//===-- RegAllocLocal.cpp - A BasicBlock generic register allocator -------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
//
// This register allocator allocates registers to a basic block at a time,
// attempting to keep values in registers and reusing registers as appropriate.
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "regalloc"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "Support/Debug.h"
#include "Support/Statistic.h"
#include <iostream>
+using namespace llvm;
namespace {
Statistic<> NumSpilled ("ra-local", "Number of registers spilled");
Statistic<> NumReloaded("ra-local", "Number of registers reloaded");
- cl::opt<bool> DisableKill("no-kill", cl::Hidden,
+ cl::opt<bool> DisableKill("disable-kill", cl::Hidden,
cl::desc("Disable register kill in local-ra"));
class RA : public MachineFunctionPass {
const MRegisterInfo *RegInfo;
LiveVariables *LV;
- // StackSlotForVirtReg - Maps SSA Regs => frame index where these values are
- // spilled
+ // StackSlotForVirtReg - Maps virtual regs to the frame index where these
+ // values are spilled.
std::map<unsigned, int> StackSlotForVirtReg;
// Virt2PhysRegMap - This map contains entries for each virtual register
- // that is currently available in a physical register.
+ // that is currently available in a physical register. This is "logically"
+ // a map from virtual register numbers to physical register numbers.
+ // Instead of using a map, however, which is slow, we use a vector. The
+ // index is the VREG number - FirstVirtualRegister. If the entry is zero,
+ // then it is logically "not in the map".
//
- std::map<unsigned, unsigned> Virt2PhysRegMap;
+ std::vector<unsigned> Virt2PhysRegMap;
+
+ unsigned &getVirt2PhysRegMapSlot(unsigned VirtReg) {
+ assert(VirtReg >= MRegisterInfo::FirstVirtualRegister &&"Illegal VREG #");
+ assert(VirtReg-MRegisterInfo::FirstVirtualRegister <Virt2PhysRegMap.size()
+ && "VirtReg not in map!");
+ return Virt2PhysRegMap[VirtReg-MRegisterInfo::FirstVirtualRegister];
+ }
+ unsigned &getOrInsertVirt2PhysRegMapSlot(unsigned VirtReg) {
+ assert(VirtReg >= MRegisterInfo::FirstVirtualRegister &&"Illegal VREG #");
+ if (VirtReg-MRegisterInfo::FirstVirtualRegister >= Virt2PhysRegMap.size())
+ Virt2PhysRegMap.resize(VirtReg-MRegisterInfo::FirstVirtualRegister+1);
+ return Virt2PhysRegMap[VirtReg-MRegisterInfo::FirstVirtualRegister];
+ }
- // PhysRegsUsed - This map contains entries for each physical register that
- // currently has a value (ie, it is in Virt2PhysRegMap). The value mapped
- // to is the virtual register corresponding to the physical register (the
- // inverse of the Virt2PhysRegMap), or 0. The value is set to 0 if this
- // register is pinned because it is used by a future instruction.
+ // PhysRegsUsed - This array is effectively a map, containing entries for
+ // each physical register that currently has a value (ie, it is in
+ // Virt2PhysRegMap). The value mapped to is the virtual register
+ // corresponding to the physical register (the inverse of the
+ // Virt2PhysRegMap), or 0. The value is set to 0 if this register is pinned
+ // because it is used by a future instruction. If the entry for a physical
+ // register is -1, then the physical register is "not in the map".
