LLVM  8.0.0svn
XCoreISelDAGToDAG.cpp
Go to the documentation of this file.
1 //===-- XCoreISelDAGToDAG.cpp - A dag to dag inst selector for XCore ------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines an instruction selector for the XCore target.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "XCore.h"
15 #include "XCoreTargetMachine.h"
23 #include "llvm/IR/CallingConv.h"
24 #include "llvm/IR/Constants.h"
25 #include "llvm/IR/DerivedTypes.h"
26 #include "llvm/IR/Function.h"
27 #include "llvm/IR/Intrinsics.h"
28 #include "llvm/IR/LLVMContext.h"
29 #include "llvm/Support/Debug.h"
32 using namespace llvm;
33 
34 /// XCoreDAGToDAGISel - XCore specific code to select XCore machine
35 /// instructions for SelectionDAG operations.
36 ///
37 namespace {
38  class XCoreDAGToDAGISel : public SelectionDAGISel {
39 
40  public:
41  XCoreDAGToDAGISel(XCoreTargetMachine &TM, CodeGenOpt::Level OptLevel)
42  : SelectionDAGISel(TM, OptLevel) {}
43 
44  void Select(SDNode *N) override;
45  bool tryBRIND(SDNode *N);
46 
47  /// getI32Imm - Return a target constant with the specified value, of type
48  /// i32.
49  inline SDValue getI32Imm(unsigned Imm, const SDLoc &dl) {
50  return CurDAG->getTargetConstant(Imm, dl, MVT::i32);
51  }
52 
53  inline bool immMskBitp(SDNode *inN) const {
54  ConstantSDNode *N = cast<ConstantSDNode>(inN);
55  uint32_t value = (uint32_t)N->getZExtValue();
56  if (!isMask_32(value)) {
57  return false;
58  }
59  int msksize = 32 - countLeadingZeros(value);
60  return (msksize >= 1 && msksize <= 8) ||
61  msksize == 16 || msksize == 24 || msksize == 32;
62  }
63 
64  // Complex Pattern Selectors.
65  bool SelectADDRspii(SDValue Addr, SDValue &Base, SDValue &Offset);
66 
67  bool SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
68  std::vector<SDValue> &OutOps) override;
69 
70  StringRef getPassName() const override {
71  return "XCore DAG->DAG Pattern Instruction Selection";
72  }
73 
74  // Include the pieces autogenerated from the target description.
75  #include "XCoreGenDAGISel.inc"
76  };
77 } // end anonymous namespace
78 
79 /// createXCoreISelDag - This pass converts a legalized DAG into a
80 /// XCore-specific DAG, ready for instruction scheduling.
81 ///
83  CodeGenOpt::Level OptLevel) {
84  return new XCoreDAGToDAGISel(TM, OptLevel);
85 }
86 
87 bool XCoreDAGToDAGISel::SelectADDRspii(SDValue Addr, SDValue &Base,
88  SDValue &Offset) {
89  FrameIndexSDNode *FIN = nullptr;
90  if ((FIN = dyn_cast<FrameIndexSDNode>(Addr))) {
91  Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
92  Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), MVT::i32);
93  return true;
94  }
95  if (Addr.getOpcode() == ISD::ADD) {
96  ConstantSDNode *CN = nullptr;
97  if ((FIN = dyn_cast<FrameIndexSDNode>(Addr.getOperand(0)))
98  && (CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1)))
99  && (CN->getSExtValue() % 4 == 0 && CN->getSExtValue() >= 0)) {
100  // Constant positive word offset from frame index
101  Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
102  Offset = CurDAG->getTargetConstant(CN->getSExtValue(), SDLoc(Addr),
103  MVT::i32);
104  return true;
105  }
106  }
107  return false;
108 }
109 
110 bool XCoreDAGToDAGISel::
111 SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
112  std::vector<SDValue> &OutOps) {
113  SDValue Reg;
114  switch (ConstraintID) {
115  default: return true;
116  case InlineAsm::Constraint_m: // Memory.
