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Tom Stellard75aadc22012-12-11 21:25:42 +00001//===-- SIISelLowering.cpp - SI DAG Lowering Implementation ---------------===//
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/// \file
11/// \brief Custom DAG lowering for SI
12//
13//===----------------------------------------------------------------------===//
14
15#include "SIISelLowering.h"
16#include "AMDIL.h"
Christian Konig99ee0f42013-03-07 09:04:14 +000017#include "AMDGPU.h"
Tom Stellard75aadc22012-12-11 21:25:42 +000018#include "AMDILIntrinsicInfo.h"
19#include "SIInstrInfo.h"
20#include "SIMachineFunctionInfo.h"
21#include "SIRegisterInfo.h"
Christian Konig2c8f6d52013-03-07 09:03:52 +000022#include "llvm/IR/Function.h"
23#include "llvm/CodeGen/CallingConvLower.h"
Tom Stellard75aadc22012-12-11 21:25:42 +000024#include "llvm/CodeGen/MachineInstrBuilder.h"
25#include "llvm/CodeGen/MachineRegisterInfo.h"
26#include "llvm/CodeGen/SelectionDAG.h"
27
28using namespace llvm;
29
30SITargetLowering::SITargetLowering(TargetMachine &TM) :
31 AMDGPUTargetLowering(TM),
Christian Konigf82901a2013-02-26 17:52:23 +000032 TII(static_cast<const SIInstrInfo*>(TM.getInstrInfo())),
33 TRI(TM.getRegisterInfo()) {
Christian Konig2214f142013-03-07 09:03:38 +000034
Christian Koniga8811792013-02-16 11:28:30 +000035 addRegisterClass(MVT::i1, &AMDGPU::SReg_64RegClass);
Christian Konig2214f142013-03-07 09:03:38 +000036 addRegisterClass(MVT::i64, &AMDGPU::SReg_64RegClass);
37
38 addRegisterClass(MVT::v16i8, &AMDGPU::SReg_128RegClass);
39 addRegisterClass(MVT::v32i8, &AMDGPU::SReg_256RegClass);
40 addRegisterClass(MVT::v64i8, &AMDGPU::SReg_512RegClass);
41
42 addRegisterClass(MVT::i32, &AMDGPU::VReg_32RegClass);
43 addRegisterClass(MVT::f32, &AMDGPU::VReg_32RegClass);
Tom Stellard75aadc22012-12-11 21:25:42 +000044
Tom Stellard538ceeb2013-02-07 17:02:09 +000045 addRegisterClass(MVT::v1i32, &AMDGPU::VReg_32RegClass);
Christian Konig2214f142013-03-07 09:03:38 +000046
Tom Stellard538ceeb2013-02-07 17:02:09 +000047 addRegisterClass(MVT::v2i32, &AMDGPU::VReg_64RegClass);
Christian Konig2214f142013-03-07 09:03:38 +000048 addRegisterClass(MVT::v2f32, &AMDGPU::VReg_64RegClass);
49
Tom Stellard538ceeb2013-02-07 17:02:09 +000050 addRegisterClass(MVT::v4i32, &AMDGPU::VReg_128RegClass);
Christian Konig2214f142013-03-07 09:03:38 +000051 addRegisterClass(MVT::v4f32, &AMDGPU::VReg_128RegClass);
52
Tom Stellard538ceeb2013-02-07 17:02:09 +000053 addRegisterClass(MVT::v8i32, &AMDGPU::VReg_256RegClass);
Christian Konig2214f142013-03-07 09:03:38 +000054 addRegisterClass(MVT::v8f32, &AMDGPU::VReg_256RegClass);
55
Tom Stellard538ceeb2013-02-07 17:02:09 +000056 addRegisterClass(MVT::v16i32, &AMDGPU::VReg_512RegClass);
Christian Konig2214f142013-03-07 09:03:38 +000057 addRegisterClass(MVT::v16f32, &AMDGPU::VReg_512RegClass);
Tom Stellard75aadc22012-12-11 21:25:42 +000058
59 computeRegisterProperties();
60