//
- std::map<unsigned, unsigned> PhysRegsUsed;
+ int PhysRegsUsed[MRegisterInfo::FirstVirtualRegister];
// PhysRegsUseOrder - This contains a list of the physical registers that
// currently have a virtual register value in them. This list provides an
std::vector<bool> VirtRegModified;
void markVirtRegModified(unsigned Reg, bool Val = true) {
- assert(Reg >= MRegisterInfo::FirstVirtualRegister && "Illegal VirtReg!");
+ assert(MRegisterInfo::isVirtualRegister(Reg) && "Illegal VirtReg!");
Reg -= MRegisterInfo::FirstVirtualRegister;
if (VirtRegModified.size() <= Reg) VirtRegModified.resize(Reg+1);
VirtRegModified[Reg] = Val;
}
bool isVirtRegModified(unsigned Reg) const {
- assert(Reg >= MRegisterInfo::FirstVirtualRegister && "Illegal VirtReg!");
+ assert(MRegisterInfo::isVirtualRegister(Reg) && "Illegal VirtReg!");
assert(Reg - MRegisterInfo::FirstVirtualRegister < VirtRegModified.size()
&& "Illegal virtual register!");
return VirtRegModified[Reg - MRegisterInfo::FirstVirtualRegister];
if (!DisableKill)
AU.addRequired<LiveVariables>();
AU.addRequiredID(PHIEliminationID);
+ AU.addRequiredID(TwoAddressInstructionPassID);
MachineFunctionPass::getAnalysisUsage(AU);
}
///
bool areRegsEqual(unsigned R1, unsigned R2) const {
if (R1 == R2) return true;
- if (const unsigned *AliasSet = RegInfo->getAliasSet(R2))
- for (unsigned i = 0; AliasSet[i]; ++i)
- if (AliasSet[i] == R1) return true;
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(R2);
+ *AliasSet; ++AliasSet) {
+ if (*AliasSet == R1) return true;
+ }
return false;
}
/// getStackSpaceFor - This returns the frame index of the specified virtual
- /// register on the stack, allocating space if neccesary.
+ /// register on the stack, allocating space if necessary.
int getStackSpaceFor(unsigned VirtReg, const TargetRegisterClass *RC);
+ /// removePhysReg - This method marks the specified physical register as no
+ /// longer being in use.
+ ///
void removePhysReg(unsigned PhysReg);
/// spillVirtReg - This method spills the value specified by PhysReg into
unsigned VirtReg, unsigned PhysReg);
/// spillPhysReg - This method spills the specified physical register into
- /// the virtual register slot associated with it.
+ /// the virtual register slot associated with it. If OnlyVirtRegs is set to
+ /// true, then the request is ignored if the physical register does not
+ /// contain a virtual register.
///
void spillPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
- unsigned PhysReg);
+ unsigned PhysReg, bool OnlyVirtRegs = false);
/// assignVirtToPhysReg - This method updates local state so that we know
/// that PhysReg is the proper container for VirtReg now. The physical
///
unsigned reloadVirtReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &I, unsigned VirtReg);
+
+ void reloadPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
+ unsigned PhysReg);
};
}
-
-/// getStackSpaceFor - This allocates space for the specified virtual
-/// register to be held on the stack.
-int RA::getStackSpaceFor(unsigned VirtReg,
- const TargetRegisterClass *RC) {
- // Find the location VirtReg would belong...
- std::map<unsigned, int>::iterator I =
- StackSlotForVirtReg.lower_bound(VirtReg);
+/// getStackSpaceFor - This allocates space for the specified virtual register
+/// to be held on the stack.
+int RA::getStackSpaceFor(unsigned VirtReg, const TargetRegisterClass *RC) {
+ // Find the location Reg would belong...
+ std::map<unsigned, int>::iterator I =StackSlotForVirtReg.lower_bound(VirtReg);
if (I != StackSlotForVirtReg.end() && I->first == VirtReg)
return I->second; // Already has space allocated?
/// longer being in use.
///
void RA::removePhysReg(unsigned PhysReg) {
- PhysRegsUsed.erase(PhysReg); // PhyReg no longer used
+ PhysRegsUsed[PhysReg] = -1; // PhyReg no longer used
std::vector<unsigned>::iterator It =
std::find(PhysRegsUseOrder.begin(), PhysRegsUseOrder.end(), PhysReg);
- assert(It != PhysRegsUseOrder.end() &&
- "Spilled a physical register, but it was not in use list!");
- PhysRegsUseOrder.erase(It);
+ if (It != PhysRegsUseOrder.end())
+ PhysRegsUseOrder.erase(It);
}
///
void RA::spillVirtReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
unsigned VirtReg, unsigned PhysReg) {
- // If this is just a marker register, we don't need to spill it.