117  switch (Op.getOpcode()) {
118  default: return true;
120  Reg = CurDAG->getRegister(XCore::CP, MVT::i32);
121  break;
123  Reg = CurDAG->getRegister(XCore::DP, MVT::i32);
124  break;
125  }
126  }
127  OutOps.push_back(Reg);
128  OutOps.push_back(Op.getOperand(0));
129  return false;
130 }
131 
133  SDLoc dl(N);
134  switch (N->getOpcode()) {
135  default: break;
136  case ISD::Constant: {
137  uint64_t Val = cast<ConstantSDNode>(N)->getZExtValue();
138  if (immMskBitp(N)) {
139  // Transformation function: get the size of a mask
140  // Look for the first non-zero bit
141  SDValue MskSize = getI32Imm(32 - countLeadingZeros((uint32_t)Val), dl);
142  ReplaceNode(N, CurDAG->getMachineNode(XCore::MKMSK_rus, dl,
143  MVT::i32, MskSize));
144  return;
145  }
146  else if (!isUInt<16>(Val)) {
147  SDValue CPIdx = CurDAG->getTargetConstantPool(
148  ConstantInt::get(Type::getInt32Ty(*CurDAG->getContext()), Val),
149  getTargetLowering()->getPointerTy(CurDAG->getDataLayout()));
150  SDNode *node = CurDAG->getMachineNode(XCore::LDWCP_lru6, dl, MVT::i32,
151  MVT::Other, CPIdx,
152  CurDAG->getEntryNode());
153  MachineMemOperand *MemOp =
154  MF->getMachineMemOperand(MachinePointerInfo::getConstantPool(*MF),
156  CurDAG->setNodeMemRefs(cast<MachineSDNode>(node), {MemOp});
157  ReplaceNode(N, node);
158  return;
159  }
160  break;
161  }
162  case XCoreISD::LADD: {
163  SDValue Ops[] = { N->getOperand(0), N->getOperand(1),
164  N->getOperand(2) };
165  ReplaceNode(N, CurDAG->getMachineNode(XCore::LADD_l5r, dl, MVT::i32,
166  MVT::i32, Ops));
167  return;
168  }
169  case XCoreISD::LSUB: {
170  SDValue Ops[] = { N->getOperand(0), N->getOperand(1),
171  N->getOperand(2) };
172  ReplaceNode(N, CurDAG->getMachineNode(XCore::LSUB_l5r, dl, MVT::i32,
173  MVT::i32, Ops));
174  return;
175  }
176  case XCoreISD::MACCU: {
177  SDValue Ops[] = { N->getOperand(0), N->getOperand(1),
178  N->getOperand(2), N->getOperand(3) };
179  ReplaceNode(N, CurDAG->getMachineNode(XCore::MACCU_l4r, dl, MVT::i32,
180  MVT::i32, Ops));
181  return;
182  }
183  case XCoreISD::MACCS: {
184  SDValue Ops[] = { N->getOperand(0), N->getOperand(1),
185  N->getOperand(2), N->getOperand(3) };
186  ReplaceNode(N, CurDAG->getMachineNode(XCore::MACCS_l4r, dl, MVT::i32,
187  MVT::i32, Ops));
188  return;
189  }
190  case XCoreISD::LMUL: {
191  SDValue Ops[] = { N->getOperand(0), N->getOperand(1),
192  N->getOperand(2), N->getOperand(3) };
193  ReplaceNode(N, CurDAG->getMachineNode(XCore::LMUL_l6r, dl, MVT::i32,
194  MVT::i32, Ops));
195  return;
196  }
197  case XCoreISD::CRC8: {
198  SDValue Ops[] = { N->getOperand(0), N->getOperand(1), N->getOperand(2) };
199  ReplaceNode(N, CurDAG->getMachineNode(XCore::CRC8_l4r, dl, MVT::i32,
200  MVT::i32, Ops));
201  return;
202  }
203  case ISD::BRIND:
204  if (tryBRIND(N))
205  return;
206  break;
207  // Other cases are autogenerated.
208  }
209  SelectCode(N);
210 }
211 
212 /// Given a chain return a new chain where any appearance of Old is replaced
213 /// by New. There must be at most one instruction between Old and Chain and
214 /// this instruction must be a TokenFactor. Returns an empty SDValue if
215 /// these conditions don't hold.
216 static SDValue
218 {
219  if (Chain == Old)
220  return New;
221  if (Chain->getOpcode() != ISD::TokenFactor)
222  return SDValue();
224  bool found = false;
225  for (unsigned i = 0, e = Chain->getNumOperands(); i != e; ++i) {
226  if (Chain->getOperand(i) == Old) {
227  Ops.push_back(New);
228  found = true;
229  } else {
230  Ops.push_back(Chain->getOperand(i));
231  }
232  }
233  if (!found)
234  return SDValue();
235  return CurDAG->getNode(ISD::TokenFactor, SDLoc(Chain), MVT::Other, Ops);
236 }
237 
238 bool XCoreDAGToDAGISel::tryBRIND(SDNode *N) {
239  SDLoc dl(N);
240  // (brind (int_xcore_checkevent (addr)))
241  SDValue Chain = N->getOperand(0);
242  SDValue Addr = N->getOperand(1);
243  if (Addr->getOpcode() != ISD::INTRINSIC_W_CHAIN)
244  return false;
245  unsigned IntNo = cast<ConstantSDNode>(Addr->getOperand(1))->getZExtValue();
246  if (IntNo != Intrinsic::xcore_checkevent)
247  return false;
248  SDValue nextAddr = Addr->getOperand(2);
249  SDValue CheckEventChainOut(Addr.getNode(), 1);
250  if (!CheckEventChainOut.use_empty()) {
251  // If the chain out of the checkevent intrinsic is an operand of the
252  // indirect branch or used in a TokenFactor which is the operand of the
253  // indirect branch then build a new chain which uses the chain coming into
254  // the checkevent intrinsic instead.