Tom Stellard75aadc22012-12-11 21:25:42 +000061 setOperationAction(ISD::ADD, MVT::i64, Legal);
62 setOperationAction(ISD::ADD, MVT::i32, Legal);
63
Tom Stellard75aadc22012-12-11 21:25:42 +000064 setOperationAction(ISD::SELECT_CC, MVT::f32, Custom);
65 setOperationAction(ISD::SELECT_CC, MVT::i32, Custom);
66
67 setOperationAction(ISD::SELECT_CC, MVT::Other, Expand);
68 setTargetDAGCombine(ISD::SELECT_CC);
69
70 setTargetDAGCombine(ISD::SETCC);
Michel Danzerf52a6722013-03-08 10:58:01 +000071
72 setSchedulingPreference(Sched::Source);
Tom Stellard75aadc22012-12-11 21:25:42 +000073}
74
Christian Konig2c8f6d52013-03-07 09:03:52 +000075SDValue SITargetLowering::LowerFormalArguments(
76 SDValue Chain,
77 CallingConv::ID CallConv,
78 bool isVarArg,
79 const SmallVectorImpl<ISD::InputArg> &Ins,
80 DebugLoc DL, SelectionDAG &DAG,
81 SmallVectorImpl<SDValue> &InVals) const {
82
83 const TargetRegisterInfo *TRI = getTargetMachine().getRegisterInfo();
84
85 MachineFunction &MF = DAG.getMachineFunction();
86 FunctionType *FType = MF.getFunction()->getFunctionType();
Christian Konig99ee0f42013-03-07 09:04:14 +000087 SIMachineFunctionInfo *Info = MF.getInfo<SIMachineFunctionInfo>();
Christian Konig2c8f6d52013-03-07 09:03:52 +000088
89 assert(CallConv == CallingConv::C);
90
91 SmallVector<ISD::InputArg, 16> Splits;
Christian Konig99ee0f42013-03-07 09:04:14 +000092 uint32_t Skipped = 0;
93
94 for (unsigned i = 0, e = Ins.size(), PSInputNum = 0; i != e; ++i) {
Christian Konig2c8f6d52013-03-07 09:03:52 +000095 const ISD::InputArg &Arg = Ins[i];
96
Christian Konig99ee0f42013-03-07 09:04:14 +000097 // First check if it's a PS input addr
98 if (Info->ShaderType == ShaderType::PIXEL && !Arg.Flags.isInReg()) {
99
100 assert((PSInputNum <= 15) && "Too many PS inputs!");
101
102 if (!Arg.Used) {
103 // We can savely skip PS inputs
104 Skipped |= 1 << i;
105 ++PSInputNum;
106 continue;
107 }
108
109 Info->PSInputAddr |= 1 << PSInputNum++;
110 }
111
112 // Second split vertices into their elements
Christian Konig2c8f6d52013-03-07 09:03:52 +0000113 if (Arg.VT.isVector()) {
114 ISD::InputArg NewArg = Arg;
115 NewArg.Flags.setSplit();
116 NewArg.VT = Arg.VT.getVectorElementType();
117
118 // We REALLY want the ORIGINAL number of vertex elements here, e.g. a
119 // three or five element vertex only needs three or five registers,
120 // NOT four or eigth.
121 Type *ParamType = FType->getParamType(Arg.OrigArgIndex);
122 unsigned NumElements = ParamType->getVectorNumElements();
123
124 for (unsigned j = 0; j != NumElements; ++j) {
125 Splits.push_back(NewArg);
126 NewArg.PartOffset += NewArg.VT.getStoreSize();
127 }
128
129 } else {
130 Splits.push_back(Arg);
131 }
132 }
133
134 SmallVector<CCValAssign, 16> ArgLocs;
135 CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
136 getTargetMachine(), ArgLocs, *DAG.getContext());
137
Christian Konig99ee0f42013-03-07 09:04:14 +0000138 // At least one interpolation mode must be enabled or else the GPU will hang.
