xref: /NextBSD/contrib/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp (revision 4557fabb34e865d7f40be64b39c9e34fa41dbb60)
1 //===-- SIRegisterInfo.cpp - SI Register Information ---------------------===//
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 SI implementation of the TargetRegisterInfo class.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 
16 #include "SIRegisterInfo.h"
17 #include "SIInstrInfo.h"
18 #include "SIMachineFunctionInfo.h"
19 #include "llvm/CodeGen/MachineFrameInfo.h"
20 #include "llvm/CodeGen/MachineInstrBuilder.h"
21 #include "llvm/CodeGen/RegisterScavenging.h"
22 #include "llvm/IR/Function.h"
23 #include "llvm/IR/LLVMContext.h"
24 
25 using namespace llvm;
26 
SIRegisterInfo()27 SIRegisterInfo::SIRegisterInfo() : AMDGPURegisterInfo() {}
28 
reserveRegisterTuples(BitVector & Reserved,unsigned Reg) const29 void SIRegisterInfo::reserveRegisterTuples(BitVector &Reserved, unsigned Reg) const {
30   MCRegAliasIterator R(Reg, this, true);
31 
32   for (; R.isValid(); ++R)
33     Reserved.set(*R);
34 }
35 
getReservedRegs(const MachineFunction & MF) const36 BitVector SIRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
37   BitVector Reserved(getNumRegs());
38   Reserved.set(AMDGPU::INDIRECT_BASE_ADDR);
39 
40   // EXEC_LO and EXEC_HI could be allocated and used as regular register, but
41   // this seems likely to result in bugs, so I'm marking them as reserved.
42   reserveRegisterTuples(Reserved, AMDGPU::EXEC);
43   reserveRegisterTuples(Reserved, AMDGPU::FLAT_SCR);
44 
45   // Reserve some VGPRs to use as temp registers in case we have to spill VGPRs
46   reserveRegisterTuples(Reserved, AMDGPU::VGPR254);
47   reserveRegisterTuples(Reserved, AMDGPU::VGPR255);
48 
49   // Tonga and Iceland can only allocate a fixed number of SGPRs due
50   // to a hw bug.
51   if (MF.getSubtarget<AMDGPUSubtarget>().hasSGPRInitBug()) {
52     unsigned NumSGPRs = AMDGPU::SGPR_32RegClass.getNumRegs();
53     // Reserve some SGPRs for FLAT_SCRATCH and VCC (4 SGPRs).
54     // Assume XNACK_MASK is unused.
55     unsigned Limit = AMDGPUSubtarget::FIXED_SGPR_COUNT_FOR_INIT_BUG - 4;
56 
57     for (unsigned i = Limit; i < NumSGPRs; ++i) {
58       unsigned Reg = AMDGPU::SGPR_32RegClass.getRegister(i);
59       reserveRegisterTuples(Reserved, Reg);
60     }
61   }
62 
63   return Reserved;
64 }
65 
getRegPressureSetLimit(const MachineFunction & MF,unsigned Idx) const66 unsigned SIRegisterInfo::getRegPressureSetLimit(const MachineFunction &MF,
67                                                 unsigned Idx) const {
68 
69   const AMDGPUSubtarget &STI = MF.getSubtarget<AMDGPUSubtarget>();
70   // FIXME: We should adjust the max number of waves based on LDS size.
