1 //===-- NEONPreAllocPass.cpp - Allocate adjacent NEON registers--*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #define DEBUG_TYPE "neon-prealloc"
12 #include "ARMInstrInfo.h"
13 #include "llvm/CodeGen/MachineInstr.h"
14 #include "llvm/CodeGen/MachineInstrBuilder.h"
15 #include "llvm/CodeGen/MachineRegisterInfo.h"
16 #include "llvm/CodeGen/MachineFunctionPass.h"
20 class NEONPreAllocPass : public MachineFunctionPass {
21 const TargetInstrInfo *TII;
22 MachineRegisterInfo *MRI;
26 NEONPreAllocPass() : MachineFunctionPass(&ID) {}
28 virtual bool runOnMachineFunction(MachineFunction &MF);
30 virtual const char *getPassName() const {
31 return "NEON register pre-allocation pass";
35 bool FormsRegSequence(MachineInstr *MI,
36 unsigned FirstOpnd, unsigned NumRegs);
37 bool PreAllocNEONRegisters(MachineBasicBlock &MBB);
40 char NEONPreAllocPass::ID = 0;
43 static bool isNEONMultiRegOp(int Opcode, unsigned &FirstOpnd, unsigned &NumRegs,
44 unsigned &Offset, unsigned &Stride) {
45 // Default to unit stride with no offset.
82 case ARM::VLD2LNq16odd:
83 case ARM::VLD2LNq32odd:
101 case ARM::VLD3q8_UPD:
102 case ARM::VLD3q16_UPD:
103 case ARM::VLD3q32_UPD:
110 case ARM::VLD3q8odd_UPD:
111 case ARM::VLD3q16odd_UPD:
112 case ARM::VLD3q32odd_UPD:
127 case ARM::VLD3LNq16odd:
128 case ARM::VLD3LNq32odd:
146 case ARM::VLD4q8_UPD:
147 case ARM::VLD4q16_UPD:
148 case ARM::VLD4q32_UPD:
155 case ARM::VLD4q8odd_UPD:
156 case ARM::VLD4q16odd_UPD:
157 case ARM::VLD4q32odd_UPD:
172 case ARM::VLD4LNq16odd:
173 case ARM::VLD4LNq32odd:
209 case ARM::VST2LNq16odd:
210 case ARM::VST2LNq32odd:
228 case ARM::VST3q8_UPD:
229 case ARM::VST3q16_UPD:
230 case ARM::VST3q32_UPD:
237 case ARM::VST3q8odd_UPD:
238 case ARM::VST3q16odd_UPD:
239 case ARM::VST3q32odd_UPD:
254 case ARM::VST3LNq16odd:
255 case ARM::VST3LNq32odd:
273 case ARM::VST4q8_UPD:
274 case ARM::VST4q16_UPD:
275 case ARM::VST4q32_UPD:
282 case ARM::VST4q8odd_UPD:
283 case ARM::VST4q16odd_UPD:
284 case ARM::VST4q32odd_UPD:
299 case ARM::VST4LNq16odd:
300 case ARM::VST4LNq32odd:
341 bool NEONPreAllocPass::FormsRegSequence(MachineInstr *MI,
342 unsigned FirstOpnd, unsigned NumRegs) {
343 MachineInstr *RegSeq = 0;
344 unsigned LastSrcReg = 0;
345 unsigned LastSubIdx = 0;
346 for (unsigned R = 0; R < NumRegs; ++R) {
347 MachineOperand &MO = MI->getOperand(FirstOpnd + R);
348 assert(MO.isReg() && MO.getSubReg() == 0 && "unexpected operand");
349 unsigned VirtReg = MO.getReg();
350 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
351 "expected a virtual register");
353 // Feeding into a REG_SEQUENCE.
354 if (!MRI->hasOneNonDBGUse(VirtReg))
356 MachineInstr *UseMI = &*MRI->use_nodbg_begin(VirtReg);
357 if (!UseMI->isRegSequence())
359 if (RegSeq && RegSeq != UseMI)
363 // Extracting from a Q register.
364 MachineInstr *DefMI = MRI->getVRegDef(VirtReg);
365 if (!DefMI || !DefMI->isExtractSubreg())
367 VirtReg = DefMI->getOperand(1).getReg();
368 if (LastSrcReg && LastSrcReg != VirtReg)
370 const TargetRegisterClass *RC = MRI->getRegClass(VirtReg);
371 if (RC != ARM::QPRRegisterClass)
373 unsigned SubIdx = DefMI->getOperand(2).getImm();
374 if (LastSubIdx && LastSubIdx != SubIdx-1)
382 bool NEONPreAllocPass::PreAllocNEONRegisters(MachineBasicBlock &MBB) {
383 bool Modified = false;
385 MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();
386 for (; MBBI != E; ++MBBI) {
387 MachineInstr *MI = &*MBBI;
388 unsigned FirstOpnd, NumRegs, Offset, Stride;
389 if (!isNEONMultiRegOp(MI->getOpcode(), FirstOpnd, NumRegs, Offset, Stride))
391 if (FormsRegSequence(MI, FirstOpnd, NumRegs))
394 MachineBasicBlock::iterator NextI = llvm::next(MBBI);
395 for (unsigned R = 0; R < NumRegs; ++R) {
396 MachineOperand &MO = MI->getOperand(FirstOpnd + R);
397 assert(MO.isReg() && MO.getSubReg() == 0 && "unexpected operand");
398 unsigned VirtReg = MO.getReg();
399 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
400 "expected a virtual register");
402 // For now, just assign a fixed set of adjacent registers.
403 // This leaves plenty of room for future improvements.
404 static const unsigned NEONDRegs[] = {
405 ARM::D0, ARM::D1, ARM::D2, ARM::D3,
406 ARM::D4, ARM::D5, ARM::D6, ARM::D7
408 MO.setReg(NEONDRegs[Offset + R * Stride]);
411 // Insert a copy from VirtReg.
412 TII->copyRegToReg(MBB, MBBI, MO.getReg(), VirtReg,
413 ARM::DPRRegisterClass, ARM::DPRRegisterClass,
416 MachineInstr *CopyMI = prior(MBBI);
417 CopyMI->findRegisterUseOperand(VirtReg)->setIsKill();
420 } else if (MO.isDef() && !MO.isDead()) {
421 // Add a copy to VirtReg.
422 TII->copyRegToReg(MBB, NextI, VirtReg, MO.getReg(),
423 ARM::DPRRegisterClass, ARM::DPRRegisterClass,
432 bool NEONPreAllocPass::runOnMachineFunction(MachineFunction &MF) {
433 TII = MF.getTarget().getInstrInfo();
434 MRI = &MF.getRegInfo();
436 bool Modified = false;
437 for (MachineFunction::iterator MFI = MF.begin(), E = MF.end(); MFI != E;
439 MachineBasicBlock &MBB = *MFI;
440 Modified |= PreAllocNEONRegisters(MBB);
446 /// createNEONPreAllocPass - returns an instance of the NEON register
447 /// pre-allocation pass.
448 FunctionPass *llvm::createNEONPreAllocPass() {
449 return new NEONPreAllocPass();