139 if (Info->ShaderType == ShaderType::PIXEL && (Info->PSInputAddr & 0x7F) == 0) {
140 Info->PSInputAddr |= 1;
141 CCInfo.AllocateReg(AMDGPU::VGPR0);
142 CCInfo.AllocateReg(AMDGPU::VGPR1);
143 }
144
Christian Konig2c8f6d52013-03-07 09:03:52 +0000145 AnalyzeFormalArguments(CCInfo, Splits);
146
147 for (unsigned i = 0, e = Ins.size(), ArgIdx = 0; i != e; ++i) {
148
Christian Konig99ee0f42013-03-07 09:04:14 +0000149 if (Skipped & (1 << i)) {
150 InVals.push_back(SDValue());
151 continue;
152 }
153
Christian Konig2c8f6d52013-03-07 09:03:52 +0000154 CCValAssign &VA = ArgLocs[ArgIdx++];
155 assert(VA.isRegLoc() && "Parameter must be in a register!");
156
157 unsigned Reg = VA.getLocReg();
158 MVT VT = VA.getLocVT();
159
160 if (VT == MVT::i64) {
161 // For now assume it is a pointer
162 Reg = TRI->getMatchingSuperReg(Reg, AMDGPU::sub0,
163 &AMDGPU::SReg_64RegClass);
164 Reg = MF.addLiveIn(Reg, &AMDGPU::SReg_64RegClass);
165 InVals.push_back(DAG.getCopyFromReg(Chain, DL, Reg, VT));
166 continue;
167 }
168
169 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg, VT);
170
171 Reg = MF.addLiveIn(Reg, RC);
172 SDValue Val = DAG.getCopyFromReg(Chain, DL, Reg, VT);
173
174 const ISD::InputArg &Arg = Ins[i];
175 if (Arg.VT.isVector()) {
176
177 // Build a vector from the registers
178 Type *ParamType = FType->getParamType(Arg.OrigArgIndex);
179 unsigned NumElements = ParamType->getVectorNumElements();
180
181 SmallVector<SDValue, 4> Regs;
182 Regs.push_back(Val);
183 for (unsigned j = 1; j != NumElements; ++j) {
184 Reg = ArgLocs[ArgIdx++].getLocReg();
185 Reg = MF.addLiveIn(Reg, RC);
186 Regs.push_back(DAG.getCopyFromReg(Chain, DL, Reg, VT));
187 }
188
189 // Fill up the missing vector elements
190 NumElements = Arg.VT.getVectorNumElements() - NumElements;
191 for (unsigned j = 0; j != NumElements; ++j)
192 Regs.push_back(DAG.getUNDEF(VT));
193
194 InVals.push_back(DAG.getNode(ISD::BUILD_VECTOR, DL, Arg.VT,
195 Regs.data(), Regs.size()));
196 continue;
197 }
198
199 InVals.push_back(Val);
200 }
201 return Chain;
202}
203
Tom Stellard75aadc22012-12-11 21:25:42 +0000204MachineBasicBlock * SITargetLowering::EmitInstrWithCustomInserter(
205 MachineInstr * MI, MachineBasicBlock * BB) const {
Tom Stellard75aadc22012-12-11 21:25:42 +0000206 MachineRegisterInfo & MRI = BB->getParent()->getRegInfo();
207 MachineBasicBlock::iterator I = MI;
208
Tom Stellard75aadc22012-12-11 21:25:42 +0000209 switch (MI->getOpcode()) {
210 default:
211 return AMDGPUTargetLowering::EmitInstrWithCustomInserter(MI, BB);
212 case AMDGPU::BRANCH: return BB;
Tom Stellard75aadc22012-12-11 21:25:42 +0000213 case AMDGPU::SI_WQM:
214 LowerSI_WQM(MI, *BB, I, MRI);
215 break;
Tom Stellard75aadc22012-12-11 21:25:42 +0000216 }
217 return BB;
218}
219
Tom Stellard75aadc22012-12-11 21:25:42 +0000220void SITargetLowering::LowerSI_WQM(MachineInstr *MI, MachineBasicBlock &BB,
221 MachineBasicBlock::iterator I, MachineRegisterInfo & MRI) const {