71   unsigned SGPRLimit = getNumSGPRsAllowed(STI.getGeneration(),
72                                           STI.getMaxWavesPerCU());
73   unsigned VGPRLimit = getNumVGPRsAllowed(STI.getMaxWavesPerCU());
74 
75   for (regclass_iterator I = regclass_begin(), E = regclass_end();
76        I != E; ++I) {
77 
78     unsigned NumSubRegs = std::max((int)(*I)->getSize() / 4, 1);
79     unsigned Limit;
80 
81     if (isSGPRClass(*I)) {
82       Limit = SGPRLimit / NumSubRegs;
83     } else {
84       Limit = VGPRLimit / NumSubRegs;
85     }
86 
87     const int *Sets = getRegClassPressureSets(*I);
88     assert(Sets);
89     for (unsigned i = 0; Sets[i] != -1; ++i) {
90 	    if (Sets[i] == (int)Idx)
91         return Limit;
92     }
93   }
94   return 256;
95 }
96 
requiresRegisterScavenging(const MachineFunction & Fn) const97 bool SIRegisterInfo::requiresRegisterScavenging(const MachineFunction &Fn) const {
98   return Fn.getFrameInfo()->hasStackObjects();
99 }
100 
getNumSubRegsForSpillOp(unsigned Op)101 static unsigned getNumSubRegsForSpillOp(unsigned Op) {
102 
103   switch (Op) {
104   case AMDGPU::SI_SPILL_S512_SAVE:
105   case AMDGPU::SI_SPILL_S512_RESTORE:
106   case AMDGPU::SI_SPILL_V512_SAVE:
107   case AMDGPU::SI_SPILL_V512_RESTORE:
108     return 16;
109   case AMDGPU::SI_SPILL_S256_SAVE:
110   case AMDGPU::SI_SPILL_S256_RESTORE:
111   case AMDGPU::SI_SPILL_V256_SAVE:
112   case AMDGPU::SI_SPILL_V256_RESTORE:
113     return 8;
114   case AMDGPU::SI_SPILL_S128_SAVE:
115   case AMDGPU::SI_SPILL_S128_RESTORE:
116   case AMDGPU::SI_SPILL_V128_SAVE:
117   case AMDGPU::SI_SPILL_V128_RESTORE:
118     return 4;
119   case AMDGPU::SI_SPILL_V96_SAVE:
120   case AMDGPU::SI_SPILL_V96_RESTORE:
121     return 3;
122   case AMDGPU::SI_SPILL_S64_SAVE:
123   case AMDGPU::SI_SPILL_S64_RESTORE:
124   case AMDGPU::SI_SPILL_V64_SAVE:
125   case AMDGPU::SI_SPILL_V64_RESTORE:
126     return 2;
127   case AMDGPU::SI_SPILL_S32_SAVE:
128   case AMDGPU::SI_SPILL_S32_RESTORE:
129   case AMDGPU::SI_SPILL_V32_SAVE:
130   case AMDGPU::SI_SPILL_V32_RESTORE:
131     return 1;
132   default: llvm_unreachable("Invalid spill opcode");
133   }
134 }
135 
buildScratchLoadStore(MachineBasicBlock::iterator MI,unsigned LoadStoreOp,unsigned Value,unsigned ScratchRsrcReg,unsigned ScratchOffset,int64_t Offset,RegScavenger * RS) const136 void SIRegisterInfo::buildScratchLoadStore(MachineBasicBlock::iterator MI,
137                                            unsigned LoadStoreOp,
138                                            unsigned Value,
139                                            unsigned ScratchRsrcReg,
140                                            unsigned ScratchOffset,
141                                            int64_t Offset,
142                                            RegScavenger *RS) const {
143 
144   MachineBasicBlock *MBB = MI->getParent();
145   const MachineFunction *MF = MI->getParent()->getParent();
146   const SIInstrInfo *TII =
147       static_cast<const SIInstrInfo *>(MF->getSubtarget().getInstrInfo());
148   LLVMContext &Ctx = MF->getFunction()->getContext();
149   DebugLoc DL = MI->getDebugLoc();
150   bool IsLoad = TII->get(LoadStoreOp).mayLoad();
151 
152   bool RanOutOfSGPRs = false;
153   unsigned SOffset = ScratchOffset;
154 
155   unsigned NumSubRegs = getNumSubRegsForSpillOp(MI->getOpcode());
156   unsigned Size = NumSubRegs * 4;
157 
158   if (!isUInt<12>(Offset + Size)) {
159     SOffset = RS->scavengeRegister(&AMDGPU::SGPR_32RegClass, MI, 0);
160     if (SOffset == AMDGPU::NoRegister) {
161       RanOutOfSGPRs = true;
162       SOffset = AMDGPU::SGPR0;
163     }
164     BuildMI(*MBB, MI, DL, TII->get(AMDGPU::S_ADD_U32), SOffset)
165             .addReg(ScratchOffset)
166             .addImm(Offset);
167     Offset = 0;
168   }
169 
170   if (RanOutOfSGPRs)
171     Ctx.emitError("Ran out of SGPRs for spilling VGPRS");
172 
173   for (unsigned i = 0, e = NumSubRegs; i != e; ++i, Offset += 4) {
174     unsigned SubReg = NumSubRegs > 1 ?
