT) {
+           if (ConstantSDNode *C =
+               dyn_cast<ConstantSDNode>(InVec.getOperand(2))) {
+             unsigned SplatIdx =
+               cast<ShuffleVectorSDNode>(Amt)->getSplatIndex();
+             if (C->getZExtValue() == SplatIdx)
+               BaseShAmt = InVec.getOperand(1);
+           }
+        }
+        if (BaseShAmt.getNode() == 0)
+          BaseShAmt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, EltVT, Amt,
+                                  DAG.getIntPtrConstant(0));
+      }
+    }
+
+    if (BaseShAmt.getNode()) {
+      if (EltVT.bitsGT(MVT::i32))
+        BaseShAmt = DAG.getNode(ISD::TRUNCATE, dl, MVT::i32, BaseShAmt);
+      else if (EltVT.bitsLT(MVT::i32))
+        BaseShAmt = DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i32, BaseShAmt);
+
+      switch (Op.getOpcode()) {
+      default:
+        llvm_unreachable("Unknown shift opcode!");
+      case ISD::SHL:
+        switch (VT.getSimpleVT().SimpleTy) {
+        default: return SDValue();
+        case MVT::v2i64:
+        case MVT::v4i32:
+        case MVT::v8i16:
+        case MVT::v4i64:
+        case MVT::v8i32:
+        case MVT::v16i16:
+          return getTargetVShiftNode(X86ISD::VSHLI, dl, VT, R, BaseShAmt, DAG);
+        }
+      case ISD::SRA:
+        switch (VT.getSimpleVT().SimpleTy) {
+        default: return SDValue();
+        case MVT::v4i32:
+        case MVT::v8i16:
+        case MVT::v8i32:
+        case MVT::v16i16:
+          return getTargetVShiftNode(X86ISD::VSRAI, dl, VT, R, BaseShAmt, DAG);
+        }
+      case ISD::SRL:
+        switch (VT.getSimpleVT().SimpleTy) {
+        default: return SDValue();
+        case MVT::v2i64:
+        case MVT::v4i32:
+        case MVT::v8i16:
+        case MVT::v4i64:
+        case MVT::v8i32:
+        case MVT::v16i16:
+          return getTargetVShiftNode(X86ISD::VSRLI, dl, VT, R, BaseShAmt, DAG);
+        }
+      }
+    }
+  }
+
+  // Special case in 32-bit mode, where i64 is expanded into high and low parts.
+  if (!Subtarget->is64Bit() &&
+      (VT == MVT::v2i64 || (Subtarget->hasInt256() && VT == MVT::v4i64)) &&
+      Amt.getOpcode() == ISD::BITCAST &&
+      Amt.getOperand(0).getOpcode() == ISD::BUILD_VECTOR) {
+    Amt = Amt.getOperand(0);
+    unsigned Ratio = Amt.getValueType().getVectorNumElements() /
+                     VT.getVectorNumElements();
+    std::vector<SDValue> Vals(Ratio);
+    for (unsigned i = 0; i != Ratio; ++i)
+      Vals[i] = Amt.getOperand(i);
+    for (unsigned i = Ratio; i != Amt.getNumOperands(); i += Ratio) {
+      for (unsigned j = 0; j != Ratio; ++j)
+        if (Vals[j] != Amt.getOperand(i + j))
+          return SDValue();
+    }
+    switch (Op.getOpcode()) {
+    default:
+      llvm_unreachable("Unknown shift opcode!");
+    case ISD::SHL:
+      return DAG.getNode(X86ISD::VSHL, dl, VT, R, Op.getOperand(1));
+    case ISD::SRL:
+      return DAG.getNode(X86ISD::VSRL, dl, VT, R, Op.getOperand(1));
+    case ISD::SRA:
+      return DAG.getNode(X86ISD::VSRA, dl, VT, R, Op.getOperand(1));
+    }
+  }
+
   return SDValue();
 }
 
@@ -11613,6 +11795,10 @@ SDValue X86TargetLowering::LowerShift(SDValue Op, SelectionDAG &DAG) const {
   if (V.getNode())
     return V;
 
+  V = LowerScalarVariableShift(Op, DAG, Subtarget);
+  if (V.getNode())
+      return V;
+
   // AVX2 has VPSLLV/VPSRAV/VPSRLV.
   if (Subtarget->hasInt256()) {
     if (Op.getOpcode() == ISD::SRL &&
@@ -15951,124 +16137,12 @@ static SDValue PerformSHLCombine(SDNode *N, SelectionDAG &DAG) {
 static SDValue PerformShiftCombine(SDNode* N, SelectionDAG &DAG,
                                    TargetLowering::DAGCombinerInfo &DCI,
                                    const X86Subtarget *Subtarget) {
-  EVT VT = N->getValueType(0);
   if (N->getOpcode() == ISD::SHL) {
     SDValue V = PerformSHLCombine(N, DAG);
     if (V.getNode()) return V;
   }
 
