SparcISelDAGToDAG.cpp revision 7d052f272d3f9ad0acdebf6811e29d529f70c1e1 
1//===-- SparcISelDAGToDAG.cpp - A dag to dag inst selector for Sparc ------===//
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 SPARC target.
11//
12//===----------------------------------------------------------------------===//
13
14#include "SparcTargetMachine.h"
15#include "llvm/CodeGen/SelectionDAGISel.h"
16#include "llvm/IR/Intrinsics.h"
17#include "llvm/Support/Compiler.h"
18#include "llvm/Support/Debug.h"
19#include "llvm/Support/ErrorHandling.h"
20#include "llvm/Support/raw_ostream.h"
21using namespace llvm;
22
23//===----------------------------------------------------------------------===//
24// Instruction Selector Implementation
25//===----------------------------------------------------------------------===//
26
27//===--------------------------------------------------------------------===//
28/// SparcDAGToDAGISel - SPARC specific code to select SPARC machine
29/// instructions for SelectionDAG operations.
30///
31namespace {
32class SparcDAGToDAGISel : public SelectionDAGISel {
33  /// Subtarget - Keep a pointer to the Sparc Subtarget around so that we can
34  /// make the right decision when generating code for different targets.
35  const SparcSubtarget &Subtarget;
36  SparcTargetMachine &TM;
37public:
38  explicit SparcDAGToDAGISel(SparcTargetMachine &tm)
39    : SelectionDAGISel(tm),
40      Subtarget(tm.getSubtarget<SparcSubtarget>()),
41      TM(tm) {
42  }
43
44  SDNode *Select(SDNode *N);
45
46  // Complex Pattern Selectors.
47  bool SelectADDRrr(SDValue N, SDValue &R1, SDValue &R2);
48  bool SelectADDRri(SDValue N, SDValue &Base, SDValue &Offset);
49
50  /// SelectInlineAsmMemoryOperand - Implement addressing mode selection for
51  /// inline asm expressions.
52  virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
53                                            char ConstraintCode,
54                                            std::vector<SDValue> &OutOps);
55
56  virtual const char *getPassName() const {
57    return "SPARC DAG->DAG Pattern Instruction Selection";
58  }
59
60  // Include the pieces autogenerated from the target description.
61#include "SparcGenDAGISel.inc"
62
63private:
64  SDNode* getGlobalBaseReg();
65};
66}  // end anonymous namespace
67
68SDNode* SparcDAGToDAGISel::getGlobalBaseReg() {
69  unsigned GlobalBaseReg = TM.getInstrInfo()->getGlobalBaseReg(MF);
70  return CurDAG->getRegister(GlobalBaseReg,
71                             getTargetLowering()->getPointerTy()).getNode();
72}
73
74bool SparcDAGToDAGISel::SelectADDRri(SDValue Addr,
75                                     SDValue &Base, SDValue &Offset) {
76  if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
77    Base = CurDAG->getTargetFrameIndex(FIN->getIndex(),
78                                       getTargetLowering()->getPointerTy());
79    Offset = CurDAG->getTargetConstant(0, MVT::i32);
80    return true;
81  }
82  if (Addr.getOpcode() == ISD::TargetExternalSymbol ||
83      Addr.getOpcode() == ISD::TargetGlobalAddress ||
84      Addr.getOpcode() == ISD::TargetGlobalTLSAddress)
85    return false;  // direct calls.
86
87  if (Addr.getOpcode() == ISD::ADD) {
88    if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) {
89      if (isInt<13>(CN->getSExtValue())) {
90        if (FrameIndexSDNode *FIN =
91                dyn_cast<FrameIndexSDNode>(Addr.getOperand(0))) {
92          // Constant offset from frame ref.
93          Base = CurDAG->getTargetFrameIndex(FIN->getIndex(),
94                                           getTargetLowering()->getPointerTy());
95        } else {
96          Base = Addr.getOperand(0);
97        }
98        Offset = CurDAG->getTargetConstant(CN->getZExtValue(), MVT::i32);
99        return true;
100      }
101    }
102    if (Addr.getOperand(0).getOpcode() == SPISD::Lo) {
103      Base = Addr.getOperand(1);
104      Offset = Addr.getOperand(0).getOperand(0);
105      return true;
106    }
107    if (Addr.getOperand(1).getOpcode() == SPISD::Lo) {
108      Base = Addr.getOperand(0);
109      Offset = Addr.getOperand(1).getOperand(0);
110      return true;
111    }
112  }
113  Base = Addr;
114  Offset = CurDAG->getTargetConstant(0, MVT::i32);
115  return true;
116}
117
118bool SparcDAGToDAGISel::SelectADDRrr(SDValue Addr, SDValue &R1, SDValue &R2) {
119  if (Addr.getOpcode() == ISD::FrameIndex) return false;
120  if (Addr.getOpcode() == ISD::TargetExternalSymbol ||
121      Addr.getOpcode() == ISD::TargetGlobalAddress ||
122      Addr.getOpcode() == ISD::TargetGlobalTLSAddress)
123    return false;  // direct calls.