175         getPhysRegSubReg(Value, &AMDGPU::VGPR_32RegClass, i) :
176         Value;
177     bool IsKill = (i == e - 1);
178 
179     BuildMI(*MBB, MI, DL, TII->get(LoadStoreOp))
180             .addReg(SubReg, getDefRegState(IsLoad))
181             .addReg(ScratchRsrcReg, getKillRegState(IsKill))
182             .addReg(SOffset)
183             .addImm(Offset)
184             .addImm(0) // glc
185             .addImm(0) // slc
186             .addImm(0) // tfe
187             .addReg(Value, RegState::Implicit | getDefRegState(IsLoad));
188   }
189 }
190 
eliminateFrameIndex(MachineBasicBlock::iterator MI,int SPAdj,unsigned FIOperandNum,RegScavenger * RS) const191 void SIRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI,
192                                         int SPAdj, unsigned FIOperandNum,
193                                         RegScavenger *RS) const {
194   MachineFunction *MF = MI->getParent()->getParent();
195   MachineBasicBlock *MBB = MI->getParent();
196   SIMachineFunctionInfo *MFI = MF->getInfo<SIMachineFunctionInfo>();
197   MachineFrameInfo *FrameInfo = MF->getFrameInfo();
198   const SIInstrInfo *TII =
199       static_cast<const SIInstrInfo *>(MF->getSubtarget().getInstrInfo());
200   DebugLoc DL = MI->getDebugLoc();
201 
202   MachineOperand &FIOp = MI->getOperand(FIOperandNum);
203   int Index = MI->getOperand(FIOperandNum).getIndex();
204 
205   switch (MI->getOpcode()) {
206     // SGPR register spill
207     case AMDGPU::SI_SPILL_S512_SAVE:
208     case AMDGPU::SI_SPILL_S256_SAVE:
209     case AMDGPU::SI_SPILL_S128_SAVE:
210     case AMDGPU::SI_SPILL_S64_SAVE:
211     case AMDGPU::SI_SPILL_S32_SAVE: {
212       unsigned NumSubRegs = getNumSubRegsForSpillOp(MI->getOpcode());
213 
214       for (unsigned i = 0, e = NumSubRegs; i < e; ++i) {
215         unsigned SubReg = getPhysRegSubReg(MI->getOperand(0).getReg(),
216                                            &AMDGPU::SGPR_32RegClass, i);
217         struct SIMachineFunctionInfo::SpilledReg Spill =
218             MFI->getSpilledReg(MF, Index, i);
219 
220         if (Spill.VGPR == AMDGPU::NoRegister) {
221            LLVMContext &Ctx = MF->getFunction()->getContext();
222            Ctx.emitError("Ran out of VGPRs for spilling SGPR");
223         }
224 
225         BuildMI(*MBB, MI, DL,
226                 TII->getMCOpcodeFromPseudo(AMDGPU::V_WRITELANE_B32),
227                 Spill.VGPR)
228                 .addReg(SubReg)
229                 .addImm(Spill.Lane);
230 
231       }
232       MI->eraseFromParent();
233       break;
234     }
235 
236     // SGPR register restore
237     case AMDGPU::SI_SPILL_S512_RESTORE:
238     case AMDGPU::SI_SPILL_S256_RESTORE:
239     case AMDGPU::SI_SPILL_S128_RESTORE:
240     case AMDGPU::SI_SPILL_S64_RESTORE:
241     case AMDGPU::SI_SPILL_S32_RESTORE: {
242       unsigned NumSubRegs = getNumSubRegsForSpillOp(MI->getOpcode());
243 
244       for (unsigned i = 0, e = NumSubRegs; i < e; ++i) {
245         unsigned SubReg = getPhysRegSubReg(MI->getOperand(0).getReg(),
246                                            &AMDGPU::SGPR_32RegClass, i);
247         struct SIMachineFunctionInfo::SpilledReg Spill =
248             MFI->getSpilledReg(MF, Index, i);
249 
250         if (Spill.VGPR == AMDGPU::NoRegister) {
251            LLVMContext &Ctx = MF->getFunction()->getContext();
252            Ctx.emitError("Ran out of VGPRs for spilling SGPR");
253         }
254 
255         BuildMI(*MBB, MI, DL,
256                 TII->getMCOpcodeFromPseudo(AMDGPU::V_READLANE_B32),
257                 SubReg)
258                 .addReg(Spill.VGPR)
259                 .addImm(Spill.Lane)
260                 .addReg(MI->getOperand(0).getReg(), RegState::ImplicitDefine);
261       }
262 
263       // TODO: only do this when it is needed
264       switch (MF->getSubtarget<AMDGPUSubtarget>().getGeneration()) {
265       case AMDGPUSubtarget::SOUTHERN_ISLANDS:
266         // "VALU writes SGPR" -> "SMRD reads that SGPR" needs "S_NOP 3" on SI
267         TII->insertNOPs(MI, 3);
268         break;
269       case AMDGPUSubtarget::SEA_ISLANDS:
270         break;
271       default: // VOLCANIC_ISLANDS and later
272         // "VALU writes SGPR -> VMEM reads that SGPR" needs "S_NOP 4" on VI
273         // and later. This also applies to VALUs which write VCC, but we're
274         // unlikely to see VMEM use VCC.
