[AArch64] Generate vector signed/unsigned mul and mla/mls long.

Phabricator Revision: http://reviews.llvm.org/D5589
Patch by Balaram Makam <bmakam@codeaurora.org>!!

llvm-svn: 219276

3 files changed, 248 insertions, 0 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index ebb9b8e5d86..5cfd6645c65 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -531,6 +531,11 @@ AArch64TargetLowering::AArch64TargetLowering(const TargetMachine &TM)
 
     // AArch64 doesn't have MUL.2d:
     setOperationAction(ISD::MUL, MVT::v2i64, Expand);
+    // Custom handling for some quad-vector types to detect MULL.
+    setOperationAction(ISD::MUL, MVT::v8i16, Custom);
+    setOperationAction(ISD::MUL, MVT::v4i32, Custom);
+    setOperationAction(ISD::MUL, MVT::v2i64, Custom);
+
     setOperationAction(ISD::ANY_EXTEND, MVT::v4i32, Legal);
     setTruncStoreAction(MVT::v2i32, MVT::v2i16, Expand);
     // Likewise, narrowing and extending vector loads/stores aren't handled
@@ -853,6 +858,8 @@ const char *AArch64TargetLowering::getTargetNodeName(unsigned Opcode) const {
   case AArch64ISD::ST2LANEpost:       return "AArch64ISD::ST2LANEpost";
   case AArch64ISD::ST3LANEpost:       return "AArch64ISD::ST3LANEpost";
   case AArch64ISD::ST4LANEpost:       return "AArch64ISD::ST4LANEpost";
+  case AArch64ISD::SMULL:             return "AArch64ISD::SMULL";
+  case AArch64ISD::UMULL:             return "AArch64ISD::UMULL";
   }
 }
 
@@ -1668,6 +1675,197 @@ static SDValue LowerBITCAST(SDValue Op, SelectionDAG &DAG) {
       0);
 }
 
