1 //===-- RegAllocLocal.cpp - A BasicBlock generic register allocator -------===//
3 // This register allocator allocates registers to a basic block at a time,
4 // attempting to keep values in registers and reusing registers as appropriate.
6 //===----------------------------------------------------------------------===//
8 #define DEBUG_TYPE "regalloc"
9 #include "llvm/CodeGen/Passes.h"
10 #include "llvm/CodeGen/MachineFunctionPass.h"
11 #include "llvm/CodeGen/MachineInstr.h"
12 #include "llvm/CodeGen/SSARegMap.h"
13 #include "llvm/CodeGen/MachineFrameInfo.h"
14 #include "llvm/CodeGen/LiveVariables.h"
15 #include "llvm/Target/TargetInstrInfo.h"
16 #include "llvm/Target/TargetMachine.h"
17 #include "Support/CommandLine.h"
18 #include "Support/Debug.h"
19 #include "Support/Statistic.h"
23 Statistic<> NumSpilled ("ra-local", "Number of registers spilled");
24 Statistic<> NumReloaded("ra-local", "Number of registers reloaded");
25 cl::opt<bool> DisableKill("no-kill", cl::Hidden,
26 cl::desc("Disable register kill in local-ra"));
28 class RA : public MachineFunctionPass {
29 const TargetMachine *TM;
31 const MRegisterInfo *RegInfo;
34 // StackSlotForVirtReg - Maps virtual regs to the frame index where these
35 // values are spilled.
36 std::map<unsigned, int> StackSlotForVirtReg;
38 // Virt2PhysRegMap - This map contains entries for each virtual register
39 // that is currently available in a physical register.
41 std::map<unsigned, unsigned> Virt2PhysRegMap;
43 // PhysRegsUsed - This map contains entries for each physical register that
44 // currently has a value (ie, it is in Virt2PhysRegMap). The value mapped
45 // to is the virtual register corresponding to the physical register (the
46 // inverse of the Virt2PhysRegMap), or 0. The value is set to 0 if this
47 // register is pinned because it is used by a future instruction.
49 std::map<unsigned, unsigned> PhysRegsUsed;
51 // PhysRegsUseOrder - This contains a list of the physical registers that
52 // currently have a virtual register value in them. This list provides an
53 // ordering of registers, imposing a reallocation order. This list is only
54 // used if all registers are allocated and we have to spill one, in which
55 // case we spill the least recently used register. Entries at the front of
56 // the list are the least recently used registers, entries at the back are
57 // the most recently used.
59 std::vector<unsigned> PhysRegsUseOrder;
61 // VirtRegModified - This bitset contains information about which virtual
62 // registers need to be spilled back to memory when their registers are
63 // scavenged. If a virtual register has simply been rematerialized, there
64 // is no reason to spill it to memory when we need the register back.
66 std::vector<bool> VirtRegModified;
68 void markVirtRegModified(unsigned Reg, bool Val = true) {
69 assert(Reg >= MRegisterInfo::FirstVirtualRegister && "Illegal VirtReg!");
70 Reg -= MRegisterInfo::FirstVirtualRegister;
71 if (VirtRegModified.size() <= Reg) VirtRegModified.resize(Reg+1);
72 VirtRegModified[Reg] = Val;
75 bool isVirtRegModified(unsigned Reg) const {
76 assert(Reg >= MRegisterInfo::FirstVirtualRegister && "Illegal VirtReg!");
77 assert(Reg - MRegisterInfo::FirstVirtualRegister < VirtRegModified.size()
78 && "Illegal virtual register!");
79 return VirtRegModified[Reg - MRegisterInfo::FirstVirtualRegister];
82 void MarkPhysRegRecentlyUsed(unsigned Reg) {
83 assert(!PhysRegsUseOrder.empty() && "No registers used!");
84 if (PhysRegsUseOrder.back() == Reg) return; // Already most recently used
86 for (unsigned i = PhysRegsUseOrder.size(); i != 0; --i)
87 if (areRegsEqual(Reg, PhysRegsUseOrder[i-1])) {
88 unsigned RegMatch = PhysRegsUseOrder[i-1]; // remove from middle
89 PhysRegsUseOrder.erase(PhysRegsUseOrder.begin()+i-1);
90 // Add it to the end of the list
91 PhysRegsUseOrder.push_back(RegMatch);
93 return; // Found an exact match, exit early
98 virtual const char *getPassName() const {
99 return "Local Register Allocator";
102 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
104 AU.addRequired<LiveVariables>();
105 AU.addRequiredID(PHIEliminationID);
106 MachineFunctionPass::getAnalysisUsage(AU);
110 /// runOnMachineFunction - Register allocate the whole function
111 bool runOnMachineFunction(MachineFunction &Fn);
113 /// AllocateBasicBlock - Register allocate the specified basic block.