275         TII->insertNOPs(MI, 4);
276       }
277 
278       MI->eraseFromParent();
279       break;
280     }
281 
282     // VGPR register spill
283     case AMDGPU::SI_SPILL_V512_SAVE:
284     case AMDGPU::SI_SPILL_V256_SAVE:
285     case AMDGPU::SI_SPILL_V128_SAVE:
286     case AMDGPU::SI_SPILL_V96_SAVE:
287     case AMDGPU::SI_SPILL_V64_SAVE:
288     case AMDGPU::SI_SPILL_V32_SAVE:
289       buildScratchLoadStore(MI, AMDGPU::BUFFER_STORE_DWORD_OFFSET,
290             TII->getNamedOperand(*MI, AMDGPU::OpName::src)->getReg(),
291             TII->getNamedOperand(*MI, AMDGPU::OpName::scratch_rsrc)->getReg(),
292             TII->getNamedOperand(*MI, AMDGPU::OpName::scratch_offset)->getReg(),
293              FrameInfo->getObjectOffset(Index), RS);
294       MI->eraseFromParent();
295       break;
296     case AMDGPU::SI_SPILL_V32_RESTORE:
297     case AMDGPU::SI_SPILL_V64_RESTORE:
298     case AMDGPU::SI_SPILL_V96_RESTORE:
299     case AMDGPU::SI_SPILL_V128_RESTORE:
300     case AMDGPU::SI_SPILL_V256_RESTORE:
301     case AMDGPU::SI_SPILL_V512_RESTORE: {
302       buildScratchLoadStore(MI, AMDGPU::BUFFER_LOAD_DWORD_OFFSET,
303             TII->getNamedOperand(*MI, AMDGPU::OpName::dst)->getReg(),
304             TII->getNamedOperand(*MI, AMDGPU::OpName::scratch_rsrc)->getReg(),
305             TII->getNamedOperand(*MI, AMDGPU::OpName::scratch_offset)->getReg(),
306             FrameInfo->getObjectOffset(Index), RS);
307       MI->eraseFromParent();
308       break;
309     }
310 
311     default: {
312       int64_t Offset = FrameInfo->getObjectOffset(Index);
313       FIOp.ChangeToImmediate(Offset);
314       if (!TII->isImmOperandLegal(MI, FIOperandNum, FIOp)) {
315         unsigned TmpReg = RS->scavengeRegister(&AMDGPU::VGPR_32RegClass, MI, SPAdj);
316         BuildMI(*MBB, MI, MI->getDebugLoc(),
317                 TII->get(AMDGPU::V_MOV_B32_e32), TmpReg)
318                 .addImm(Offset);
319         FIOp.ChangeToRegister(TmpReg, false, false, true);
320       }
321     }
322   }
323 }
324 
getCFGStructurizerRegClass(MVT VT) const325 const TargetRegisterClass * SIRegisterInfo::getCFGStructurizerRegClass(
326                                                                    MVT VT) const {
327   switch(VT.SimpleTy) {
328     default:
329     case MVT::i32: return &AMDGPU::VGPR_32RegClass;
330   }
331 }
332 
getHWRegIndex(unsigned Reg) const333 unsigned SIRegisterInfo::getHWRegIndex(unsigned Reg) const {
334   return getEncodingValue(Reg) & 0xff;
335 }
336 
getPhysRegClass(unsigned Reg) const337 const TargetRegisterClass *SIRegisterInfo::getPhysRegClass(unsigned Reg) const {
338   assert(!TargetRegisterInfo::isVirtualRegister(Reg));
339 
340   static const TargetRegisterClass *BaseClasses[] = {
341     &AMDGPU::VGPR_32RegClass,
342     &AMDGPU::SReg_32RegClass,
343     &AMDGPU::VReg_64RegClass,
344     &AMDGPU::SReg_64RegClass,
345     &AMDGPU::VReg_96RegClass,
346     &AMDGPU::VReg_128RegClass,
347     &AMDGPU::SReg_128RegClass,
348     &AMDGPU::VReg_256RegClass,
349     &AMDGPU::SReg_256RegClass,
350     &AMDGPU::VReg_512RegClass,
351     &AMDGPU::SReg_512RegClass
352   };
353 
354   for (const TargetRegisterClass *BaseClass : BaseClasses) {
355     if (BaseClass->contains(Reg)) {
356       return BaseClass;
357     }
358   }
359   return nullptr;
360 }
361 
hasVGPRs(const TargetRegisterClass * RC) const362 bool SIRegisterInfo::hasVGPRs(const TargetRegisterClass *RC) const {
