1 //===-- SparcISelDAGToDAG.cpp - A dag to dag inst selector for Sparc ------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines an instruction selector for the SPARC target.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "SparcTargetMachine.h"
14 #include "llvm/CodeGen/MachineRegisterInfo.h"
15 #include "llvm/CodeGen/SelectionDAGISel.h"
16 #include "llvm/IR/Intrinsics.h"
17 #include "llvm/Support/Debug.h"
18 #include "llvm/Support/ErrorHandling.h"
19 #include "llvm/Support/raw_ostream.h"
20 using namespace llvm;
21
22 #define DEBUG_TYPE "sparc-isel"
23 #define PASS_NAME "SPARC DAG->DAG Pattern Instruction Selection"
24
25 //===----------------------------------------------------------------------===//
26 // Instruction Selector Implementation
27 //===----------------------------------------------------------------------===//
28
29 //===--------------------------------------------------------------------===//
30 /// SparcDAGToDAGISel - SPARC specific code to select SPARC machine
31 /// instructions for SelectionDAG operations.
32 ///
33 namespace {
34 class SparcDAGToDAGISel : public SelectionDAGISel {
35 /// Subtarget - Keep a pointer to the Sparc Subtarget around so that we can
36 /// make the right decision when generating code for different targets.
37 const SparcSubtarget *Subtarget = nullptr;
38 public:
39 static char ID;
40
41 SparcDAGToDAGISel() = delete;
42
SparcDAGToDAGISel(SparcTargetMachine & tm)43 explicit SparcDAGToDAGISel(SparcTargetMachine &tm) : SelectionDAGISel(ID, tm) {}
44
runOnMachineFunction(MachineFunction & MF)45 bool runOnMachineFunction(MachineFunction &MF) override {
46 Subtarget = &MF.getSubtarget<SparcSubtarget>();
47 return SelectionDAGISel::runOnMachineFunction(MF);
48 }
49
50 void Select(SDNode *N) override;
51
52 // Complex Pattern Selectors.
53 bool SelectADDRrr(SDValue N, SDValue &R1, SDValue &R2);
54 bool SelectADDRri(SDValue N, SDValue &Base, SDValue &Offset);
55
56 /// SelectInlineAsmMemoryOperand - Implement addressing mode selection for
57 /// inline asm expressions.
58 bool SelectInlineAsmMemoryOperand(const SDValue &Op,
59 InlineAsm::ConstraintCode ConstraintID,
60 std::vector<SDValue> &OutOps) override;
61
62 // Include the pieces autogenerated from the target description.
63 #include "SparcGenDAGISel.inc"
64
65 private:
66 SDNode* getGlobalBaseReg();
67 bool tryInlineAsm(SDNode *N);
68 };
69 } // end anonymous namespace
70
71 char SparcDAGToDAGISel::ID = 0;
72
INITIALIZE_PASS(SparcDAGToDAGISel,DEBUG_TYPE,PASS_NAME,false,false)73 INITIALIZE_PASS(SparcDAGToDAGISel, DEBUG_TYPE, PASS_NAME, false, false)
74
75 SDNode* SparcDAGToDAGISel::getGlobalBaseReg() {
76 Register GlobalBaseReg = Subtarget->getInstrInfo()->getGlobalBaseReg(MF);
77 return CurDAG->getRegister(GlobalBaseReg,
78 TLI->getPointerTy(CurDAG->getDataLayout()))
79 .getNode();
80 }
81
SelectADDRri(SDValue Addr,SDValue & Base,SDValue & Offset)82 bool SparcDAGToDAGISel::SelectADDRri(SDValue Addr,
83 SDValue &Base, SDValue &Offset) {
84 if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
85 Base = CurDAG->getTargetFrameIndex(
86 FIN->getIndex(), TLI->getPointerTy(CurDAG->getDataLayout()));
87 Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), MVT::i32);
88 return true;
89 }
90 if (Addr.getOpcode() == ISD::TargetExternalSymbol ||
91 Addr.getOpcode() == ISD::TargetGlobalAddress ||
92 Addr.getOpcode() == ISD::TargetGlobalTLSAddress)
93 return false; // direct calls.
94
95 if (Addr.getOpcode() == ISD::ADD) {
96 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) {
97 if (isInt<13>(CN->getSExtValue())) {
98 if (FrameIndexSDNode *FIN =
99 dyn_cast<FrameIndexSDNode>(Addr.getOperand(0))) {
100 // Constant offset from frame ref.