- if (VirtReg != 0) {
- const TargetRegisterClass *RegClass =
- MF->getSSARegMap()->getRegClass(VirtReg);
- int FrameIndex = getStackSpaceFor(VirtReg, RegClass);
-
- // If we need to spill this value, do so now...
- if (isVirtRegModified(VirtReg)) {
- // Add move instruction(s)
- RegInfo->storeRegToStackSlot(MBB, I, PhysReg, FrameIndex, RegClass);
- ++NumSpilled; // Update statistics
- }
- Virt2PhysRegMap.erase(VirtReg); // VirtReg no longer available
+ if (!VirtReg && DisableKill) return;
+ assert(VirtReg && "Spilling a physical register is illegal!"
+ " Must not have appropriate kill for the register or use exists beyond"
+ " the intended one.");
+ DEBUG(std::cerr << " Spilling register " << RegInfo->getName(PhysReg);
+ std::cerr << " containing %reg" << VirtReg;
+ if (!isVirtRegModified(VirtReg))
+ std::cerr << " which has not been modified, so no store necessary!");
+
+ // Otherwise, there is a virtual register corresponding to this physical
+ // register. We only need to spill it into its stack slot if it has been
+ // modified.
+ if (isVirtRegModified(VirtReg)) {
+ const TargetRegisterClass *RC = MF->getSSARegMap()->getRegClass(VirtReg);
+ int FrameIndex = getStackSpaceFor(VirtReg, RC);
+ DEBUG(std::cerr << " to stack slot #" << FrameIndex);
+ RegInfo->storeRegToStackSlot(MBB, I, PhysReg, FrameIndex, RC);
+ ++NumSpilled; // Update statistics
}
+ getVirt2PhysRegMapSlot(VirtReg) = 0; // VirtReg no longer available
+
+ DEBUG(std::cerr << "\n");
removePhysReg(PhysReg);
}
/// spillPhysReg - This method spills the specified physical register into the
-/// virtual register slot associated with it.
+/// virtual register slot associated with it. If OnlyVirtRegs is set to true,
+/// then the request is ignored if the physical register does not contain a
+/// virtual register.
///
void RA::spillPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
- unsigned PhysReg) {
- std::map<unsigned, unsigned>::iterator PI = PhysRegsUsed.find(PhysReg);
- if (PI != PhysRegsUsed.end()) { // Only spill it if it's used!
- spillVirtReg(MBB, I, PI->second, PhysReg);
- } else if (const unsigned *AliasSet = RegInfo->getAliasSet(PhysReg)) {
+ unsigned PhysReg, bool OnlyVirtRegs) {
+ if (PhysRegsUsed[PhysReg] != -1) { // Only spill it if it's used!
+ if (PhysRegsUsed[PhysReg] || !OnlyVirtRegs)
+ spillVirtReg(MBB, I, PhysRegsUsed[PhysReg], PhysReg);
+ } else {
// If the selected register aliases any other registers, we must make
// sure that one of the aliases isn't alive...
- for (unsigned i = 0; AliasSet[i]; ++i) {
- PI = PhysRegsUsed.find(AliasSet[i]);
- if (PI != PhysRegsUsed.end()) // Spill aliased register...
- spillVirtReg(MBB, I, PI->second, AliasSet[i]);
- }
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(PhysReg);
+ *AliasSet; ++AliasSet)
+ if (PhysRegsUsed[*AliasSet] != -1) // Spill aliased register...
+ if (PhysRegsUsed[*AliasSet] || !OnlyVirtRegs)
+ spillVirtReg(MBB, I, PhysRegsUsed[*AliasSet], *AliasSet);
}
}
/// register must not be used for anything else when this is called.