363   return getCommonSubClass(&AMDGPU::VGPR_32RegClass, RC) ||
364          getCommonSubClass(&AMDGPU::VReg_64RegClass, RC) ||
365          getCommonSubClass(&AMDGPU::VReg_96RegClass, RC) ||
366          getCommonSubClass(&AMDGPU::VReg_128RegClass, RC) ||
367          getCommonSubClass(&AMDGPU::VReg_256RegClass, RC) ||
368          getCommonSubClass(&AMDGPU::VReg_512RegClass, RC);
369 }
370 
getEquivalentVGPRClass(const TargetRegisterClass * SRC) const371 const TargetRegisterClass *SIRegisterInfo::getEquivalentVGPRClass(
372                                          const TargetRegisterClass *SRC) const {
373     if (hasVGPRs(SRC)) {
374       return SRC;
375     } else if (SRC == &AMDGPU::SCCRegRegClass) {
376       return &AMDGPU::VCCRegRegClass;
377     } else if (getCommonSubClass(SRC, &AMDGPU::SGPR_32RegClass)) {
378       return &AMDGPU::VGPR_32RegClass;
379     } else if (getCommonSubClass(SRC, &AMDGPU::SGPR_64RegClass)) {
380       return &AMDGPU::VReg_64RegClass;
381     } else if (getCommonSubClass(SRC, &AMDGPU::SReg_128RegClass)) {
382       return &AMDGPU::VReg_128RegClass;
383     } else if (getCommonSubClass(SRC, &AMDGPU::SReg_256RegClass)) {
384       return &AMDGPU::VReg_256RegClass;
385     } else if (getCommonSubClass(SRC, &AMDGPU::SReg_512RegClass)) {
386       return &AMDGPU::VReg_512RegClass;
387     }
388     return nullptr;
389 }
390 
getSubRegClass(const TargetRegisterClass * RC,unsigned SubIdx) const391 const TargetRegisterClass *SIRegisterInfo::getSubRegClass(
392                          const TargetRegisterClass *RC, unsigned SubIdx) const {
393   if (SubIdx == AMDGPU::NoSubRegister)
394     return RC;
395 
396   // If this register has a sub-register, we can safely assume it is a 32-bit
397   // register, because all of SI's sub-registers are 32-bit.
398   if (isSGPRClass(RC)) {
399     return &AMDGPU::SGPR_32RegClass;
400   } else {
401     return &AMDGPU::VGPR_32RegClass;
402   }
403 }
404 
getPhysRegSubReg(unsigned Reg,const TargetRegisterClass * SubRC,unsigned Channel) const405 unsigned SIRegisterInfo::getPhysRegSubReg(unsigned Reg,
406                                           const TargetRegisterClass *SubRC,
407                                           unsigned Channel) const {
408 
409   switch (Reg) {
410     case AMDGPU::VCC:
411       switch(Channel) {
412         case 0: return AMDGPU::VCC_LO;
413         case 1: return AMDGPU::VCC_HI;
414         default: llvm_unreachable("Invalid SubIdx for VCC");
415       }
416 
417   case AMDGPU::FLAT_SCR:
418     switch (Channel) {
419     case 0:
420       return AMDGPU::FLAT_SCR_LO;
421     case 1:
422       return AMDGPU::FLAT_SCR_HI;
423     default:
424       llvm_unreachable("Invalid SubIdx for FLAT_SCR");
425     }
426     break;
427 
428   case AMDGPU::EXEC:
429     switch (Channel) {
430     case 0:
431       return AMDGPU::EXEC_LO;
432     case 1:
433       return AMDGPU::EXEC_HI;
434     default:
435       llvm_unreachable("Invalid SubIdx for EXEC");
436     }
437     break;
438   }
439 
440   const TargetRegisterClass *RC = getPhysRegClass(Reg);
441   // 32-bit registers don't have sub-registers, so we can just return the
442   // Reg.  We need to have this check here, because the calculation below
443   // using getHWRegIndex() will fail with special 32-bit registers like
444   // VCC_LO, VCC_HI, EXEC_LO, EXEC_HI and M0.