101 Base = CurDAG->getTargetFrameIndex(
102 FIN->getIndex(), TLI->getPointerTy(CurDAG->getDataLayout()));
103 } else {
104 Base = Addr.getOperand(0);
105 }
106 Offset = CurDAG->getTargetConstant(CN->getZExtValue(), SDLoc(Addr),
107 MVT::i32);
108 return true;
109 }
110 }
111 if (Addr.getOperand(0).getOpcode() == SPISD::Lo) {
112 Base = Addr.getOperand(1);
113 Offset = Addr.getOperand(0).getOperand(0);
114 return true;
115 }
116 if (Addr.getOperand(1).getOpcode() == SPISD::Lo) {
117 Base = Addr.getOperand(0);
118 Offset = Addr.getOperand(1).getOperand(0);
119 return true;
120 }
121 }
122 Base = Addr;
123 Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), MVT::i32);
124 return true;
125 }
126
SelectADDRrr(SDValue Addr,SDValue & R1,SDValue & R2)127 bool SparcDAGToDAGISel::SelectADDRrr(SDValue Addr, SDValue &R1, SDValue &R2) {
128 if (Addr.getOpcode() == ISD::FrameIndex) return false;
129 if (Addr.getOpcode() == ISD::TargetExternalSymbol ||
130 Addr.getOpcode() == ISD::TargetGlobalAddress ||
131 Addr.getOpcode() == ISD::TargetGlobalTLSAddress)
132 return false; // direct calls.
133
134 if (Addr.getOpcode() == ISD::ADD) {
135 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1)))
136 if (isInt<13>(CN->getSExtValue()))
137 return false; // Let the reg+imm pattern catch this!
138 if (Addr.getOperand(0).getOpcode() == SPISD::Lo ||
139 Addr.getOperand(1).getOpcode() == SPISD::Lo)
140 return false; // Let the reg+imm pattern catch this!
141 R1 = Addr.getOperand(0);
142 R2 = Addr.getOperand(1);
143 return true;
144 }
145
146 R1 = Addr;
147 R2 = CurDAG->getRegister(SP::G0, TLI->getPointerTy(CurDAG->getDataLayout()));
148 return true;
149 }
150
151
152 // Re-assemble i64 arguments split up in SelectionDAGBuilder's
153 // visitInlineAsm / GetRegistersForValue functions.
154 //
155 // Note: This function was copied from, and is essentially identical
156 // to ARMISelDAGToDAG::SelectInlineAsm. It is very unfortunate that
157 // such hacking-up is necessary; a rethink of how inline asm operands
158 // are handled may be in order to make doing this more sane.
159 //
160 // TODO: fix inline asm support so I can simply tell it that 'i64'
161 // inputs to asm need to be allocated to the IntPair register type,
162 // and have that work. Then, delete this function.
tryInlineAsm(SDNode * N)163 bool SparcDAGToDAGISel::tryInlineAsm(SDNode *N){
164 std::vector<SDValue> AsmNodeOperands;
165 InlineAsm::Flag Flag;
166 bool Changed = false;
167 unsigned NumOps = N->getNumOperands();
168
169 // Normally, i64 data is bounded to two arbitrary GPRs for "%r"
170 // constraint. However, some instructions (e.g. ldd/std) require
171 // (even/even+1) GPRs.
172
173 // So, here, we check for this case, and mutate the inlineasm to use
174 // a single IntPair register instead, which guarantees such even/odd
175 // placement.
176
177 SDLoc dl(N);
178 SDValue Glue = N->getGluedNode() ? N->getOperand(NumOps - 1) : SDValue();
179
180 SmallVector<bool, 8> OpChanged;
181 // Glue node will be appended late.
182 for(unsigned i = 0, e = N->getGluedNode() ? NumOps - 1 : NumOps; i < e; ++i) {
183 SDValue op = N->getOperand(i);
184 AsmNodeOperands.push_back(op);
185
186 if (i < InlineAsm::Op_FirstOperand)
187 continue;
188
189 if (const auto *C = dyn_cast<ConstantSDNode>(N->getOperand(i)))
190 Flag = InlineAsm::Flag(C->getZExtValue());
191 else
192 continue;
193
194 // Immediate operands to inline asm in the SelectionDAG are modeled with
195 // two operands. The first is a constant of value InlineAsm::Kind::Imm, and
196 // the second is a constant with the value of the immediate. If we get here
197 // and we have a Kind::Imm, skip the next operand, and continue.