///
void RA::assignVirtToPhysReg(unsigned VirtReg, unsigned PhysReg) {
- assert(PhysRegsUsed.find(PhysReg) == PhysRegsUsed.end() &&
- "Phys reg already assigned!");
+ assert(PhysRegsUsed[PhysReg] == -1 && "Phys reg already assigned!");
// Update information to note the fact that this register was just used, and
// it holds VirtReg.
PhysRegsUsed[PhysReg] = VirtReg;
- Virt2PhysRegMap[VirtReg] = PhysReg;
+ getOrInsertVirt2PhysRegMapSlot(VirtReg) = PhysReg;
PhysRegsUseOrder.push_back(PhysReg); // New use of PhysReg
}
/// registers are all free...
///
bool RA::isPhysRegAvailable(unsigned PhysReg) const {
- if (PhysRegsUsed.count(PhysReg)) return false;
+ if (PhysRegsUsed[PhysReg] != -1) return false;
// If the selected register aliases any other allocated registers, it is
// not free!
- if (const unsigned *AliasSet = RegInfo->getAliasSet(PhysReg))
- for (unsigned i = 0; AliasSet[i]; ++i)
- if (PhysRegsUsed.count(AliasSet[i])) // Aliased register in use?
- return false; // Can't use this reg then.
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(PhysReg);
+ *AliasSet; ++AliasSet)
+ if (PhysRegsUsed[*AliasSet] != -1) // Aliased register in use?
+ return false; // Can't use this reg then.
return true;
}
// Check to see if the register is directly used, not indirectly used through
// aliases. If aliased registers are the ones actually used, we cannot be
// sure that we will be able to save the whole thing if we do a reg-reg copy.
- std::map<unsigned, unsigned>::iterator PRUI = PhysRegsUsed.find(PhysReg);
- if (PRUI != PhysRegsUsed.end()) {
- unsigned VirtReg = PRUI->second; // The virtual register held...
+ if (PhysRegsUsed[PhysReg] != -1) {
+ // The virtual register held...
+ unsigned VirtReg = PhysRegsUsed[PhysReg]->second;
// Check to see if there is a compatible register available. If so, we can
// move the value into the new register...
// Update our internal state to indicate that PhysReg is available and Reg
// isn't.
- Virt2PhysRegMap.erase(VirtReg);
+ getVirt2PhysRegMapSlot[VirtReg] = 0;
removePhysReg(PhysReg); // Free the physreg
// Move reference over to new register...
"Couldn't find a register of the appropriate class!");
unsigned R = PhysRegsUseOrder[i];
- // If the current register is compatible, use it.
- if (RegInfo->getRegClass(R) == RC) {
- PhysReg = R;
- break;
- } else {
- // If one of the registers aliased to the current register is
- // compatible, use it.
- if (const unsigned *AliasSet = RegInfo->getAliasSet(R))
- for (unsigned a = 0; AliasSet[a]; ++a)
- if (RegInfo->getRegClass(AliasSet[a]) == RC) {
- PhysReg = AliasSet[a]; // Take an aliased register
- break;
- }
+
+ // We can only use this register if it holds a virtual register (ie, it
+ // can be spilled). Do not use it if it is an explicitly allocated
+ // physical register!
+ assert(PhysRegsUsed[R] != -1 &&
+ "PhysReg in PhysRegsUseOrder, but is not allocated?");
+ if (PhysRegsUsed[R]) {
+ // If the current register is compatible, use it.
+ if (RegInfo->getRegClass(R) == RC) {
+ PhysReg = R;
+ break;
+ } else {
+ // If one of the registers aliased to the current register is
+ // compatible, use it.
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(R);
+ *AliasSet; ++AliasSet) {
+ if (RegInfo->getRegClass(*AliasSet) == RC) {
+ PhysReg = *AliasSet; // Take an aliased register
+ break;
+ }
+ }
+ }
}
}
unsigned RA::reloadVirtReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &I,
unsigned VirtReg) {
- std::map<unsigned, unsigned>::iterator It = Virt2PhysRegMap.find(VirtReg);
- if (It != Virt2PhysRegMap.end()) {
- MarkPhysRegRecentlyUsed(It->second);
- return It->second; // Already have this value available!