114 void AllocateBasicBlock(MachineBasicBlock &MBB);
117 /// areRegsEqual - This method returns true if the specified registers are
118 /// related to each other. To do this, it checks to see if they are equal
119 /// or if the first register is in the alias set of the second register.
121 bool areRegsEqual(unsigned R1, unsigned R2) const {
122 if (R1 == R2) return true;
123 if (const unsigned *AliasSet = RegInfo->getAliasSet(R2))
124 for (unsigned i = 0; AliasSet[i]; ++i)
125 if (AliasSet[i] == R1) return true;
129 /// getStackSpaceFor - This returns the frame index of the specified virtual
130 /// register on the stack, allocating space if necessary.
131 int getStackSpaceFor(unsigned VirtReg, const TargetRegisterClass *RC);
133 /// removePhysReg - This method marks the specified physical register as no
134 /// longer being in use.
136 void removePhysReg(unsigned PhysReg);
138 /// spillVirtReg - This method spills the value specified by PhysReg into
139 /// the virtual register slot specified by VirtReg. It then updates the RA
140 /// data structures to indicate the fact that PhysReg is now available.
142 void spillVirtReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
143 unsigned VirtReg, unsigned PhysReg);
145 /// spillPhysReg - This method spills the specified physical register into
146 /// the virtual register slot associated with it.
148 void spillPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
151 /// assignVirtToPhysReg - This method updates local state so that we know
152 /// that PhysReg is the proper container for VirtReg now. The physical
153 /// register must not be used for anything else when this is called.
155 void assignVirtToPhysReg(unsigned VirtReg, unsigned PhysReg);
157 /// liberatePhysReg - Make sure the specified physical register is available
158 /// for use. If there is currently a value in it, it is either moved out of
159 /// the way or spilled to memory.
161 void liberatePhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
164 /// isPhysRegAvailable - Return true if the specified physical register is
165 /// free and available for use. This also includes checking to see if
166 /// aliased registers are all free...
168 bool isPhysRegAvailable(unsigned PhysReg) const;
170 /// getFreeReg - Look to see if there is a free register available in the
171 /// specified register class. If not, return 0.
173 unsigned getFreeReg(const TargetRegisterClass *RC);
175 /// getReg - Find a physical register to hold the specified virtual
176 /// register. If all compatible physical registers are used, this method
177 /// spills the last used virtual register to the stack, and uses that
180 unsigned getReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
183 /// reloadVirtReg - This method loads the specified virtual register into a
184 /// physical register, returning the physical register chosen. This updates
185 /// the regalloc data structures to reflect the fact that the virtual reg is
186 /// now alive in a physical register, and the previous one isn't.
188 unsigned reloadVirtReg(MachineBasicBlock &MBB,
189 MachineBasicBlock::iterator &I, unsigned VirtReg);
191 void reloadPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
197 /// getStackSpaceFor - This allocates space for the specified virtual register
198 /// to be held on the stack.
199 int RA::getStackSpaceFor(unsigned VirtReg, const TargetRegisterClass *RC) {
200 // Find the location Reg would belong...
201 std::map<unsigned, int>::iterator I =StackSlotForVirtReg.lower_bound(VirtReg);
203 if (I != StackSlotForVirtReg.end() && I->first == VirtReg)
204 return I->second; // Already has space allocated?
206 // Allocate a new stack object for this spill location...
207 int FrameIdx = MF->getFrameInfo()->CreateStackObject(RC);
209 // Assign the slot...
210 StackSlotForVirtReg.insert(I, std::make_pair(VirtReg, FrameIdx));
215 /// removePhysReg - This method marks the specified physical register as no
216 /// longer being in use.