124
125  if (Addr.getOpcode() == ISD::ADD) {
126    if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1)))
127      if (isInt<13>(CN->getSExtValue()))
128        return false;  // Let the reg+imm pattern catch this!
129    if (Addr.getOperand(0).getOpcode() == SPISD::Lo ||
130        Addr.getOperand(1).getOpcode() == SPISD::Lo)
131      return false;  // Let the reg+imm pattern catch this!
132    R1 = Addr.getOperand(0);
133    R2 = Addr.getOperand(1);
134    return true;
135  }
136
137  R1 = Addr;
138  R2 = CurDAG->getRegister(SP::G0, getTargetLowering()->getPointerTy());
139  return true;
140}
141
142SDNode *SparcDAGToDAGISel::Select(SDNode *N) {
143  SDLoc dl(N);
144  if (N->isMachineOpcode())
145    return NULL;   // Already selected.
146
147  switch (N->getOpcode()) {
148  default: break;
149  case SPISD::GLOBAL_BASE_REG:
150    return getGlobalBaseReg();
151
152  case ISD::SDIV:
153  case ISD::UDIV: {
154    // sdivx / udivx handle 64-bit divides.
155    if (N->getValueType(0) == MVT::i64)
156      break;
157    // FIXME: should use a custom expander to expose the SRA to the dag.
158    SDValue DivLHS = N->getOperand(0);
159    SDValue DivRHS = N->getOperand(1);
160
161    // Set the Y register to the high-part.
162    SDValue TopPart;
163    if (N->getOpcode() == ISD::SDIV) {
164      TopPart = SDValue(CurDAG->getMachineNode(SP::SRAri, dl, MVT::i32, DivLHS,
165                                   CurDAG->getTargetConstant(31, MVT::i32)), 0);
166    } else {
167      TopPart = CurDAG->getRegister(SP::G0, MVT::i32);
168    }
169    TopPart = SDValue(CurDAG->getMachineNode(SP::WRYrr, dl, MVT::Glue, TopPart,
170                                     CurDAG->getRegister(SP::G0, MVT::i32)), 0);
171
172    // FIXME: Handle div by immediate.
173    unsigned Opcode = N->getOpcode() == ISD::SDIV ? SP::SDIVrr : SP::UDIVrr;
174    return CurDAG->SelectNodeTo(N, Opcode, MVT::i32, DivLHS, DivRHS,
175                                TopPart);
176  }
177  case ISD::MULHU:
178  case ISD::MULHS: {
179    // FIXME: Handle mul by immediate.
180    SDValue MulLHS = N->getOperand(0);
181    SDValue MulRHS = N->getOperand(1);
182    unsigned Opcode = N->getOpcode() == ISD::MULHU ? SP::UMULrr : SP::SMULrr;
183    SDNode *Mul = CurDAG->getMachineNode(Opcode, dl, MVT::i32, MVT::Glue,
184                                         MulLHS, MulRHS);
185    // The high part is in the Y register.
186    return CurDAG->SelectNodeTo(N, SP::RDY, MVT::i32, SDValue(Mul, 1));
187  }
188  }
189
190  return SelectCode(N);
191}
192
193
194/// SelectInlineAsmMemoryOperand - Implement addressing mode selection for
195/// inline asm expressions.
196bool
197SparcDAGToDAGISel::SelectInlineAsmMemoryOperand(const SDValue &Op,
198                                                char ConstraintCode,
199                                                std::vector<SDValue> &OutOps) {
200  SDValue Op0, Op1;
201  switch (ConstraintCode) {
202  default: return true;
203  case 'm':   // memory
204   if (!SelectADDRrr(Op, Op0, Op1))
205     SelectADDRri(Op, Op0, Op1);
206   break;
207  }
208
209  OutOps.push_back(Op0);
210  OutOps.push_back(Op1);
211  return false;
212}
213
214/// createSparcISelDag - This pass converts a legalized DAG into a
215/// SPARC-specific DAG, ready for instruction scheduling.
216///
217FunctionPass *llvm::createSparcISelDag(SparcTargetMachine &TM) {
218  return new SparcDAGToDAGISel(TM);
219}
220