+ if (unsigned PR = getOrInsertVirt2PhysRegMapSlot(VirtReg)) {
+ MarkPhysRegRecentlyUsed(PR);
+ return PR; // Already have this value available!
}
unsigned PhysReg = getReg(MBB, I, VirtReg);
markVirtRegModified(VirtReg, false); // Note that this reg was just reloaded
+ DEBUG(std::cerr << " Reloading %reg" << VirtReg << " into "
+ << RegInfo->getName(PhysReg) << "\n");
+
// Add move instruction(s)
RegInfo->loadRegFromStackSlot(MBB, I, PhysReg, FrameIndex, RC);
++NumReloaded; // Update statistics
return PhysReg;
}
+
+
void RA::AllocateBasicBlock(MachineBasicBlock &MBB) {
// loop over each instruction
MachineBasicBlock::iterator I = MBB.begin();
for (; I != MBB.end(); ++I) {
MachineInstr *MI = *I;
const TargetInstrDescriptor &TID = TM->getInstrInfo().get(MI->getOpcode());
+ DEBUG(std::cerr << "\nStarting RegAlloc of: " << *MI;
+ std::cerr << " Regs have values: ";
+ for (unsigned i = 0; i != RegInfo->getNumRegs(); ++i)
+ if (PhysRegsUsed[i] != -1)
+ std::cerr << "[" << RegInfo->getName(i)
+ << ",%reg" << PhysRegsUsed[i] << "] ";
+ std::cerr << "\n");
// Loop over the implicit uses, making sure that they are at the head of the
// use order list, so they don't get reallocated.
- if (const unsigned *ImplicitUses = TID.ImplicitUses)
- for (unsigned i = 0; ImplicitUses[i]; ++i)
- MarkPhysRegRecentlyUsed(ImplicitUses[i]);
-
- // Get the used operands into registers. This has the potiential to spill
- // incoming values if we are out of registers.
+ for (const unsigned *ImplicitUses = TID.ImplicitUses;
+ *ImplicitUses; ++ImplicitUses)
+ MarkPhysRegRecentlyUsed(*ImplicitUses);
+
+ // Get the used operands into registers. This has the potential to spill
+ // incoming values if we are out of registers. Note that we completely
+ // ignore physical register uses here. We assume that if an explicit
+ // physical register is referenced by the instruction, that it is guaranteed
+ // to be live-in, or the input is badly hosed.
//
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
- if (MI->getOperand(i).opIsUse() &&
- MI->getOperand(i).isVirtualRegister()) {
+ if (MI->getOperand(i).isUse() &&
+ !MI->getOperand(i).isDef() &&
+ MI->getOperand(i).isVirtualRegister()){
unsigned VirtSrcReg = MI->getOperand(i).getAllocatedRegNum();
unsigned PhysSrcReg = reloadVirtReg(MBB, I, VirtSrcReg);
MI->SetMachineOperandReg(i, PhysSrcReg); // Assign the input register
KE = LV->killed_end(MI); KI != KE; ++KI) {
unsigned VirtReg = KI->second;
unsigned PhysReg = VirtReg;
- if (VirtReg >= MRegisterInfo::FirstVirtualRegister) {
- std::map<unsigned, unsigned>::iterator I =
- Virt2PhysRegMap.find(VirtReg);
- assert(I != Virt2PhysRegMap.end());
- PhysReg = I->second;
- Virt2PhysRegMap.erase(I);
+ if (MRegisterInfo::isVirtualRegister(VirtReg)) {
+ unsigned &PhysRegSlot = getVirt2PhysRegMapSlot(VirtReg);
+ PhysReg = PhysRegSlot;
+ assert(PhysReg != 0);
+ PhysRegSlot = 0;
}
if (PhysReg) {
- DEBUG(std::cerr << "V: " << VirtReg << " P: " << PhysReg
- << " Killed by: " << *MI);
+ DEBUG(std::cerr << " Last use of " << RegInfo->getName(PhysReg)
+ << "[%reg" << VirtReg <<"], removing it from live set\n");
removePhysReg(PhysReg);
}
}
// Loop over all of the operands of the instruction, spilling registers that
// are defined, and marking explicit destinations in the PhysRegsUsed map.