222 BuildMI(BB, I, BB.findDebugLoc(I), TII->get(AMDGPU::S_WQM_B64), AMDGPU::EXEC)
223 .addReg(AMDGPU::EXEC);
224
225 MI->eraseFromParent();
226}
227
Tom Stellard75aadc22012-12-11 21:25:42 +0000228EVT SITargetLowering::getSetCCResultType(EVT VT) const {
229 return MVT::i1;
230}
231
232//===----------------------------------------------------------------------===//
233// Custom DAG Lowering Operations
234//===----------------------------------------------------------------------===//
235
236SDValue SITargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
237 switch (Op.getOpcode()) {
238 default: return AMDGPUTargetLowering::LowerOperation(Op, DAG);
Tom Stellardf8794352012-12-19 22:10:31 +0000239 case ISD::BRCOND: return LowerBRCOND(Op, DAG);
Tom Stellard75aadc22012-12-11 21:25:42 +0000240 case ISD::SELECT_CC: return LowerSELECT_CC(Op, DAG);
Tom Stellard75aadc22012-12-11 21:25:42 +0000241 }
242 return SDValue();
243}
244
Tom Stellardf8794352012-12-19 22:10:31 +0000245/// \brief Helper function for LowerBRCOND
246static SDNode *findUser(SDValue Value, unsigned Opcode) {
Tom Stellard75aadc22012-12-11 21:25:42 +0000247
Tom Stellardf8794352012-12-19 22:10:31 +0000248 SDNode *Parent = Value.getNode();
249 for (SDNode::use_iterator I = Parent->use_begin(), E = Parent->use_end();
250 I != E; ++I) {
251
252 if (I.getUse().get() != Value)
253 continue;
254
255 if (I->getOpcode() == Opcode)
256 return *I;
257 }
258 return 0;
259}
260
261/// This transforms the control flow intrinsics to get the branch destination as
262/// last parameter, also switches branch target with BR if the need arise
263SDValue SITargetLowering::LowerBRCOND(SDValue BRCOND,
264 SelectionDAG &DAG) const {
265
266 DebugLoc DL = BRCOND.getDebugLoc();
267
268 SDNode *Intr = BRCOND.getOperand(1).getNode();
269 SDValue Target = BRCOND.getOperand(2);
270 SDNode *BR = 0;
271
272 if (Intr->getOpcode() == ISD::SETCC) {
273 // As long as we negate the condition everything is fine
274 SDNode *SetCC = Intr;
275 assert(SetCC->getConstantOperandVal(1) == 1);
NAKAMURA Takumi458a8272013-01-07 11:14:44 +0000276 assert(cast<CondCodeSDNode>(SetCC->getOperand(2).getNode())->get() ==
277 ISD::SETNE);
Tom Stellardf8794352012-12-19 22:10:31 +0000278 Intr = SetCC->getOperand(0).getNode();
279
280 } else {
281 // Get the target from BR if we don't negate the condition
282 BR = findUser(BRCOND, ISD::BR);
283 Target = BR->getOperand(1);
284 }
285
286 assert(Intr->getOpcode() == ISD::INTRINSIC_W_CHAIN);
287
288 // Build the result and
289 SmallVector<EVT, 4> Res;
290 for (unsigned i = 1, e = Intr->getNumValues(); i != e; ++i)
291 Res.push_back(Intr->getValueType(i));
292
293 // operands of the new intrinsic call
294 SmallVector<SDValue, 4> Ops;
295 Ops.push_back(BRCOND.getOperand(0));
296 for (unsigned i = 1, e = Intr->getNumOperands(); i != e; ++i)
297 Ops.push_back(Intr->getOperand(i));
