1 //===-- LanaiISelDAGToDAG.cpp - A dag to dag inst selector for Lanai ------===//
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 Lanai target.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "Lanai.h"
15 #include "LanaiMachineFunctionInfo.h"
16 #include "LanaiRegisterInfo.h"
17 #include "LanaiSubtarget.h"
18 #include "LanaiTargetMachine.h"
19 #include "llvm/CodeGen/MachineConstantPool.h"
20 #include "llvm/CodeGen/MachineFrameInfo.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineInstrBuilder.h"
23 #include "llvm/CodeGen/MachineRegisterInfo.h"
24 #include "llvm/CodeGen/SelectionDAGISel.h"
25 #include "llvm/IR/CFG.h"
26 #include "llvm/IR/GlobalValue.h"
27 #include "llvm/IR/Instructions.h"
28 #include "llvm/IR/Intrinsics.h"
29 #include "llvm/IR/Type.h"
30 #include "llvm/Support/Debug.h"
31 #include "llvm/Support/ErrorHandling.h"
32 #include "llvm/Support/raw_ostream.h"
33 #include "llvm/Target/TargetMachine.h"
34
35 using namespace llvm;
36
37 #define DEBUG_TYPE "lanai-isel"
38
39 //===----------------------------------------------------------------------===//
40 // Instruction Selector Implementation
41 //===----------------------------------------------------------------------===//
42
43 //===----------------------------------------------------------------------===//
44 // LanaiDAGToDAGISel - Lanai specific code to select Lanai machine
45 // instructions for SelectionDAG operations.
46 //===----------------------------------------------------------------------===//
47 namespace {
48
49 class LanaiDAGToDAGISel : public SelectionDAGISel {
50 public:
LanaiDAGToDAGISel(LanaiTargetMachine & TargetMachine)51 explicit LanaiDAGToDAGISel(LanaiTargetMachine &TargetMachine)
52 : SelectionDAGISel(TargetMachine) {}
53
runOnMachineFunction(MachineFunction & MF)54 bool runOnMachineFunction(MachineFunction &MF) override {
55 return SelectionDAGISel::runOnMachineFunction(MF);
56 }
57
58 // Pass Name
getPassName() const59 const char *getPassName() const override {
60 return "Lanai DAG->DAG Pattern Instruction Selection";
61 }
62
63 bool SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintCode,
64 std::vector<SDValue> &OutOps) override;
65
66 private:
67 // Include the pieces autogenerated from the target description.
68 #include "LanaiGenDAGISel.inc"
69
70 // Instruction Selection not handled by the auto-generated tablgen
71 void Select(SDNode *N) override;
72
73 // Support functions for the opcodes of Instruction Selection
74 // not handled by the auto-generated tablgen
75 void selectFrameIndex(SDNode *N);
76
77 // Complex Pattern for address selection.
78 bool selectAddrRi(SDValue Addr, SDValue &Base, SDValue &Offset,
79 SDValue &AluOp);
80 bool selectAddrRr(SDValue Addr, SDValue &R1, SDValue &R2, SDValue &AluOp);
81 bool selectAddrSls(SDValue Addr, SDValue &Offset);
82 bool selectAddrSpls(SDValue Addr, SDValue &Base, SDValue &Offset,
83 SDValue &AluOp);
84
85 // getI32Imm - Return a target constant with the specified value, of type i32.
getI32Imm(unsigned Imm,const SDLoc & DL)86 inline SDValue getI32Imm(unsigned Imm, const SDLoc &DL) {
87 return CurDAG->getTargetConstant(Imm, DL, MVT::i32);
88 }
89
90 private:
91 bool selectAddrRiSpls(SDValue Addr, SDValue &Base, SDValue &Offset,
92 SDValue &AluOp, bool RiMode);
93 };
94
canBeRepresentedAsSls(const ConstantSDNode & CN)95 bool canBeRepresentedAsSls(const ConstantSDNode &CN) {
96 // Fits in 21-bit signed immediate and two low-order bits are zero.
97 return isInt<21>(CN.getSExtValue()) && ((CN.getSExtValue() & 0x3) == 0);
98 }
99
100 } // namespace
101
102 // Helper functions for ComplexPattern used on LanaiInstrInfo
103 // Used on Lanai Load/Store instructions.
selectAddrSls(SDValue Addr,SDValue & Offset)104 bool LanaiDAGToDAGISel::selectAddrSls(SDValue Addr, SDValue &Offset) {
105 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr)) {
106 SDLoc DL(Addr);
107 // Loading from a constant address.