255  SDValue CheckEventChainIn = Addr->getOperand(0);
256  SDValue NewChain = replaceInChain(CurDAG, Chain, CheckEventChainOut,
257  CheckEventChainIn);
258  if (!NewChain.getNode())
259  return false;
260  Chain = NewChain;
261  }
262  // Enable events on the thread using setsr 1 and then disable them immediately
263  // after with clrsr 1. If any resources owned by the thread are ready an event
264  // will be taken. If no resource is ready we branch to the address which was
265  // the operand to the checkevent intrinsic.
266  SDValue constOne = getI32Imm(1, dl);
267  SDValue Glue =
268  SDValue(CurDAG->getMachineNode(XCore::SETSR_branch_u6, dl, MVT::Glue,
269  constOne, Chain), 0);
270  Glue =
271  SDValue(CurDAG->getMachineNode(XCore::CLRSR_branch_u6, dl, MVT::Glue,
272  constOne, Glue), 0);
273  if (nextAddr->getOpcode() == XCoreISD::PCRelativeWrapper &&
274  nextAddr->getOperand(0)->getOpcode() == ISD::TargetBlockAddress) {
275  CurDAG->SelectNodeTo(N, XCore::BRFU_lu6, MVT::Other,
276  nextAddr->getOperand(0), Glue);
277  return true;
278  }
279  CurDAG->SelectNodeTo(N, XCore::BAU_1r, MVT::Other, nextAddr, Glue);
280  return true;
281 }
static SDValue replaceInChain(SelectionDAG *CurDAG, SDValue Chain, SDValue Old, SDValue New)
Given a chain return a new chain where any appearance of Old is replaced by New.
unsigned getOpcode() const
Return the SelectionDAG opcode value for this node.
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
unsigned Reg
SDNode * getNode() const
get the SDNode which holds the desired result
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, ArrayRef< SDUse > Ops)
Gets or creates the specified node.
std::size_t countLeadingZeros(T Val, ZeroBehavior ZB=ZB_Width)
Count number of 0&#39;s from the most significant bit to the least stopping at the first 1...
Definition: MathExtras.h:189
constexpr bool isMask_32(uint32_t Value)
Return true if the argument is a non-empty sequence of ones starting at the least significant bit wit...
Definition: MathExtras.h:405
RESULT,OUTCHAIN = INTRINSIC_W_CHAIN(INCHAIN, INTRINSICID, arg1, ...) This node represents a target in...
Definition: ISDOpcodes.h:159
A description of a memory reference used in the backend.
int64_t getSExtValue() const
Simple integer binary arithmetic operators.
Definition: ISDOpcodes.h:201
FunctionPass * createXCoreISelDag(XCoreTargetMachine &TM, CodeGenOpt::Level OptLevel)
createXCoreISelDag - This pass converts a legalized DAG into a XCore-specific DAG, ready for instruction scheduling.
const SDValue & getOperand(unsigned Num) const
This file contains the declarations for the subclasses of Constant, which represent the different fla...
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:285
unsigned getNumOperands() const
Return the number of values used by this operation.
TokenFactor - This node takes multiple tokens as input and produces a single token result...
Definition: ISDOpcodes.h:50
This is used to represent a portion of an LLVM function in a low-level Data Dependence DAG representa...
Definition: SelectionDAG.h:222
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:847
Wrapper class for IR location info (IR ordering and DebugLoc) to be passed into SDNode creation funct...
static Constant * get(Type *Ty, uint64_t V, bool isSigned=false)
If Ty is a vector type, return a Constant with a splat of the given value.
Definition: Constants.cpp:621
Represents one node in the SelectionDAG.
SelectionDAGISel - This is the common base class used for SelectionDAG-based pattern-matching instruc...
The memory access reads data.
static IntegerType * getInt32Ty(LLVMContext &C)
Definition: Type.cpp:176
#define N
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:323
unsigned getOpcode() const
constexpr bool isUInt< 16 >(uint64_t x)
Definition: MathExtras.h:346
static MachinePointerInfo getConstantPool(MachineFunction &MF)
Return a MachinePointerInfo record that refers to the constant pool.
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
const SDValue & getOperand(unsigned i) const
uint64_t getZExtValue() const
Unlike LLVM values, Selection DAG nodes may return multiple values as the result of a computation...
This file describes how to lower LLVM code to machine code.
BRIND - Indirect branch.
Definition: ISDOpcodes.h:594