298 Ops.push_back(Target);
299
300 // build the new intrinsic call
301 SDNode *Result = DAG.getNode(
302 Res.size() > 1 ? ISD::INTRINSIC_W_CHAIN : ISD::INTRINSIC_VOID, DL,
303 DAG.getVTList(Res.data(), Res.size()), Ops.data(), Ops.size()).getNode();
304
305 if (BR) {
306 // Give the branch instruction our target
307 SDValue Ops[] = {
308 BR->getOperand(0),
309 BRCOND.getOperand(2)
310 };
311 DAG.MorphNodeTo(BR, ISD::BR, BR->getVTList(), Ops, 2);
312 }
313
314 SDValue Chain = SDValue(Result, Result->getNumValues() - 1);
315
316 // Copy the intrinsic results to registers
317 for (unsigned i = 1, e = Intr->getNumValues() - 1; i != e; ++i) {
318 SDNode *CopyToReg = findUser(SDValue(Intr, i), ISD::CopyToReg);
319 if (!CopyToReg)
320 continue;
321
322 Chain = DAG.getCopyToReg(
323 Chain, DL,
324 CopyToReg->getOperand(1),
325 SDValue(Result, i - 1),
326 SDValue());
327
328 DAG.ReplaceAllUsesWith(SDValue(CopyToReg, 0), CopyToReg->getOperand(0));
329 }
330
331 // Remove the old intrinsic from the chain
332 DAG.ReplaceAllUsesOfValueWith(
333 SDValue(Intr, Intr->getNumValues() - 1),
334 Intr->getOperand(0));
335
336 return Chain;
Tom Stellard75aadc22012-12-11 21:25:42 +0000337}
338
Tom Stellard75aadc22012-12-11 21:25:42 +0000339SDValue SITargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const {
340 SDValue LHS = Op.getOperand(0);
341 SDValue RHS = Op.getOperand(1);
342 SDValue True = Op.getOperand(2);
343 SDValue False = Op.getOperand(3);
344 SDValue CC = Op.getOperand(4);
345 EVT VT = Op.getValueType();
346 DebugLoc DL = Op.getDebugLoc();
347
348 // Possible Min/Max pattern
349 SDValue MinMax = LowerMinMax(Op, DAG);
350 if (MinMax.getNode()) {
351 return MinMax;
352 }
353
354 SDValue Cond = DAG.getNode(ISD::SETCC, DL, MVT::i1, LHS, RHS, CC);
355 return DAG.getNode(ISD::SELECT, DL, VT, Cond, True, False);
356}
357
358//===----------------------------------------------------------------------===//
359// Custom DAG optimizations
360//===----------------------------------------------------------------------===//
361
362SDValue SITargetLowering::PerformDAGCombine(SDNode *N,
363 DAGCombinerInfo &DCI) const {
364 SelectionDAG &DAG = DCI.DAG;
365 DebugLoc DL = N->getDebugLoc();
366 EVT VT = N->getValueType(0);
367
368 switch (N->getOpcode()) {
369 default: break;
370 case ISD::SELECT_CC: {
371 N->dump();
372 ConstantSDNode *True, *False;
373 // i1 selectcc(l, r, -1, 0, cc) -> i1 setcc(l, r, cc)
374 if ((True = dyn_cast<ConstantSDNode>(N->getOperand(2)))
375 && (False = dyn_cast<ConstantSDNode>(N->getOperand(3)))
376 && True->isAllOnesValue()
377 && False->isNullValue()
378 && VT == MVT::i1) {
379 return DAG.getNode(ISD::SETCC, DL, VT, N->getOperand(0),
380 N->getOperand(1), N->getOperand(4));
381
382 }
383 break;
384 }
385 case ISD::SETCC: {
386 SDValue Arg0 = N->getOperand(0);
387 SDValue Arg1 = N->getOperand(1);
388 SDValue CC = N->getOperand(2);
389 ConstantSDNode * C = NULL;