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
- if ((MI->getOperand(i).opIsDefOnly() ||
- MI->getOperand(i).opIsDefAndUse()) &&
- MI->getOperand(i).isPhysicalRegister()) {
+ if (MI->getOperand(i).isDef() && MI->getOperand(i).isRegister() &&
+ MRegisterInfo::isPhysicalRegister(MI->getOperand(i).getReg())) {
unsigned Reg = MI->getOperand(i).getAllocatedRegNum();
- spillPhysReg(MBB, I, Reg); // Spill any existing value in the reg
+ spillPhysReg(MBB, I, Reg, true); // Spill any existing value in the reg
PhysRegsUsed[Reg] = 0; // It is free and reserved now
PhysRegsUseOrder.push_back(Reg);
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
+ *AliasSet; ++AliasSet) {
+ PhysRegsUseOrder.push_back(*AliasSet);
+ PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
+ }
}
// Loop over the implicit defs, spilling them as well.
- if (const unsigned *ImplicitDefs = TID.ImplicitDefs)
- for (unsigned i = 0; ImplicitDefs[i]; ++i) {
- unsigned Reg = ImplicitDefs[i];
- spillPhysReg(MBB, I, Reg);
- PhysRegsUseOrder.push_back(Reg);
- PhysRegsUsed[Reg] = 0; // It is free and reserved now
+ for (const unsigned *ImplicitDefs = TID.ImplicitDefs;
+ *ImplicitDefs; ++ImplicitDefs) {
+ unsigned Reg = *ImplicitDefs;
+ spillPhysReg(MBB, I, Reg);
+ PhysRegsUseOrder.push_back(Reg);
+ PhysRegsUsed[Reg] = 0; // It is free and reserved now
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
+ *AliasSet; ++AliasSet) {
+ PhysRegsUseOrder.push_back(*AliasSet);
+ PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
}
+ }
// Okay, we have allocated all of the source operands and spilled any values
// that would be destroyed by defs of this instruction. Loop over the
// we need to scavenge a register.
//
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
- if ((MI->getOperand(i).opIsDefOnly() || MI->getOperand(i).opIsDefAndUse())
- && MI->getOperand(i).isVirtualRegister()) {
+ if (MI->getOperand(i).isDef() &&
+ MI->getOperand(i).isVirtualRegister()) {
unsigned DestVirtReg = MI->getOperand(i).getAllocatedRegNum();
unsigned DestPhysReg;
- // If DestVirtReg already has a value, forget about it. Why doesn't
- // getReg do this right?
- std::map<unsigned, unsigned>::iterator DestI =
- Virt2PhysRegMap.find(DestVirtReg);
- if (DestI != Virt2PhysRegMap.end()) {
- unsigned PhysReg = DestI->second;
- Virt2PhysRegMap.erase(DestI);
- removePhysReg(PhysReg);
- }
-
- if (TM->getInstrInfo().isTwoAddrInstr(MI->getOpcode()) && i == 0) {
- // must be same register number as the first operand
- // This maps a = b + c into b += c, and saves b into a's spot
- assert(MI->getOperand(1).isRegister() &&
- MI->getOperand(1).getAllocatedRegNum() &&
- MI->getOperand(1).opIsUse() &&
- "Two address instruction invalid!");
- DestPhysReg = MI->getOperand(1).getAllocatedRegNum();
-
- liberatePhysReg(MBB, I, DestPhysReg);
- assignVirtToPhysReg(DestVirtReg, DestPhysReg);
- } else {
+ // If DestVirtReg already has a value, use it.