+static EVT getExtensionTo64Bits(const EVT &OrigVT) {
+  if (OrigVT.getSizeInBits() >= 64)
+    return OrigVT;
+
+  assert(OrigVT.isSimple() && "Expecting a simple value type");
+
+  MVT::SimpleValueType OrigSimpleTy = OrigVT.getSimpleVT().SimpleTy;
+  switch (OrigSimpleTy) {
+  default: llvm_unreachable("Unexpected Vector Type");
+  case MVT::v2i8:
+  case MVT::v2i16:
+     return MVT::v2i32;
+  case MVT::v4i8:
+    return  MVT::v4i16;
+  }
+}
+
+static SDValue addRequiredExtensionForVectorMULL(SDValue N, SelectionDAG &DAG,
+                                                 const EVT &OrigTy,
+                                                 const EVT &ExtTy,
+                                                 unsigned ExtOpcode) {
+  // The vector originally had a size of OrigTy. It was then extended to ExtTy.
+  // We expect the ExtTy to be 128-bits total. If the OrigTy is less than
+  // 64-bits we need to insert a new extension so that it will be 64-bits.
+  assert(ExtTy.is128BitVector() && "Unexpected extension size");
+  if (OrigTy.getSizeInBits() >= 64)
+    return N;
+
+  // Must extend size to at least 64 bits to be used as an operand for VMULL.
+  EVT NewVT = getExtensionTo64Bits(OrigTy);
+
+  return DAG.getNode(ExtOpcode, SDLoc(N), NewVT, N);
+}
+
+static bool isExtendedBUILD_VECTOR(SDNode *N, SelectionDAG &DAG,
+                                   bool isSigned) {
+  EVT VT = N->getValueType(0);
+
+  if (N->getOpcode() != ISD::BUILD_VECTOR)
+    return false;
+
+  for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
+    SDNode *Elt = N->getOperand(i).getNode();
+    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Elt)) {
+      unsigned EltSize = VT.getVectorElementType().getSizeInBits();
+      unsigned HalfSize = EltSize / 2;
+      if (isSigned) {
+        if (!isIntN(HalfSize, C->getSExtValue()))
+          return false;
+      } else {
+        if (!isUIntN(HalfSize, C->getZExtValue()))
+          return false;
+      }
+      continue;
+    }
+    return false;
+  }
+
+  return true;
+}
+
+static SDValue skipExtensionForVectorMULL(SDNode *N, SelectionDAG &DAG) {
+  if (N->getOpcode() == ISD::SIGN_EXTEND || N->getOpcode() == ISD::ZERO_EXTEND)
+    return addRequiredExtensionForVectorMULL(N->getOperand(0), DAG,
+                                             N->getOperand(0)->getValueType(0),
+                                             N->getValueType(0),
+                                             N->getOpcode());
+
+  assert(N->getOpcode() == ISD::BUILD_VECTOR && "expected BUILD_VECTOR");
+  EVT VT = N->getValueType(0);
+  unsigned EltSize = VT.getVectorElementType().getSizeInBits() / 2;
+  unsigned NumElts = VT.getVectorNumElements();
+  MVT TruncVT = MVT::getIntegerVT(EltSize);
+  SmallVector<SDValue, 8> Ops;
+  for (unsigned i = 0; i != NumElts; ++i) {
+    ConstantSDNode *C = cast<ConstantSDNode>(N->getOperand(i));
+    const APInt &CInt = C->getAPIntValue();
+    // Element types smaller than 32 bits are not legal, so use i32 elements.
+    // The values are implicitly truncated so sext vs. zext doesn't matter.
+    Ops.push_back(DAG.getConstant(CInt.zextOrTrunc(32), MVT::i32));
+  }
+  return DAG.getNode(ISD::BUILD_VECTOR, SDLoc(N),
+                     MVT::getVectorVT(TruncVT, NumElts), Ops);
+}
+
+static bool isSignExtended(SDNode *N, SelectionDAG &DAG) {
+  if (N->getOpcode() == ISD::SIGN_EXTEND)
+    return true;
+  if (isExtendedBUILD_VECTOR(N, DAG, true))
+    return true;
+  return false;
+}
+
+static bool isZeroExtended(SDNode *N, SelectionDAG &DAG) {
+  if (N->getOpcode() == ISD::ZERO_EXTEND)