390 ISD::CondCode CCOp = dyn_cast<CondCodeSDNode>(CC)->get();
391
392 // i1 setcc (sext(i1), 0, setne) -> i1 setcc(i1, 0, setne)
393 if (VT == MVT::i1
394 && Arg0.getOpcode() == ISD::SIGN_EXTEND
395 && Arg0.getOperand(0).getValueType() == MVT::i1
396 && (C = dyn_cast<ConstantSDNode>(Arg1))
397 && C->isNullValue()
398 && CCOp == ISD::SETNE) {
399 return SimplifySetCC(VT, Arg0.getOperand(0),
400 DAG.getConstant(0, MVT::i1), CCOp, true, DCI, DL);
401 }
402 break;
403 }
404 }
405 return SDValue();
406}
Christian Konigd910b7d2013-02-26 17:52:16 +0000407
Christian Konigf82901a2013-02-26 17:52:23 +0000408/// \brief Test if RegClass is one of the VSrc classes
409static bool isVSrc(unsigned RegClass) {
410 return AMDGPU::VSrc_32RegClassID == RegClass ||
411 AMDGPU::VSrc_64RegClassID == RegClass;
412}
413
414/// \brief Test if RegClass is one of the SSrc classes
415static bool isSSrc(unsigned RegClass) {
416 return AMDGPU::SSrc_32RegClassID == RegClass ||
417 AMDGPU::SSrc_64RegClassID == RegClass;
418}
419
420/// \brief Analyze the possible immediate value Op
421///
422/// Returns -1 if it isn't an immediate, 0 if it's and inline immediate
423/// and the immediate value if it's a literal immediate
424int32_t SITargetLowering::analyzeImmediate(const SDNode *N) const {
425
426 union {
427 int32_t I;
428 float F;
429 } Imm;
430
431 if (const ConstantSDNode *Node = dyn_cast<ConstantSDNode>(N))
432 Imm.I = Node->getSExtValue();
433 else if (const ConstantFPSDNode *Node = dyn_cast<ConstantFPSDNode>(N))
434 Imm.F = Node->getValueAPF().convertToFloat();
435 else
436 return -1; // It isn't an immediate
437
438 if ((Imm.I >= -16 && Imm.I <= 64) ||
439 Imm.F == 0.5f || Imm.F == -0.5f ||
440 Imm.F == 1.0f || Imm.F == -1.0f ||
441 Imm.F == 2.0f || Imm.F == -2.0f ||
442 Imm.F == 4.0f || Imm.F == -4.0f)
443 return 0; // It's an inline immediate
444
445 return Imm.I; // It's a literal immediate
446}
447
448/// \brief Try to fold an immediate directly into an instruction
449bool SITargetLowering::foldImm(SDValue &Operand, int32_t &Immediate,
450 bool &ScalarSlotUsed) const {
451
452 MachineSDNode *Mov = dyn_cast<MachineSDNode>(Operand);
453 if (Mov == 0 || !TII->isMov(Mov->getMachineOpcode()))
454 return false;
455
456 const SDValue &Op = Mov->getOperand(0);
457 int32_t Value = analyzeImmediate(Op.getNode());
458 if (Value == -1) {
459 // Not an immediate at all
460 return false;
461
462 } else if (Value == 0) {
463 // Inline immediates can always be fold
464 Operand = Op;
465 return true;
466
467 } else if (Value == Immediate) {
468 // Already fold literal immediate
469 Operand = Op;
470 return true;
471
472 } else if (!ScalarSlotUsed && !Immediate) {
473 // Fold this literal immediate
474 ScalarSlotUsed = true;
475 Immediate = Value;
476 Operand = Op;
477 return true;
478
479 }
480
481 return false;
482}
483
484/// \brief Does "Op" fit into register class "RegClass" ?