+ if (!(DestPhysReg = getOrInsertVirt2PhysRegMapSlot(DestVirtReg)))
DestPhysReg = getReg(MBB, I, DestVirtReg);
- }
markVirtRegModified(DestVirtReg);
MI->SetMachineOperandReg(i, DestPhysReg); // Assign the output register
}
KE = LV->dead_end(MI); KI != KE; ++KI) {
unsigned VirtReg = KI->second;
unsigned PhysReg = VirtReg;
- if (VirtReg >= MRegisterInfo::FirstVirtualRegister) {
- std::map<unsigned, unsigned>::iterator I =
- Virt2PhysRegMap.find(VirtReg);
- assert(I != Virt2PhysRegMap.end());
- PhysReg = I->second;
- Virt2PhysRegMap.erase(I);
+ if (MRegisterInfo::isVirtualRegister(VirtReg)) {
+ unsigned &PhysRegSlot = getVirt2PhysRegMapSlot(VirtReg);
+ PhysReg = PhysRegSlot;
+ assert(PhysReg != 0);
+ PhysRegSlot = 0;
}
if (PhysReg) {
- DEBUG(std::cerr << "V: " << VirtReg << " P: " << PhysReg
- << " dead after: " << *MI);
+ DEBUG(std::cerr << " Register " << RegInfo->getName(PhysReg)
+ << " [%reg" << VirtReg
+ << "] is never used, removing it frame live list\n");
removePhysReg(PhysReg);
}
}
--I;
// Spill all physical registers holding virtual registers now.
- while (!PhysRegsUsed.empty())
- spillVirtReg(MBB, I, PhysRegsUsed.begin()->second,
- PhysRegsUsed.begin()->first);
-
- for (std::map<unsigned, unsigned>::iterator I = Virt2PhysRegMap.begin(),
- E = Virt2PhysRegMap.end(); I != E; ++I)
- std::cerr << "Register still mapped: " << I->first << " -> "
- << I->second << "\n";
-
- assert(Virt2PhysRegMap.empty() && "Virtual registers still in phys regs?");
- assert(PhysRegsUseOrder.empty() && "Physical regs still allocated?");
+ for (unsigned i = 0, e = RegInfo->getNumRegs(); i != e; ++i)
+ if (PhysRegsUsed[i] != -1)
+ if (unsigned VirtReg = PhysRegsUsed[i])
+ spillVirtReg(MBB, I, VirtReg, i);
+ else
+ removePhysReg(i);
+
+#ifndef NDEBUG
+ bool AllOk = true;
+ for (unsigned i = 0, e = Virt2PhysRegMap.size(); i != e; ++i)
+ if (unsigned PR = Virt2PhysRegMap[i]) {
+ std::cerr << "Register still mapped: " << i << " -> " << PR << "\n";
+ AllOk = false;
+ }
+ assert(AllOk && "Virtual registers still in phys regs?");
+#endif
+
+ // Clear any physical register which appear live at the end of the basic
+ // block, but which do not hold any virtual registers. e.g., the stack
+ // pointer.
+ PhysRegsUseOrder.clear();
}
TM = &Fn.getTarget();
RegInfo = TM->getRegisterInfo();
+ memset(PhysRegsUsed, -1, RegInfo->getNumRegs()*sizeof(unsigned));
+
+ // Reserve some space for a moderate number of registers. If we know what the
+ // max virtual register number was we could use that instead and save some
+ // runtime overhead...
+ Virt2PhysRegMap.resize(1024);
+
if (!DisableKill)
LV = &getAnalysis<LiveVariables>();
StackSlotForVirtReg.clear();
VirtRegModified.clear();
+ Virt2PhysRegMap.clear();
return true;
}
-Pass *createLocalRegisterAllocator() {
+FunctionPass *llvm::createLocalRegisterAllocator() {
return new RA();
}
+
projects / oota-llvm.git / blobdiff