-  // On X86 with SSE2 support, we can transform this to a vector shift if
-  // all elements are shifted by the same amount.  We can't do this in legalize
-  // because the a constant vector is typically transformed to a constant pool
-  // so we have no knowledge of the shift amount.
-  if (!Subtarget->hasSSE2())
-    return SDValue();
-
-  if (VT != MVT::v2i64 && VT != MVT::v4i32 && VT != MVT::v8i16 &&
-      (!Subtarget->hasInt256() ||
-       (VT != MVT::v4i64 && VT != MVT::v8i32 && VT != MVT::v16i16)))
-    return SDValue();
-
-  SDValue ShAmtOp = N->getOperand(1);
-  EVT EltVT = VT.getVectorElementType();
-  DebugLoc DL = N->getDebugLoc();
-  SDValue BaseShAmt = SDValue();
-  if (ShAmtOp.getOpcode() == ISD::BUILD_VECTOR) {
-    unsigned NumElts = VT.getVectorNumElements();
-    unsigned i = 0;
-    for (; i != NumElts; ++i) {
-      SDValue Arg = ShAmtOp.getOperand(i);
-      if (Arg.getOpcode() == ISD::UNDEF) continue;
-      BaseShAmt = Arg;
-      break;
-    }
-    // Handle the case where the build_vector is all undef
-    // FIXME: Should DAG allow this?
-    if (i == NumElts)
-      return SDValue();
-
-    for (; i != NumElts; ++i) {
-      SDValue Arg = ShAmtOp.getOperand(i);
-      if (Arg.getOpcode() == ISD::UNDEF) continue;
-      if (Arg != BaseShAmt) {
-        return SDValue();
-      }
-    }
-  } else if (ShAmtOp.getOpcode() == ISD::VECTOR_SHUFFLE &&
-             cast<ShuffleVectorSDNode>(ShAmtOp)->isSplat()) {
-    SDValue InVec = ShAmtOp.getOperand(0);
-    if (InVec.getOpcode() == ISD::BUILD_VECTOR) {
-      unsigned NumElts = InVec.getValueType().getVectorNumElements();
-      unsigned i = 0;
-      for (; i != NumElts; ++i) {
-        SDValue Arg = InVec.getOperand(i);
-        if (Arg.getOpcode() == ISD::UNDEF) continue;
-        BaseShAmt = Arg;
-        break;
-      }
-    } else if (InVec.getOpcode() == ISD::INSERT_VECTOR_ELT) {
-       if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(InVec.getOperand(2))) {
-         unsigned SplatIdx= cast<ShuffleVectorSDNode>(ShAmtOp)->getSplatIndex();
-         if (C->getZExtValue() == SplatIdx)
-           BaseShAmt = InVec.getOperand(1);
-       }
-    }
-    if (BaseShAmt.getNode() == 0) {
-      // Don't create instructions with illegal types after legalize
-      // types has run.
-      if (!DAG.getTargetLoweringInfo().isTypeLegal(EltVT) &&
-          !DCI.isBeforeLegalize())
-        return SDValue();
-
-      BaseShAmt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, EltVT, ShAmtOp,
-                              DAG.getIntPtrConstant(0));
-    }
-  } else
-    return SDValue();
-
-  // The shift amount is an i32.
-  if (EltVT.bitsGT(MVT::i32))
-    BaseShAmt = DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, BaseShAmt);
-  else if (EltVT.bitsLT(MVT::i32))
-    BaseShAmt = DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i32, BaseShAmt);
-
-  // The shift amount is identical so we can do a vector shift.
-  SDValue  ValOp = N->getOperand(0);
-  switch (N->getOpcode()) {
-  default:
-    llvm_unreachable("Unknown shift opcode!");
-  case ISD::SHL:
-    switch (VT.getSimpleVT().SimpleTy) {
-    default: return SDValue();
-    case MVT::v2i64:
-    case MVT::v4i32:
-    case MVT::v8i16:
-    case MVT::v4i64:
-    case MVT::v8i32:
-    case MVT::v16i16:
-      return getTargetVShiftNode(X86ISD::VSHLI, DL, VT, ValOp, BaseShAmt, DAG);
-    }
-  case ISD::SRA:
-    switch (VT.getSimpleVT().SimpleTy) {
-    default: return SDValue();
-    case MVT::v4i32:
-    case MVT::v8i16:
-    case MVT::v8i32:
-    case MVT::v16i16:
-      return getTargetVShiftNode(X86ISD::VSRAI, DL, VT, ValOp, BaseShAmt, DAG);
-    }
-  case ISD::SRL:
-    switch (VT.getSimpleVT().SimpleTy) {
-    default: return SDValue();
-    case MVT::v2i64:
-    case MVT::v4i32:
-    case MVT::v8i16:
-    case MVT::v4i64:
-    case MVT::v8i32:
-    case MVT::v16i16:
-      return getTargetVShiftNode(X86ISD::VSRLI, DL, VT, ValOp, BaseShAmt, DAG);
-    }
-  }
+  return SDValue();
 }
 
