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/MachineFunctionPass.h"
19 class VISIBILITY_HIDDEN NEONPreAllocPass : public MachineFunctionPass {
20 const TargetInstrInfo *TII;
24 NEONPreAllocPass() : MachineFunctionPass(&ID) {}
26 virtual bool runOnMachineFunction(MachineFunction &MF);
28 virtual const char *getPassName() const {
29 return "NEON register pre-allocation pass";
33 bool PreAllocNEONRegisters(MachineBasicBlock &MBB);
36 char NEONPreAllocPass::ID = 0;
39 static bool isNEONMultiRegOp(int Opcode, unsigned &FirstOpnd, unsigned &NumRegs,
40 unsigned &Offset, unsigned &Stride) {
41 // Default to unit stride with no offset.
112 case ARM::VLD3LNq16a:
113 case ARM::VLD3LNq32a:
120 case ARM::VLD3LNq16b:
121 case ARM::VLD3LNq32b:
267 bool NEONPreAllocPass::PreAllocNEONRegisters(MachineBasicBlock &MBB) {
268 bool Modified = false;
270 MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();
271 for (; MBBI != E; ++MBBI) {
272 MachineInstr *MI = &*MBBI;
273 unsigned FirstOpnd, NumRegs, Offset, Stride;
274 if (!isNEONMultiRegOp(MI->getOpcode(), FirstOpnd, NumRegs, Offset, Stride))
277 MachineBasicBlock::iterator NextI = next(MBBI);
278 for (unsigned R = 0; R < NumRegs; ++R) {
279 MachineOperand &MO = MI->getOperand(FirstOpnd + R);
280 assert(MO.isReg() && MO.getSubReg() == 0 && "unexpected operand");
281 unsigned VirtReg = MO.getReg();
282 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
283 "expected a virtual register");
285 // For now, just assign a fixed set of adjacent registers.
286 // This leaves plenty of room for future improvements.
287 static const unsigned NEONDRegs[] = {
288 ARM::D0, ARM::D1, ARM::D2, ARM::D3,
289 ARM::D4, ARM::D5, ARM::D6, ARM::D7
291 MO.setReg(NEONDRegs[Offset + R * Stride]);
294 // Insert a copy from VirtReg.
295 TII->copyRegToReg(MBB, MBBI, MO.getReg(), VirtReg,
296 ARM::DPRRegisterClass, ARM::DPRRegisterClass);
298 MachineInstr *CopyMI = prior(MBBI);
299 CopyMI->findRegisterUseOperand(VirtReg)->setIsKill();
302 } else if (MO.isDef() && !MO.isDead()) {
303 // Add a copy to VirtReg.
304 TII->copyRegToReg(MBB, NextI, VirtReg, MO.getReg(),
305 ARM::DPRRegisterClass, ARM::DPRRegisterClass);
313 bool NEONPreAllocPass::runOnMachineFunction(MachineFunction &MF) {
314 TII = MF.getTarget().getInstrInfo();
316 bool Modified = false;
317 for (MachineFunction::iterator MFI = MF.begin(), E = MF.end(); MFI != E;
319 MachineBasicBlock &MBB = *MFI;
320 Modified |= PreAllocNEONRegisters(MBB);
326 /// createNEONPreAllocPass - returns an instance of the NEON register
327 /// pre-allocation pass.
328 FunctionPass *llvm::createNEONPreAllocPass() {
329 return new NEONPreAllocPass();