218 void RA::removePhysReg(unsigned PhysReg) {
219 PhysRegsUsed.erase(PhysReg); // PhyReg no longer used
221 std::vector<unsigned>::iterator It =
222 std::find(PhysRegsUseOrder.begin(), PhysRegsUseOrder.end(), PhysReg);
223 assert(It != PhysRegsUseOrder.end() &&
224 "Spilled a physical register, but it was not in use list!");
225 PhysRegsUseOrder.erase(It);
229 /// spillVirtReg - This method spills the value specified by PhysReg into the
230 /// virtual register slot specified by VirtReg. It then updates the RA data
231 /// structures to indicate the fact that PhysReg is now available.
233 void RA::spillVirtReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
234 unsigned VirtReg, unsigned PhysReg) {
236 DEBUG(std::cerr << " Spilling register " << RegInfo->getName(PhysReg));
238 DEBUG(std::cerr << " which corresponds to no vreg, "
239 << "must be spurious physreg: ignoring (WARNING)\n");
241 DEBUG(std::cerr << " containing %reg" << VirtReg;
242 if (!isVirtRegModified(VirtReg))
243 std::cerr << " which has not been modified, so no store necessary!");
245 // Otherwise, there is a virtual register corresponding to this physical
246 // register. We only need to spill it into its stack slot if it has been
248 if (isVirtRegModified(VirtReg)) {
249 const TargetRegisterClass *RC = MF->getSSARegMap()->getRegClass(VirtReg);
250 int FrameIndex = getStackSpaceFor(VirtReg, RC);
251 DEBUG(std::cerr << " to stack slot #" << FrameIndex);
252 RegInfo->storeRegToStackSlot(MBB, I, PhysReg, FrameIndex, RC);
253 ++NumSpilled; // Update statistics
255 Virt2PhysRegMap.erase(VirtReg); // VirtReg no longer available
258 DEBUG(std::cerr << "\n");
259 removePhysReg(PhysReg);
263 /// spillPhysReg - This method spills the specified physical register into the
264 /// virtual register slot associated with it.
266 void RA::spillPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
268 std::map<unsigned, unsigned>::iterator PI = PhysRegsUsed.find(PhysReg);
269 if (PI != PhysRegsUsed.end()) { // Only spill it if it's used!
270 spillVirtReg(MBB, I, PI->second, PhysReg);
271 } else if (const unsigned *AliasSet = RegInfo->getAliasSet(PhysReg)) {
272 // If the selected register aliases any other registers, we must make
273 // sure that one of the aliases isn't alive...
274 for (unsigned i = 0; AliasSet[i]; ++i) {
275 PI = PhysRegsUsed.find(AliasSet[i]);
276 if (PI != PhysRegsUsed.end()) // Spill aliased register...
277 spillVirtReg(MBB, I, PI->second, AliasSet[i]);
283 /// assignVirtToPhysReg - This method updates local state so that we know
284 /// that PhysReg is the proper container for VirtReg now. The physical
285 /// register must not be used for anything else when this is called.
287 void RA::assignVirtToPhysReg(unsigned VirtReg, unsigned PhysReg) {
288 assert(PhysRegsUsed.find(PhysReg) == PhysRegsUsed.end() &&
289 "Phys reg already assigned!");
290 // Update information to note the fact that this register was just used, and
292 PhysRegsUsed[PhysReg] = VirtReg;
293 Virt2PhysRegMap[VirtReg] = PhysReg;
294 PhysRegsUseOrder.push_back(PhysReg); // New use of PhysReg
298 /// isPhysRegAvailable - Return true if the specified physical register is free
299 /// and available for use. This also includes checking to see if aliased
300 /// registers are all free...
302 bool RA::isPhysRegAvailable(unsigned PhysReg) const {
303 if (PhysRegsUsed.count(PhysReg)) return false;
305 // If the selected register aliases any other allocated registers, it is
307 if (const unsigned *AliasSet = RegInfo->getAliasSet(PhysReg))
308 for (unsigned i = 0; AliasSet[i]; ++i)
309 if (PhysRegsUsed.count(AliasSet[i])) // Aliased register in use?
310 return false; // Can't use this reg then.
315 /// getFreeReg - Look to see if there is a free register available in the
316 /// specified register class. If not, return 0.
318 unsigned RA::getFreeReg(const TargetRegisterClass *RC) {
319 // Get iterators defining the range of registers that are valid to allocate in
320 // this class, which also specifies the preferred allocation order.
321 TargetRegisterClass::iterator RI = RC->allocation_order_begin(*MF);
322 TargetRegisterClass::iterator RE = RC->allocation_order_end(*MF);
324 for (; RI != RE; ++RI)
325 if (isPhysRegAvailable(*RI)) { // Is reg unused?