198 if (Flag.isImmKind()) {
199 SDValue op = N->getOperand(++i);
200 AsmNodeOperands.push_back(op);
201 continue;
202 }
203
204 const unsigned NumRegs = Flag.getNumOperandRegisters();
205 if (NumRegs)
206 OpChanged.push_back(false);
207
208 unsigned DefIdx = 0;
209 bool IsTiedToChangedOp = false;
210 // If it's a use that is tied with a previous def, it has no
211 // reg class constraint.
212 if (Changed && Flag.isUseOperandTiedToDef(DefIdx))
213 IsTiedToChangedOp = OpChanged[DefIdx];
214
215 if (!Flag.isRegUseKind() && !Flag.isRegDefKind() &&
216 !Flag.isRegDefEarlyClobberKind())
217 continue;
218
219 unsigned RC;
220 const bool HasRC = Flag.hasRegClassConstraint(RC);
221 if ((!IsTiedToChangedOp && (!HasRC || RC != SP::IntRegsRegClassID))
222 || NumRegs != 2)
223 continue;
224
225 assert((i+2 < NumOps) && "Invalid number of operands in inline asm");
226 SDValue V0 = N->getOperand(i+1);
227 SDValue V1 = N->getOperand(i+2);
228 Register Reg0 = cast<RegisterSDNode>(V0)->getReg();
229 Register Reg1 = cast<RegisterSDNode>(V1)->getReg();
230 SDValue PairedReg;
231 MachineRegisterInfo &MRI = MF->getRegInfo();
232
233 if (Flag.isRegDefKind() || Flag.isRegDefEarlyClobberKind()) {
234 // Replace the two GPRs with 1 GPRPair and copy values from GPRPair to
235 // the original GPRs.
236
237 Register GPVR = MRI.createVirtualRegister(&SP::IntPairRegClass);
238 PairedReg = CurDAG->getRegister(GPVR, MVT::v2i32);
239 SDValue Chain = SDValue(N,0);
240
241 SDNode *GU = N->getGluedUser();
242 SDValue RegCopy = CurDAG->getCopyFromReg(Chain, dl, GPVR, MVT::v2i32,
243 Chain.getValue(1));
244
245 // Extract values from a GPRPair reg and copy to the original GPR reg.
246 SDValue Sub0 = CurDAG->getTargetExtractSubreg(SP::sub_even, dl, MVT::i32,
247 RegCopy);
248 SDValue Sub1 = CurDAG->getTargetExtractSubreg(SP::sub_odd, dl, MVT::i32,
249 RegCopy);
250 SDValue T0 = CurDAG->getCopyToReg(Sub0, dl, Reg0, Sub0,
251 RegCopy.getValue(1));
252 SDValue T1 = CurDAG->getCopyToReg(Sub1, dl, Reg1, Sub1, T0.getValue(1));
253
254 // Update the original glue user.
255 std::vector<SDValue> Ops(GU->op_begin(), GU->op_end()-1);
256 Ops.push_back(T1.getValue(1));
257 CurDAG->UpdateNodeOperands(GU, Ops);
258 } else {
259 // For Kind == InlineAsm::Kind::RegUse, we first copy two GPRs into a
260 // GPRPair and then pass the GPRPair to the inline asm.
261 SDValue Chain = AsmNodeOperands[InlineAsm::Op_InputChain];
262
263 // As REG_SEQ doesn't take RegisterSDNode, we copy them first.
264 SDValue T0 = CurDAG->getCopyFromReg(Chain, dl, Reg0, MVT::i32,
265 Chain.getValue(1));
266 SDValue T1 = CurDAG->getCopyFromReg(Chain, dl, Reg1, MVT::i32,
267 T0.getValue(1));
268 SDValue Pair = SDValue(
269 CurDAG->getMachineNode(
270 TargetOpcode::REG_SEQUENCE, dl, MVT::v2i32,
271 {
272 CurDAG->getTargetConstant(SP::IntPairRegClassID, dl,
273 MVT::i32),
274 T0,
275 CurDAG->getTargetConstant(SP::sub_even, dl, MVT::i32),
276 T1,
277 CurDAG->getTargetConstant(SP::sub_odd, dl, MVT::i32),
278 }),
279 0);
280
281 // Copy REG_SEQ into a GPRPair-typed VR and replace the original two
282 // i32 VRs of inline asm with it.