485bool SITargetLowering::fitsRegClass(SelectionDAG &DAG, SDValue &Op,
486 unsigned RegClass) const {
487
488 MachineRegisterInfo &MRI = DAG.getMachineFunction().getRegInfo();
489 SDNode *Node = Op.getNode();
490
491 int OpClass;
492 if (MachineSDNode *MN = dyn_cast<MachineSDNode>(Node)) {
493 const MCInstrDesc &Desc = TII->get(MN->getMachineOpcode());
494 OpClass = Desc.OpInfo[Op.getResNo()].RegClass;
495
496 } else if (Node->getOpcode() == ISD::CopyFromReg) {
497 RegisterSDNode *Reg = cast<RegisterSDNode>(Node->getOperand(1).getNode());
498 OpClass = MRI.getRegClass(Reg->getReg())->getID();
499
500 } else
501 return false;
502
503 if (OpClass == -1)
504 return false;
505
506 return TRI->getRegClass(RegClass)->hasSubClassEq(TRI->getRegClass(OpClass));
507}
508
509/// \brief Make sure that we don't exeed the number of allowed scalars
510void SITargetLowering::ensureSRegLimit(SelectionDAG &DAG, SDValue &Operand,
511 unsigned RegClass,
512 bool &ScalarSlotUsed) const {
513
514 // First map the operands register class to a destination class
515 if (RegClass == AMDGPU::VSrc_32RegClassID)
516 RegClass = AMDGPU::VReg_32RegClassID;
517 else if (RegClass == AMDGPU::VSrc_64RegClassID)
518 RegClass = AMDGPU::VReg_64RegClassID;
519 else
520 return;
521
522 // Nothing todo if they fit naturaly
523 if (fitsRegClass(DAG, Operand, RegClass))
524 return;
525
526 // If the scalar slot isn't used yet use it now
527 if (!ScalarSlotUsed) {
528 ScalarSlotUsed = true;
529 return;
530 }
531
532 // This is a conservative aproach, it is possible that we can't determine
533 // the correct register class and copy too often, but better save than sorry.
534 SDValue RC = DAG.getTargetConstant(RegClass, MVT::i32);
535 SDNode *Node = DAG.getMachineNode(TargetOpcode::COPY_TO_REGCLASS, DebugLoc(),
536 Operand.getValueType(), Operand, RC);
537 Operand = SDValue(Node, 0);
538}
539
Christian Konigd910b7d2013-02-26 17:52:16 +0000540SDNode *SITargetLowering::PostISelFolding(MachineSDNode *Node,
541 SelectionDAG &DAG) const {
Christian Konigf82901a2013-02-26 17:52:23 +0000542
543 // Original encoding (either e32 or e64)
544 int Opcode = Node->getMachineOpcode();
545 const MCInstrDesc *Desc = &TII->get(Opcode);
546
547 unsigned NumDefs = Desc->getNumDefs();
548 unsigned NumOps = Desc->getNumOperands();
549
Christian Konige500e442013-02-26 17:52:47 +0000550 // e64 version if available, -1 otherwise
551 int OpcodeE64 = AMDGPU::getVOPe64(Opcode);
552 const MCInstrDesc *DescE64 = OpcodeE64 == -1 ? 0 : &TII->get(OpcodeE64);
553
554 assert(!DescE64 || DescE64->getNumDefs() == NumDefs);
555 assert(!DescE64 || DescE64->getNumOperands() == (NumOps + 4));
556
Christian Konigf82901a2013-02-26 17:52:23 +0000557 int32_t Immediate = Desc->getSize() == 4 ? 0 : -1;
558 bool HaveVSrc = false, HaveSSrc = false;
559
560 // First figure out what we alread have in this instruction
561 for (unsigned i = 0, e = Node->getNumOperands(), Op = NumDefs;
562 i != e && Op < NumOps; ++i, ++Op) {
563
564 unsigned RegClass = Desc->OpInfo[Op].RegClass;
565 if (isVSrc(RegClass))
566 HaveVSrc = true;
567 else if (isSSrc(RegClass))
568 HaveSSrc = true;
569 else
570 continue;
571
572 int32_t Imm = analyzeImmediate(Node->getOperand(i).getNode());
573 if (Imm != -1 && Imm != 0) {
574 // Literal immediate
575 Immediate = Imm;
576 }
577 }
578
579 // If we neither have VSrc nor SSrc it makes no sense to continue
580 if (!HaveVSrc && !HaveSSrc)
581 return Node;
582
583 // No scalar allowed when we have both VSrc and SSrc
584 bool ScalarSlotUsed = HaveVSrc && HaveSSrc;
585
586 // Second go over the operands and try to fold them
587 std::vector<SDValue> Ops;
Christian Konige500e442013-02-26 17:52:47 +0000588 bool Promote2e64 = false;
Christian Konigf82901a2013-02-26 17:52:23 +0000589 for (unsigned i = 0, e = Node->getNumOperands(), Op = NumDefs;
590 i != e && Op < NumOps; ++i, ++Op) {
591
592 const SDValue &Operand = Node->getOperand(i);
593 Ops.push_back(Operand);
594
595 // Already folded immediate ?