326 assert(*RI != 0 && "Cannot use register!");
327 return *RI; // Found an unused register!
333 /// liberatePhysReg - Make sure the specified physical register is available for
334 /// use. If there is currently a value in it, it is either moved out of the way
335 /// or spilled to memory.
337 void RA::liberatePhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
339 // FIXME: This code checks to see if a register is available, but it really
340 // wants to know if a reg is available BEFORE the instruction executes. If
341 // called after killed operands are freed, it runs the risk of reallocating a
344 if (isPhysRegAvailable(PhysReg)) return; // Already available...
346 // Check to see if the register is directly used, not indirectly used through
347 // aliases. If aliased registers are the ones actually used, we cannot be
348 // sure that we will be able to save the whole thing if we do a reg-reg copy.
349 std::map<unsigned, unsigned>::iterator PRUI = PhysRegsUsed.find(PhysReg);
350 if (PRUI != PhysRegsUsed.end()) {
351 unsigned VirtReg = PRUI->second; // The virtual register held...
353 // Check to see if there is a compatible register available. If so, we can
354 // move the value into the new register...
356 const TargetRegisterClass *RC = RegInfo->getRegClass(PhysReg);
357 if (unsigned NewReg = getFreeReg(RC)) {
358 // Emit the code to copy the value...
359 RegInfo->copyRegToReg(MBB, I, NewReg, PhysReg, RC);
361 // Update our internal state to indicate that PhysReg is available and Reg
363 Virt2PhysRegMap.erase(VirtReg);
364 removePhysReg(PhysReg); // Free the physreg
366 // Move reference over to new register...
367 assignVirtToPhysReg(VirtReg, NewReg);
372 spillPhysReg(MBB, I, PhysReg);
376 /// getReg - Find a physical register to hold the specified virtual
377 /// register. If all compatible physical registers are used, this method spills
378 /// the last used virtual register to the stack, and uses that register.
380 unsigned RA::getReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
382 const TargetRegisterClass *RC = MF->getSSARegMap()->getRegClass(VirtReg);
384 // First check to see if we have a free register of the requested type...
385 unsigned PhysReg = getFreeReg(RC);
387 // If we didn't find an unused register, scavenge one now!
389 assert(!PhysRegsUseOrder.empty() && "No allocated registers??");
391 // Loop over all of the preallocated registers from the least recently used
392 // to the most recently used. When we find one that is capable of holding
393 // our register, use it.
394 for (unsigned i = 0; PhysReg == 0; ++i) {
395 assert(i != PhysRegsUseOrder.size() &&
396 "Couldn't find a register of the appropriate class!");
398 unsigned R = PhysRegsUseOrder[i];
399 // If the current register is compatible, use it.
400 if (RegInfo->getRegClass(R) == RC) {
404 // If one of the registers aliased to the current register is
405 // compatible, use it.
406 if (const unsigned *AliasSet = RegInfo->getAliasSet(R))
407 for (unsigned a = 0; AliasSet[a]; ++a)
408 if (RegInfo->getRegClass(AliasSet[a]) == RC) {
409 PhysReg = AliasSet[a]; // Take an aliased register
415 assert(PhysReg && "Physical register not assigned!?!?");
417 // At this point PhysRegsUseOrder[i] is the least recently used register of
418 // compatible register class. Spill it to memory and reap its remains.
419 spillPhysReg(MBB, I, PhysReg);
422 // Now that we know which register we need to assign this to, do it now!
423 assignVirtToPhysReg(VirtReg, PhysReg);
428 /// reloadVirtReg - This method loads the specified virtual register into a
429 /// physical register, returning the physical register chosen. This updates the
430 /// regalloc data structures to reflect the fact that the virtual reg is now
431 /// alive in a physical register, and the previous one isn't.
433 unsigned RA::reloadVirtReg(MachineBasicBlock &MBB,
434 MachineBasicBlock::iterator &I,
436 std::map<unsigned, unsigned>::iterator It = Virt2PhysRegMap.find(VirtReg);
437 if (It != Virt2PhysRegMap.end()) {
438 MarkPhysRegRecentlyUsed(It->second);
439 return It->second; // Already have this value available!