445   if (RC->getSize() == 4) {
446     assert(Channel == 0);
447     return Reg;
448   }
449 
450   unsigned Index = getHWRegIndex(Reg);
451   return SubRC->getRegister(Index + Channel);
452 }
453 
opCanUseLiteralConstant(unsigned OpType) const454 bool SIRegisterInfo::opCanUseLiteralConstant(unsigned OpType) const {
455   return OpType == AMDGPU::OPERAND_REG_IMM32;
456 }
457 
opCanUseInlineConstant(unsigned OpType) const458 bool SIRegisterInfo::opCanUseInlineConstant(unsigned OpType) const {
459   if (opCanUseLiteralConstant(OpType))
460     return true;
461 
462   return OpType == AMDGPU::OPERAND_REG_INLINE_C;
463 }
464 
getPreloadedValue(const MachineFunction & MF,enum PreloadedValue Value) const465 unsigned SIRegisterInfo::getPreloadedValue(const MachineFunction &MF,
466                                            enum PreloadedValue Value) const {
467 
468   const SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
469   switch (Value) {
470   case SIRegisterInfo::TGID_X:
471     return AMDGPU::SReg_32RegClass.getRegister(MFI->NumUserSGPRs + 0);
472   case SIRegisterInfo::TGID_Y:
473     return AMDGPU::SReg_32RegClass.getRegister(MFI->NumUserSGPRs + 1);
474   case SIRegisterInfo::TGID_Z:
475     return AMDGPU::SReg_32RegClass.getRegister(MFI->NumUserSGPRs + 2);
476   case SIRegisterInfo::SCRATCH_WAVE_OFFSET:
477     if (MFI->getShaderType() != ShaderType::COMPUTE)
478       return MFI->ScratchOffsetReg;
479     return AMDGPU::SReg_32RegClass.getRegister(MFI->NumUserSGPRs + 4);
480   case SIRegisterInfo::SCRATCH_PTR:
481     return AMDGPU::SGPR2_SGPR3;
482   case SIRegisterInfo::INPUT_PTR:
483     return AMDGPU::SGPR0_SGPR1;
484   case SIRegisterInfo::TIDIG_X:
485     return AMDGPU::VGPR0;
486   case SIRegisterInfo::TIDIG_Y:
487     return AMDGPU::VGPR1;
488   case SIRegisterInfo::TIDIG_Z:
489     return AMDGPU::VGPR2;
490   }
491   llvm_unreachable("unexpected preloaded value type");
492 }
493 
494 /// \brief Returns a register that is not used at any point in the function.
495 ///        If all registers are used, then this function will return
496 //         AMDGPU::NoRegister.
findUnusedRegister(const MachineRegisterInfo & MRI,const TargetRegisterClass * RC) const497 unsigned SIRegisterInfo::findUnusedRegister(const MachineRegisterInfo &MRI,
498                                            const TargetRegisterClass *RC) const {
499 
500   for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
501        I != E; ++I) {
502     if (!MRI.isPhysRegUsed(*I))
503       return *I;
504   }
505   return AMDGPU::NoRegister;
506 }
507 
getNumVGPRsAllowed(unsigned WaveCount) const508 unsigned SIRegisterInfo::getNumVGPRsAllowed(unsigned WaveCount) const {
509   switch(WaveCount) {
510     case 10: return 24;
511     case 9:  return 28;
512     case 8:  return 32;
513     case 7:  return 36;
514     case 6:  return 40;
515     case 5:  return 48;
516     case 4:  return 64;
517     case 3:  return 84;
518     case 2:  return 128;
519     default: return 256;
520   }
521 }
522 
getNumSGPRsAllowed(AMDGPUSubtarget::Generation gen,unsigned WaveCount) const523 unsigned SIRegisterInfo::getNumSGPRsAllowed(AMDGPUSubtarget::Generation gen,
524                                             unsigned WaveCount) const {
525   if (gen >= AMDGPUSubtarget::VOLCANIC_ISLANDS) {
526     switch (WaveCount) {
527       case 10: return 80;
528       case 9:  return 80;
529       case 8:  return 96;
530       default: return 102;
531     }
532   } else {
533     switch(WaveCount) {
534       case 10: return 48;
535       case 9:  return 56;
536       case 8:  return 64;
537       case 7:  return 72;
538       case 6:  return 80;
539       case 5:  return 96;
540       default: return 103;
541     }
542   }
543 }
544