 // CMPEQCombine - Recognize the distinctive  (AND (setcc ...) (setcc ..))
@@ -16379,13 +16453,19 @@ static SDValue PerformOrCombine(SDNode *N, SelectionDAG &DAG,
       // Validate that the Mask operand is a vector sra node.
       // FIXME: what to do for bytes, since there is a psignb/pblendvb, but
       // there is no psrai.b
-      if (Mask.getOpcode() != X86ISD::VSRAI)
-        return SDValue();
-
-      // Check that the SRA is all signbits.
-      SDValue SraC = Mask.getOperand(1);
-      unsigned SraAmt  = cast<ConstantSDNode>(SraC)->getZExtValue();
       unsigned EltBits = MaskVT.getVectorElementType().getSizeInBits();
+      unsigned SraAmt = ~0;
+      if (Mask.getOpcode() == ISD::SRA) {
+        SDValue Amt = Mask.getOperand(1);
+        if (isSplatVector(Amt.getNode())) {
+          SDValue SclrAmt = Amt->getOperand(0);
+          if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(SclrAmt))
+            SraAmt = C->getZExtValue();
+        }
+      } else if (Mask.getOpcode() == X86ISD::VSRAI) {
+        SDValue SraC = Mask.getOperand(1);
+        SraAmt  = cast<ConstantSDNode>(SraC)->getZExtValue();
+      }
       if ((SraAmt + 1) != EltBits)
         return SDValue();
 
diff --git a/test/CodeGen/X86/pr15296.ll b/test/CodeGen/X86/pr15296.ll
new file mode 100644
index 0000000000..1187d80cdf
--- /dev/null
+++ b/test/CodeGen/X86/pr15296.ll
@@ -0,0 +1,46 @@
+; RUN: llc < %s -mtriple=i686-pc-linux -mcpu=corei7-avx | FileCheck %s
+
+define <8 x i32> @shiftInput___vyuunu(<8 x i32> %input, i32 %shiftval, <8 x i32> %__mask) nounwind {
+allocas:
+  %smear.0 = insertelement <8 x i32> undef, i32 %shiftval, i32 0
+  %smear.1 = insertelement <8 x i32> %smear.0, i32 %shiftval, i32 1
+  %smear.2 = insertelement <8 x i32> %smear.1, i32 %shiftval, i32 2
+  %smear.3 = insertelement <8 x i32> %smear.2, i32 %shiftval, i32 3
+  %smear.4 = insertelement <8 x i32> %smear.3, i32 %shiftval, i32 4
+  %smear.5 = insertelement <8 x i32> %smear.4, i32 %shiftval, i32 5
+  %smear.6 = insertelement <8 x i32> %smear.5, i32 %shiftval, i32 6
+  %smear.7 = insertelement <8 x i32> %smear.6, i32 %shiftval, i32 7
+  %bitop = lshr <8 x i32> %input, %smear.7
+  ret <8 x i32> %bitop
+}
+
+; CHECK: shiftInput___vyuunu
+; CHECK: psrld
+; CHECK: psrld
+; CHECK: ret
+
+define <8 x i32> @shiftInput___canonical(<8 x i32> %input, i32 %shiftval, <8 x i32> %__mask) nounwind {
+allocas:
+  %smear.0 = insertelement <8 x i32> undef, i32 %shiftval, i32 0
+  %smear.7 = shufflevector <8 x i32> %smear.0, <8 x i32> undef, <8 x i32> zeroinitializer
+  %bitop = lshr <8 x i32> %input, %smear.7
+  ret <8 x i32> %bitop
+}
+
+; CHECK: shiftInput___canonical
+; CHECK: psrld
+; CHECK: psrld
+; CHECK: ret
+
+define <4 x i64> @shiftInput___64in32bitmode(<4 x i64> %input, i64 %shiftval, <4 x i64> %__mask) nounwind {
+allocas:
+  %smear.0 = insertelement <4 x i64> undef, i64 %shiftval, i32 0
+  %smear.7 = shufflevector <4 x i64> %smear.0, <4 x i64> undef, <4 x i32> zeroinitializer
+  %bitop = lshr <4 x i64> %input, %smear.7
+  ret <4 x i64> %bitop
+}
+
+; CHECK: shiftInput___64in32bitmode
+; CHECK: psrlq
+; CHECK: psrlq
+; CHECK: ret