+    return true;
+  if (isExtendedBUILD_VECTOR(N, DAG, false))
+    return true;
+  return false;
+}
+
+static bool isAddSubSExt(SDNode *N, SelectionDAG &DAG) {
+  unsigned Opcode = N->getOpcode();
+  if (Opcode == ISD::ADD || Opcode == ISD::SUB) {
+    SDNode *N0 = N->getOperand(0).getNode();
+    SDNode *N1 = N->getOperand(1).getNode();
+    return N0->hasOneUse() && N1->hasOneUse() &&
+      isSignExtended(N0, DAG) && isSignExtended(N1, DAG);
+  }
+  return false;
+}
+
+static bool isAddSubZExt(SDNode *N, SelectionDAG &DAG) {
+  unsigned Opcode = N->getOpcode();
+  if (Opcode == ISD::ADD || Opcode == ISD::SUB) {
+    SDNode *N0 = N->getOperand(0).getNode();
+    SDNode *N1 = N->getOperand(1).getNode();
+    return N0->hasOneUse() && N1->hasOneUse() &&
+      isZeroExtended(N0, DAG) && isZeroExtended(N1, DAG);
+  }
+  return false;
+}
+
+static SDValue LowerMUL(SDValue Op, SelectionDAG &DAG) {
+  // Multiplications are only custom-lowered for 128-bit vectors so that
+  // VMULL can be detected.  Otherwise v2i64 multiplications are not legal.
+  EVT VT = Op.getValueType();
+  assert(VT.is128BitVector() && VT.isInteger() &&
+         "unexpected type for custom-lowering ISD::MUL");
+  SDNode *N0 = Op.getOperand(0).getNode();
+  SDNode *N1 = Op.getOperand(1).getNode();
+  unsigned NewOpc = 0;
+  bool isMLA = false;
+  bool isN0SExt = isSignExtended(N0, DAG);
+  bool isN1SExt = isSignExtended(N1, DAG);
+  if (isN0SExt && isN1SExt)
+    NewOpc = AArch64ISD::SMULL;
+  else {
+    bool isN0ZExt = isZeroExtended(N0, DAG);
+    bool isN1ZExt = isZeroExtended(N1, DAG);
+    if (isN0ZExt && isN1ZExt)
+      NewOpc = AArch64ISD::UMULL;
+    else if (isN1SExt || isN1ZExt) {
+      // Look for (s/zext A + s/zext B) * (s/zext C). We want to turn these
+      // into (s/zext A * s/zext C) + (s/zext B * s/zext C)
+      if (isN1SExt && isAddSubSExt(N0, DAG)) {
+        NewOpc = AArch64ISD::SMULL;
+        isMLA = true;
+      } else if (isN1ZExt && isAddSubZExt(N0, DAG)) {
+        NewOpc =  AArch64ISD::UMULL;
+        isMLA = true;
+      } else if (isN0ZExt && isAddSubZExt(N1, DAG)) {
+        std::swap(N0, N1);
+        NewOpc =  AArch64ISD::UMULL;
+        isMLA = true;
+      }
+    }
+
+    if (!NewOpc) {
+      if (VT == MVT::v2i64)
+        // Fall through to expand this.  It is not legal.
+        return SDValue();
+      else
+        // Other vector multiplications are legal.
+        return Op;
+    }
+  }
+
+  // Legalize to a S/UMULL instruction
+  SDLoc DL(Op);
+  SDValue Op0;
+  SDValue Op1 = skipExtensionForVectorMULL(N1, DAG);
+  if (!isMLA) {
+    Op0 = skipExtensionForVectorMULL(N0, DAG);
+    assert(Op0.getValueType().is64BitVector() &&
+           Op1.getValueType().is64BitVector() &&
+           "unexpected types for extended operands to VMULL");
+    return DAG.getNode(NewOpc, DL, VT, Op0, Op1);
+  }
+  // Optimizing (zext A + zext B) * C, to (S/UMULL A, C) + (S/UMULL B, C) during
+  // isel lowering to take advantage of no-stall back to back s/umul + s/umla.
+  // This is true for CPUs with accumulate forwarding such as Cortex-A53/A57
+  SDValue N00 = skipExtensionForVectorMULL(N0->getOperand(0).getNode(), DAG);
+  SDValue N01 = skipExtensionForVectorMULL(N0->getOperand(1).getNode(), DAG);
+  EVT Op1VT = Op1.getValueType();
+  return DAG.getNode(N0->getOpcode(), DL, VT,
+                     DAG.getNode(NewOpc, DL, VT,
+                               DAG.getNode(ISD::BITCAST, DL, Op1VT, N00), Op1),
+                     DAG.getNode(NewOpc, DL, VT,
+                               DAG.getNode(ISD::BITCAST, DL, Op1VT, N01), Op1));
+}
 