596 if (isa<ConstantSDNode>(Operand.getNode()) ||
597 isa<ConstantFPSDNode>(Operand.getNode()))
598 continue;
599
600 // Is this a VSrc or SSrc operand ?
601 unsigned RegClass = Desc->OpInfo[Op].RegClass;
Christian Konig6612ac32013-02-26 17:52:36 +0000602 if (!isVSrc(RegClass) && !isSSrc(RegClass)) {
603
604 if (i == 1 && Desc->isCommutable() &&
605 fitsRegClass(DAG, Ops[0], RegClass) &&
606 foldImm(Ops[1], Immediate, ScalarSlotUsed)) {
607
608 assert(isVSrc(Desc->OpInfo[NumDefs].RegClass) ||
609 isSSrc(Desc->OpInfo[NumDefs].RegClass));
610
611 // Swap commutable operands
612 SDValue Tmp = Ops[1];
613 Ops[1] = Ops[0];
614 Ops[0] = Tmp;
Christian Konige500e442013-02-26 17:52:47 +0000615
616 } else if (DescE64 && !Immediate) {
617 // Test if it makes sense to switch to e64 encoding
618
619 RegClass = DescE64->OpInfo[Op].RegClass;
620 int32_t TmpImm = -1;
621 if ((isVSrc(RegClass) || isSSrc(RegClass)) &&
622 foldImm(Ops[i], TmpImm, ScalarSlotUsed)) {
623
624 Immediate = -1;
625 Promote2e64 = true;
626 Desc = DescE64;
627 DescE64 = 0;
628 }
Christian Konig6612ac32013-02-26 17:52:36 +0000629 }
Christian Konigf82901a2013-02-26 17:52:23 +0000630 continue;
Christian Konig6612ac32013-02-26 17:52:36 +0000631 }
Christian Konigf82901a2013-02-26 17:52:23 +0000632
633 // Try to fold the immediates
634 if (!foldImm(Ops[i], Immediate, ScalarSlotUsed)) {
635 // Folding didn't worked, make sure we don't hit the SReg limit
636 ensureSRegLimit(DAG, Ops[i], RegClass, ScalarSlotUsed);
637 }
638 }
639
Christian Konige500e442013-02-26 17:52:47 +0000640 if (Promote2e64) {
641 // Add the modifier flags while promoting
642 for (unsigned i = 0; i < 4; ++i)
643 Ops.push_back(DAG.getTargetConstant(0, MVT::i32));
644 }
645
Christian Konigf82901a2013-02-26 17:52:23 +0000646 // Add optional chain and glue
647 for (unsigned i = NumOps - NumDefs, e = Node->getNumOperands(); i < e; ++i)
648 Ops.push_back(Node->getOperand(i));
649
Christian Konige500e442013-02-26 17:52:47 +0000650 // Either create a complete new or update the current instruction
651 if (Promote2e64)
652 return DAG.getMachineNode(OpcodeE64, Node->getDebugLoc(),
653 Node->getVTList(), Ops.data(), Ops.size());
654 else
655 return DAG.UpdateNodeOperands(Node, Ops.data(), Ops.size());
Christian Konigd910b7d2013-02-26 17:52:16 +0000656}