108 if (canBeRepresentedAsSls(*CN)) {
109 int32_t Imm = CN->getSExtValue();
110 Offset = CurDAG->getTargetConstant(Imm, DL, CN->getValueType(0));
111 return true;
112 }
113 }
114 if (Addr.getOpcode() == ISD::OR &&
115 Addr.getOperand(1).getOpcode() == LanaiISD::SMALL) {
116 Offset = Addr.getOperand(1).getOperand(0);
117 return true;
118 }
119 return false;
120 }
121
selectAddrRiSpls(SDValue Addr,SDValue & Base,SDValue & Offset,SDValue & AluOp,bool RiMode)122 bool LanaiDAGToDAGISel::selectAddrRiSpls(SDValue Addr, SDValue &Base,
123 SDValue &Offset, SDValue &AluOp,
124 bool RiMode) {
125 SDLoc DL(Addr);
126
127 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr)) {
128 if (RiMode) {
129 // Fits in 16-bit signed immediate.
130 if (isInt<16>(CN->getSExtValue())) {
131 int16_t Imm = CN->getSExtValue();
132 Offset = CurDAG->getTargetConstant(Imm, DL, CN->getValueType(0));
133 Base = CurDAG->getRegister(Lanai::R0, CN->getValueType(0));
134 AluOp = CurDAG->getTargetConstant(LPAC::ADD, DL, MVT::i32);
135 return true;
136 }
137 // Allow SLS to match if the constant doesn't fit in 16 bits but can be
138 // represented as an SLS.
139 if (canBeRepresentedAsSls(*CN))
140 return false;
141 } else {
142 // Fits in 10-bit signed immediate.
143 if (isInt<10>(CN->getSExtValue())) {
144 int16_t Imm = CN->getSExtValue();
145 Offset = CurDAG->getTargetConstant(Imm, DL, CN->getValueType(0));
146 Base = CurDAG->getRegister(Lanai::R0, CN->getValueType(0));
147 AluOp = CurDAG->getTargetConstant(LPAC::ADD, DL, MVT::i32);
148 return true;
149 }
150 }
151 }
152
153 // if Address is FI, get the TargetFrameIndex.
154 if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
155 Base = CurDAG->getTargetFrameIndex(
156 FIN->getIndex(),
157 getTargetLowering()->getPointerTy(CurDAG->getDataLayout()));
158 Offset = CurDAG->getTargetConstant(0, DL, MVT::i32);
159 AluOp = CurDAG->getTargetConstant(LPAC::ADD, DL, MVT::i32);
160 return true;
161 }
162
163 // Skip direct calls
164 if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
165 Addr.getOpcode() == ISD::TargetGlobalAddress))
166 return false;
167
168 // Address of the form imm + reg
169 ISD::NodeType AluOperator = static_cast<ISD::NodeType>(Addr.getOpcode());
170 if (AluOperator == ISD::ADD) {
171 AluOp = CurDAG->getTargetConstant(LPAC::ADD, DL, MVT::i32);
172 // Addresses of the form FI+const
173 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1)))
174 if ((RiMode && isInt<16>(CN->getSExtValue())) ||
175 (!RiMode && isInt<10>(CN->getSExtValue()))) {
176 // If the first operand is a FI, get the TargetFI Node
177 if (FrameIndexSDNode *FIN =
178 dyn_cast<FrameIndexSDNode>(Addr.getOperand(0))) {
179 Base = CurDAG->getTargetFrameIndex(
180 FIN->getIndex(),
181 getTargetLowering()->getPointerTy(CurDAG->getDataLayout()));
182 } else {
183 Base = Addr.getOperand(0);
184 }
185
186 Offset = CurDAG->getTargetConstant(CN->getSExtValue(), DL, MVT::i32);
187 return true;
188 }
189 }
190
191 // Let SLS match SMALL instead of RI.
192 if (AluOperator == ISD::OR && RiMode &&
193 Addr.getOperand(1).getOpcode() == LanaiISD::SMALL)
194 return false;
195
196 Base = Addr;
197 Offset = CurDAG->getTargetConstant(0, DL, MVT::i32);
198 AluOp = CurDAG->getTargetConstant(LPAC::ADD, DL, MVT::i32);
199 return true;
200 }
201
selectAddrRi(SDValue Addr,SDValue & Base,SDValue & Offset,SDValue & AluOp)202 bool LanaiDAGToDAGISel::selectAddrRi(SDValue Addr, SDValue &Base,
203 SDValue &Offset, SDValue &AluOp) {
204 return selectAddrRiSpls(Addr, Base, Offset, AluOp, /*RImode=*/true);
205 }
206
selectAddrSpls(SDValue Addr,SDValue & Base,SDValue & Offset,SDValue & AluOp)207 bool LanaiDAGToDAGISel::selectAddrSpls(SDValue Addr, SDValue &Base,
208 SDValue &Offset, SDValue &AluOp) {
209 return selectAddrRiSpls(Addr, Base, Offset, AluOp, /*RiMode=*/false);
210 }
211
selectAddrRr(SDValue Addr,SDValue & R1,SDValue & R2,SDValue & AluOp)212 bool LanaiDAGToDAGISel::selectAddrRr(SDValue Addr, SDValue &R1, SDValue &R2,
213 SDValue &AluOp) {
214 // if Address is FI, get the TargetFrameIndex.