 SDValue AArch64TargetLowering::LowerOperation(SDValue Op,
                                               SelectionDAG &DAG) const {
@@ -1768,6 +1966,8 @@ SDValue AArch64TargetLowering::LowerOperation(SDValue Op,
     return LowerFP_TO_INT(Op, DAG);
   case ISD::FSINCOS:
     return LowerFSINCOS(Op, DAG);
+  case ISD::MUL:
+    return LowerMUL(Op, DAG);
   }
 }
 
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.h b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
index 3e960ca75f5..2f5708dd897 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.h
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
@@ -169,6 +169,9 @@ enum {
   /// mode without emitting such REV instructions.
   NVCAST,
 
+  SMULL,
+  UMULL,
+
   // NEON Load/Store with post-increment base updates
   LD2post = ISD::FIRST_TARGET_MEMORY_OPCODE,
   LD3post,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index c2e2e8b22de..831defa3987 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -239,6 +239,11 @@ def AArch64WrapperLarge : SDNode<"AArch64ISD::WrapperLarge",
 
 def AArch64NvCast : SDNode<"AArch64ISD::NVCAST", SDTUnaryOp>;
 
+def SDT_AArch64mull : SDTypeProfile<1, 2, [SDTCisInt<0>, SDTCisInt<1>,
+                                    SDTCisSameAs<1, 2>]>;
+def AArch64smull    : SDNode<"AArch64ISD::SMULL", SDT_AArch64mull>;
+def AArch64umull    : SDNode<"AArch64ISD::UMULL", SDT_AArch64mull>;
+
 //===----------------------------------------------------------------------===//
 
 //===----------------------------------------------------------------------===//
@@ -3148,6 +3153,46 @@ defm USUBL   : SIMDLongThreeVectorBHS<1, 0b0010, "usubl",
 defm USUBW   : SIMDWideThreeVectorBHS<   1, 0b0011, "usubw",
                  BinOpFrag<(sub node:$LHS, (zext node:$RHS))>>;
 
+// Additional patterns for SMULL and UMULL
+multiclass Neon_mul_widen_patterns<SDPatternOperator opnode,
+  Instruction INST8B, Instruction INST4H, Instruction INST2S> {
+  def : Pat<(v8i16 (opnode (v8i8 V64:$Rn), (v8i8 V64:$Rm))),
+            (INST8B V64:$Rn, V64:$Rm)>;
+  def : Pat<(v4i32 (opnode (v4i16 V64:$Rn), (v4i16 V64:$Rm))),
+            (INST4H V64:$Rn, V64:$Rm)>;
+  def : Pat<(v2i64 (opnode (v2i32 V64:$Rn), (v2i32 V64:$Rm))),
+            (INST2S V64:$Rn, V64:$Rm)>;
+}
+
+defm : Neon_mul_widen_patterns<AArch64smull, SMULLv8i8_v8i16,
+  SMULLv4i16_v4i32, SMULLv2i32_v2i64>;
+defm : Neon_mul_widen_patterns<AArch64umull, UMULLv8i8_v8i16,
+  UMULLv4i16_v4i32, UMULLv2i32_v2i64>;
+
+// Additional patterns for SMLAL/SMLSL and UMLAL/UMLSL
+multiclass Neon_mulacc_widen_patterns<SDPatternOperator opnode,
+  Instruction INST8B, Instruction INST4H, Instruction INST2S> {
+  def : Pat<(v8i16 (opnode (v8i16 V128:$Rd), (v8i8 V64:$Rn), (v8i8 V64:$Rm))),
+            (INST8B V128:$Rd, V64:$Rn, V64:$Rm)>;
+  def : Pat<(v4i32 (opnode (v4i32 V128:$Rd), (v4i16 V64:$Rn), (v4i16 V64:$Rm))),
+            (INST4H V128:$Rd, V64:$Rn, V64:$Rm)>;
+  def : Pat<(v2i64 (opnode (v2i64 V128:$Rd), (v2i32 V64:$Rn), (v2i32 V64:$Rm))),
+            (INST2S  V128:$Rd, V64:$Rn, V64:$Rm)>;
+}
+
+defm : Neon_mulacc_widen_patterns<
+  TriOpFrag<(add node:$LHS, (AArch64smull node:$MHS, node:$RHS))>,
+  SMLALv8i8_v8i16, SMLALv4i16_v4i32, SMLALv2i32_v2i64>;
+defm : Neon_mulacc_widen_patterns<
+  TriOpFrag<(add node:$LHS, (AArch64umull node:$MHS, node:$RHS))>,
+  UMLALv8i8_v8i16, UMLALv4i16_v4i32, UMLALv2i32_v2i64>;
+defm : Neon_mulacc_widen_patterns<
+  TriOpFrag<(sub node:$LHS, (AArch64smull node:$MHS, node:$RHS))>,
+  SMLSLv8i8_v8i16, SMLSLv4i16_v4i32, SMLSLv2i32_v2i64>;
+defm : Neon_mulacc_widen_patterns<
+  TriOpFrag<(sub node:$LHS, (AArch64umull node:$MHS, node:$RHS))>,
+  UMLSLv8i8_v8i16, UMLSLv4i16_v4i32, UMLSLv2i32_v2i64>;
+
 // Patterns for 64-bit pmull
 def : Pat<(int_aarch64_neon_pmull64 V64:$Rn, V64:$Rm),
           (PMULLv1i64 V64:$Rn, V64:$Rm)>;