442 unsigned PhysReg = getReg(MBB, I, VirtReg);
444 const TargetRegisterClass *RC = MF->getSSARegMap()->getRegClass(VirtReg);
445 int FrameIndex = getStackSpaceFor(VirtReg, RC);
447 markVirtRegModified(VirtReg, false); // Note that this reg was just reloaded
449 DEBUG(std::cerr << " Reloading %reg" << VirtReg << " into "
450 << RegInfo->getName(PhysReg) << "\n");
452 // Add move instruction(s)
453 RegInfo->loadRegFromStackSlot(MBB, I, PhysReg, FrameIndex, RC);
454 ++NumReloaded; // Update statistics
460 void RA::AllocateBasicBlock(MachineBasicBlock &MBB) {
461 // loop over each instruction
462 MachineBasicBlock::iterator I = MBB.begin();
463 for (; I != MBB.end(); ++I) {
464 MachineInstr *MI = *I;
465 const TargetInstrDescriptor &TID = TM->getInstrInfo().get(MI->getOpcode());
466 DEBUG(std::cerr << "\nStarting RegAlloc of: " << *MI;
467 std::cerr << " Regs have values: ";
468 for (std::map<unsigned, unsigned>::const_iterator
469 I = PhysRegsUsed.begin(), E = PhysRegsUsed.end(); I != E; ++I)
470 std::cerr << "[" << RegInfo->getName(I->first)
471 << ",%reg" << I->second << "] ";
474 // Loop over the implicit uses, making sure that they are at the head of the
475 // use order list, so they don't get reallocated.
476 if (const unsigned *ImplicitUses = TID.ImplicitUses)
477 for (unsigned i = 0; ImplicitUses[i]; ++i)
478 MarkPhysRegRecentlyUsed(ImplicitUses[i]);
480 // Get the used operands into registers. This has the potiential to spill
481 // incoming values if we are out of registers. Note that we completely
482 // ignore physical register uses here. We assume that if an explicit
483 // physical register is referenced by the instruction, that it is guaranteed
484 // to be live-in, or the input is badly hosed.
486 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
487 if (MI->getOperand(i).opIsUse() && MI->getOperand(i).isVirtualRegister()){
488 unsigned VirtSrcReg = MI->getOperand(i).getAllocatedRegNum();
489 unsigned PhysSrcReg = reloadVirtReg(MBB, I, VirtSrcReg);
490 MI->SetMachineOperandReg(i, PhysSrcReg); // Assign the input register
494 // If this instruction is the last user of anything in registers, kill the
495 // value, freeing the register being used, so it doesn't need to be
496 // spilled to memory.
498 for (LiveVariables::killed_iterator KI = LV->killed_begin(MI),
499 KE = LV->killed_end(MI); KI != KE; ++KI) {
500 unsigned VirtReg = KI->second;
501 unsigned PhysReg = VirtReg;
502 if (VirtReg >= MRegisterInfo::FirstVirtualRegister) {
503 std::map<unsigned, unsigned>::iterator I =
504 Virt2PhysRegMap.find(VirtReg);
505 assert(I != Virt2PhysRegMap.end());
507 Virt2PhysRegMap.erase(I);
511 DEBUG(std::cerr << " Last use of " << RegInfo->getName(PhysReg)
512 << "[%reg" << VirtReg <<"], removing it from live set\n");
513 // If the physical register was used, but there was no definition of
514 // the physical register (we are reading garbage), Live Variables will
515 // tell us that this is the last use of the register even though we
516 // don't know of anything in the register. No need to remove it.
517 if (VirtReg != PhysReg || PhysRegsUsed.count(PhysReg))
518 removePhysReg(PhysReg);
523 // Loop over all of the operands of the instruction, spilling registers that
524 // are defined, and marking explicit destinations in the PhysRegsUsed map.
525 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
526 if ((MI->getOperand(i).opIsDefOnly() ||
527 MI->getOperand(i).opIsDefAndUse()) &&
528 MI->getOperand(i).isPhysicalRegister()) {
529 unsigned Reg = MI->getOperand(i).getAllocatedRegNum();
530 spillPhysReg(MBB, I, Reg); // Spill any existing value in the reg
531 PhysRegsUsed[Reg] = 0; // It is free and reserved now
532 PhysRegsUseOrder.push_back(Reg);
535 // Loop over the implicit defs, spilling them as well.