215 if (Addr.getOpcode() == ISD::FrameIndex)
216 return false;
217
218 // Skip direct calls
219 if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
220 Addr.getOpcode() == ISD::TargetGlobalAddress))
221 return false;
222
223 // Address of the form OP + OP
224 ISD::NodeType AluOperator = static_cast<ISD::NodeType>(Addr.getOpcode());
225 LPAC::AluCode AluCode = LPAC::isdToLanaiAluCode(AluOperator);
226 if (AluCode != LPAC::UNKNOWN) {
227 // Skip addresses of the form FI OP const
228 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1)))
229 if (isInt<16>(CN->getSExtValue()))
230 return false;
231
232 // Skip addresses with hi/lo operands
233 if (Addr.getOperand(0).getOpcode() == LanaiISD::HI ||
234 Addr.getOperand(0).getOpcode() == LanaiISD::LO ||
235 Addr.getOperand(0).getOpcode() == LanaiISD::SMALL ||
236 Addr.getOperand(1).getOpcode() == LanaiISD::HI ||
237 Addr.getOperand(1).getOpcode() == LanaiISD::LO ||
238 Addr.getOperand(1).getOpcode() == LanaiISD::SMALL)
239 return false;
240
241 // Addresses of the form register OP register
242 R1 = Addr.getOperand(0);
243 R2 = Addr.getOperand(1);
244 AluOp = CurDAG->getTargetConstant(AluCode, SDLoc(Addr), MVT::i32);
245 return true;
246 }
247
248 // Skip addresses with zero offset
249 return false;
250 }
251
SelectInlineAsmMemoryOperand(const SDValue & Op,unsigned ConstraintCode,std::vector<SDValue> & OutOps)252 bool LanaiDAGToDAGISel::SelectInlineAsmMemoryOperand(
253 const SDValue &Op, unsigned ConstraintCode, std::vector<SDValue> &OutOps) {
254 SDValue Op0, Op1, AluOp;
255 switch (ConstraintCode) {
256 default:
257 return true;
258 case InlineAsm::Constraint_m: // memory
259 if (!selectAddrRr(Op, Op0, Op1, AluOp) &&
260 !selectAddrRi(Op, Op0, Op1, AluOp))
261 return true;
262 break;
263 }
264
265 OutOps.push_back(Op0);
266 OutOps.push_back(Op1);
267 OutOps.push_back(AluOp);
268 return false;
269 }
270
271 // Select instructions not customized! Used for
272 // expanded, promoted and normal instructions
Select(SDNode * Node)273 void LanaiDAGToDAGISel::Select(SDNode *Node) {
274 unsigned Opcode = Node->getOpcode();
275
276 // Dump information about the Node being selected
277 DEBUG(errs() << "Selecting: "; Node->dump(CurDAG); errs() << "\n");
278
279 // If we have a custom node, we already have selected!
280 if (Node->isMachineOpcode()) {
281 DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
282 return;
283 }
284
285 // Instruction Selection not handled by the auto-generated
286 // tablegen selection should be handled here.
287 switch (Opcode) {
288 case ISD::FrameIndex:
289 selectFrameIndex(Node);
290 return;
291 default:
292 break;
293 }
294
295 // Select the default instruction
296 SelectCode(Node);
297 }
298
selectFrameIndex(SDNode * Node)299 void LanaiDAGToDAGISel::selectFrameIndex(SDNode *Node) {
300 SDLoc DL(Node);
301 SDValue Imm = CurDAG->getTargetConstant(0, DL, MVT::i32);
302 int FI = dyn_cast<FrameIndexSDNode>(Node)->getIndex();
303 EVT VT = Node->getValueType(0);
304 SDValue TFI = CurDAG->getTargetFrameIndex(FI, VT);
305 unsigned Opc = Lanai::ADD_I_LO;
306 if (Node->hasOneUse()) {
307 CurDAG->SelectNodeTo(Node, Opc, VT, TFI, Imm);
308 return;
309 }
310 ReplaceNode(Node, CurDAG->getMachineNode(Opc, DL, VT, TFI, Imm));
311 }
312
313 // createLanaiISelDag - This pass converts a legalized DAG into a
314 // Lanai-specific DAG, ready for instruction scheduling.
createLanaiISelDag(LanaiTargetMachine & TM)315 FunctionPass *llvm::createLanaiISelDag(LanaiTargetMachine &TM) {
316 return new LanaiDAGToDAGISel(TM);
317 }
318