283 Register GPVR = MRI.createVirtualRegister(&SP::IntPairRegClass);
284 PairedReg = CurDAG->getRegister(GPVR, MVT::v2i32);
285 Chain = CurDAG->getCopyToReg(T1, dl, GPVR, Pair, T1.getValue(1));
286
287 AsmNodeOperands[InlineAsm::Op_InputChain] = Chain;
288 Glue = Chain.getValue(1);
289 }
290
291 Changed = true;
292
293 if(PairedReg.getNode()) {
294 OpChanged[OpChanged.size() -1 ] = true;
295 Flag = InlineAsm::Flag(Flag.getKind(), 1 /* RegNum*/);
296 if (IsTiedToChangedOp)
297 Flag.setMatchingOp(DefIdx);
298 else
299 Flag.setRegClass(SP::IntPairRegClassID);
300 // Replace the current flag.
301 AsmNodeOperands[AsmNodeOperands.size() -1] = CurDAG->getTargetConstant(
302 Flag, dl, MVT::i32);
303 // Add the new register node and skip the original two GPRs.
304 AsmNodeOperands.push_back(PairedReg);
305 // Skip the next two GPRs.
306 i += 2;
307 }
308 }
309
310 if (Glue.getNode())
311 AsmNodeOperands.push_back(Glue);
312 if (!Changed)
313 return false;
314
315 SelectInlineAsmMemoryOperands(AsmNodeOperands, SDLoc(N));
316
317 SDValue New = CurDAG->getNode(N->getOpcode(), SDLoc(N),
318 CurDAG->getVTList(MVT::Other, MVT::Glue), AsmNodeOperands);
319 New->setNodeId(-1);
320 ReplaceNode(N, New.getNode());
321 return true;
322 }
323
Select(SDNode * N)324 void SparcDAGToDAGISel::Select(SDNode *N) {
325 SDLoc dl(N);
326 if (N->isMachineOpcode()) {
327 N->setNodeId(-1);
328 return; // Already selected.
329 }
330
331 switch (N->getOpcode()) {
332 default: break;
333 case ISD::INLINEASM:
334 case ISD::INLINEASM_BR: {
335 if (tryInlineAsm(N))
336 return;
337 break;
338 }
339 case SPISD::GLOBAL_BASE_REG:
340 ReplaceNode(N, getGlobalBaseReg());
341 return;
342
343 case ISD::SDIV:
344 case ISD::UDIV: {
345 // sdivx / udivx handle 64-bit divides.
346 if (N->getValueType(0) == MVT::i64)
347 break;
348 // FIXME: should use a custom expander to expose the SRA to the dag.
349 SDValue DivLHS = N->getOperand(0);
350 SDValue DivRHS = N->getOperand(1);
351
352 // Set the Y register to the high-part.
353 SDValue TopPart;
354 if (N->getOpcode() == ISD::SDIV) {
355 TopPart = SDValue(CurDAG->getMachineNode(SP::SRAri, dl, MVT::i32, DivLHS,
356 CurDAG->getTargetConstant(31, dl, MVT::i32)),
357 0);
358 } else {
359 TopPart = CurDAG->getRegister(SP::G0, MVT::i32);
360 }
361 TopPart = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, SP::Y, TopPart,
362 SDValue())
363 .getValue(1);
364
365 // FIXME: Handle div by immediate.
366 unsigned Opcode = N->getOpcode() == ISD::SDIV ? SP::SDIVrr : SP::UDIVrr;
367 CurDAG->SelectNodeTo(N, Opcode, MVT::i32, DivLHS, DivRHS, TopPart);
368 return;
369 }
370 }
371
372 SelectCode(N);
373 }
374
375
376 /// SelectInlineAsmMemoryOperand - Implement addressing mode selection for
377 /// inline asm expressions.
SelectInlineAsmMemoryOperand(const SDValue & Op,InlineAsm::ConstraintCode ConstraintID,std::vector<SDValue> & OutOps)378 bool SparcDAGToDAGISel::SelectInlineAsmMemoryOperand(
379 const SDValue &Op, InlineAsm::ConstraintCode ConstraintID,
380 std::vector<SDValue> &OutOps) {
381 SDValue Op0, Op1;
382 switch (ConstraintID) {
383 default: return true;
384 case InlineAsm::ConstraintCode::o:
385 case InlineAsm::ConstraintCode::m: // memory
386 if (!SelectADDRrr(Op, Op0, Op1))
387 SelectADDRri(Op, Op0, Op1);
388 break;
389 }
390
391 OutOps.push_back(Op0);
392 OutOps.push_back(Op1);
393 return false;
394 }
395
396 /// createSparcISelDag - This pass converts a legalized DAG into a
397 /// SPARC-specific DAG, ready for instruction scheduling.
398 ///
createSparcISelDag(SparcTargetMachine & TM)399 FunctionPass *llvm::createSparcISelDag(SparcTargetMachine &TM) {
400 return new SparcDAGToDAGISel(TM);
401 }
402