536 if (const unsigned *ImplicitDefs = TID.ImplicitDefs)
537 for (unsigned i = 0; ImplicitDefs[i]; ++i) {
538 unsigned Reg = ImplicitDefs[i];
539 spillPhysReg(MBB, I, Reg);
540 PhysRegsUseOrder.push_back(Reg);
541 PhysRegsUsed[Reg] = 0; // It is free and reserved now
544 // Okay, we have allocated all of the source operands and spilled any values
545 // that would be destroyed by defs of this instruction. Loop over the
546 // implicit defs and assign them to a register, spilling incoming values if
547 // we need to scavenge a register.
549 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
550 if ((MI->getOperand(i).opIsDefOnly() || MI->getOperand(i).opIsDefAndUse())
551 && MI->getOperand(i).isVirtualRegister()) {
552 unsigned DestVirtReg = MI->getOperand(i).getAllocatedRegNum();
553 unsigned DestPhysReg;
555 // If DestVirtReg already has a value, forget about it. Why doesn't
556 // getReg do this right?
557 std::map<unsigned, unsigned>::iterator DestI =
558 Virt2PhysRegMap.find(DestVirtReg);
559 if (DestI != Virt2PhysRegMap.end()) {
560 unsigned PhysReg = DestI->second;
561 Virt2PhysRegMap.erase(DestI);
562 removePhysReg(PhysReg);
565 if (TM->getInstrInfo().isTwoAddrInstr(MI->getOpcode()) && i == 0) {
566 // must be same register number as the first operand
567 // This maps a = b + c into b += c, and saves b into a's spot
568 assert(MI->getOperand(1).isRegister() &&
569 MI->getOperand(1).getAllocatedRegNum() &&
570 MI->getOperand(1).opIsUse() &&
571 "Two address instruction invalid!");
572 DestPhysReg = MI->getOperand(1).getAllocatedRegNum();
574 liberatePhysReg(MBB, I, DestPhysReg);
575 assignVirtToPhysReg(DestVirtReg, DestPhysReg);
577 DestPhysReg = getReg(MBB, I, DestVirtReg);
579 markVirtRegModified(DestVirtReg);
580 MI->SetMachineOperandReg(i, DestPhysReg); // Assign the output register
584 // If this instruction defines any registers that are immediately dead,
587 for (LiveVariables::killed_iterator KI = LV->dead_begin(MI),
588 KE = LV->dead_end(MI); KI != KE; ++KI) {
589 unsigned VirtReg = KI->second;
590 unsigned PhysReg = VirtReg;
591 if (VirtReg >= MRegisterInfo::FirstVirtualRegister) {
592 std::map<unsigned, unsigned>::iterator I =
593 Virt2PhysRegMap.find(VirtReg);
594 assert(I != Virt2PhysRegMap.end());
596 Virt2PhysRegMap.erase(I);
600 DEBUG(std::cerr << " Register " << RegInfo->getName(PhysReg)
601 << " [%reg" << VirtReg
602 << "] is never used, removing it frame live list\n");
603 removePhysReg(PhysReg);
609 // Rewind the iterator to point to the first flow control instruction...
610 const TargetInstrInfo &TII = TM->getInstrInfo();
612 while (I != MBB.begin() && TII.isTerminatorInstr((*(I-1))->getOpcode()))
615 // Spill all physical registers holding virtual registers now.
616 while (!PhysRegsUsed.empty())
617 spillVirtReg(MBB, I, PhysRegsUsed.begin()->second,
618 PhysRegsUsed.begin()->first);
620 for (std::map<unsigned, unsigned>::iterator I = Virt2PhysRegMap.begin(),
621 E = Virt2PhysRegMap.end(); I != E; ++I)
622 std::cerr << "Register still mapped: " << I->first << " -> "
623 << I->second << "\n";
625 assert(Virt2PhysRegMap.empty() && "Virtual registers still in phys regs?");
626 assert(PhysRegsUseOrder.empty() && "Physical regs still allocated?");
630 /// runOnMachineFunction - Register allocate the whole function
632 bool RA::runOnMachineFunction(MachineFunction &Fn) {
633 DEBUG(std::cerr << "Machine Function " << "\n");
635 TM = &Fn.getTarget();
636 RegInfo = TM->getRegisterInfo();
639 LV = &getAnalysis<LiveVariables>();
641 // Loop over all of the basic blocks, eliminating virtual register references
642 for (MachineFunction::iterator MBB = Fn.begin(), MBBe = Fn.end();
644 AllocateBasicBlock(*MBB);
646 StackSlotForVirtReg.clear();
647 VirtRegModified.clear();
651 Pass *createLocalRegisterAllocator() {