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-rw-r--r--lib/CodeGen/VirtRegMap.cpp86
1 files changed, 49 insertions, 37 deletions
diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index 77a028e5fc..608ff8bd8c 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -222,36 +222,60 @@ namespace {
private:
void RewriteMBB(MachineBasicBlock &MBB, const VirtRegMap &VRM);
void ClobberPhysReg(unsigned PR, std::map<int, unsigned> &SpillSlots,
- std::map<unsigned, int> &PhysRegs);
+ std::multimap<unsigned, int> &PhysRegs);
void ClobberPhysRegOnly(unsigned PR, std::map<int, unsigned> &SpillSlots,
- std::map<unsigned, int> &PhysRegs);
+ std::multimap<unsigned, int> &PhysRegs);
+ void ModifyStackSlot(int Slot, std::map<int, unsigned> &SpillSlots,
+ std::multimap<unsigned, int> &PhysRegs);
};
}
void LocalSpiller::ClobberPhysRegOnly(unsigned PhysReg,
std::map<int, unsigned> &SpillSlots,
- std::map<unsigned, int> &PhysRegs) {
- std::map<unsigned, int>::iterator I = PhysRegs.find(PhysReg);
- if (I != PhysRegs.end()) {
+ std::multimap<unsigned, int> &PhysRegsAvailable) {
+ std::map<unsigned, int>::iterator I = PhysRegsAvailable.lower_bound(PhysReg);
+ while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
int Slot = I->second;
- PhysRegs.erase(I);
+ PhysRegsAvailable.erase(I++);
assert(SpillSlots[Slot] == PhysReg && "Bidirectional map mismatch!");
SpillSlots.erase(Slot);
DEBUG(std::cerr << "PhysReg " << MRI->getName(PhysReg)
- << " clobbered, invalidating SS#" << Slot << "\n");
+ << " clobbered, invalidating SS#" << Slot << "\n");
}
}
void LocalSpiller::ClobberPhysReg(unsigned PhysReg,
std::map<int, unsigned> &SpillSlots,
- std::map<unsigned, int> &PhysRegs) {
+ std::multimap<unsigned, int> &PhysRegsAvailable) {
for (const unsigned *AS = MRI->getAliasSet(PhysReg); *AS; ++AS)
- ClobberPhysRegOnly(*AS, SpillSlots, PhysRegs);
- ClobberPhysRegOnly(PhysReg, SpillSlots, PhysRegs);
+ ClobberPhysRegOnly(*AS, SpillSlots, PhysRegsAvailable);
+ ClobberPhysRegOnly(PhysReg, SpillSlots, PhysRegsAvailable);
+}
+
+/// ModifyStackSlot - This method is called when the value in a stack slot
+/// changes. This removes information about which register the previous value
+/// for this slot lives in (as the previous value is dead now).
+void LocalSpiller::ModifyStackSlot(int Slot, std::map<int,unsigned> &SpillSlots,
+ std::multimap<unsigned, int> &PhysRegsAvailable) {
+ std::map<int, unsigned>::iterator It = SpillSlots.find(Slot);
+ if (It == SpillSlots.end()) return;
+ unsigned Reg = It->second;
+ SpillSlots.erase(It);
+
+ // This register may hold the value of multiple stack slots, only remove this
+ // stack slot from the set of values the register contains.
+ std::multimap<unsigned, int>::iterator I = PhysRegsAvailable.lower_bound(Reg);
+ for (; ; ++I) {
+ assert(I != PhysRegsAvailable.end() && I->first == Reg &&
+ "Map inverse broken!");
+ if (I->second == Slot) break;
+ }
+ PhysRegsAvailable.erase(I);
}
+
// ReusedOp - For each reused operand, we keep track of a bit of information, in
// case we need to rollback upon processing a new operand. See comments below.
namespace {
@@ -289,8 +313,9 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, const VirtRegMap &VRM) {
std::map<int, unsigned> SpillSlotsAvailable;
// PhysRegsAvailable - This is the inverse of SpillSlotsAvailable, indicating
- // which physregs are in use holding a stack slot value.
- std::map<unsigned, int> PhysRegsAvailable;
+ // which stack slot values are currently held by a physreg. This is used to
+ // invalidate entries in SpillSlotsAvailable when a physreg is modified.
+ std::multimap<unsigned, int> PhysRegsAvailable;
DEBUG(std::cerr << MBB.getBasicBlock()->getName() << ":\n");
@@ -427,12 +452,13 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, const VirtRegMap &VRM) {
MaybeDeadStores.erase(Op.StackSlot);
MI.SetMachineOperandReg(Op.Operand, Op.AssignedPhysReg);
- PhysRegsAvailable[Op.AssignedPhysReg] = Op.StackSlot;
+ PhysRegsAvailable.insert(std::make_pair(Op.AssignedPhysReg,
+ Op.StackSlot));
SpillSlotsAvailable[Op.StackSlot] = Op.AssignedPhysReg;
PhysRegsAvailable.erase(Op.PhysRegReused);
DEBUG(std::cerr << "Remembering SS#" << Op.StackSlot
- << " in physreg "
- << MRI->getName(Op.AssignedPhysReg) << "\n");
+ << " in physreg "
+ << MRI->getName(Op.AssignedPhysReg) << "\n");
++NumLoads;
DEBUG(std::cerr << '\t' << *prior(MII));
@@ -452,7 +478,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, const VirtRegMap &VRM) {
MaybeDeadStores.erase(StackSlot);
MI.SetMachineOperandReg(i, PhysReg);
- PhysRegsAvailable[PhysReg] = StackSlot;
+ PhysRegsAvailable.insert(std::make_pair(PhysReg, StackSlot));
SpillSlotsAvailable[StackSlot] = PhysReg;
DEBUG(std::cerr << "Remembering SS#" << StackSlot <<" in physreg "
<< MRI->getName(PhysReg) << "\n");
@@ -530,11 +556,8 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, const VirtRegMap &VRM) {
// If the spill slot value is available, and this is a new definition of
// the value, the value is not available anymore.
if (MR & VirtRegMap::isMod) {
- std::map<int, unsigned>::iterator It = SpillSlotsAvailable.find(SS);
- if (It != SpillSlotsAvailable.end()) {
- PhysRegsAvailable.erase(It->second);
- SpillSlotsAvailable.erase(It);
- }
+ // Notice that the value in this stack slot has been modified.
+ ModifyStackSlot(SS, SpillSlotsAvailable, PhysRegsAvailable);
// If this is *just* a mod of the value, check to see if this is just a
// store to the spill slot (i.e. the spill got merged into the copy). If
@@ -545,21 +568,16 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, const VirtRegMap &VRM) {
if (unsigned SrcReg = TII->isStoreToStackSlot(&MI, StackSlot)) {
assert(MRegisterInfo::isPhysicalRegister(SrcReg) &&
"Src hasn't been allocated yet?");
- // Okay, this is certainly a store of SrcReg to [FrameIdx]. Mark
+ // Okay, this is certainly a store of SrcReg to [StackSlot]. Mark
// this as a potentially dead store in case there is a subsequent
// store into the stack slot without a read from it.
MaybeDeadStores[StackSlot] = &MI;
- // FIXME: PhysRegsAvailable is a 1-1 map, not a N-1 map, which means
- // that we have to *forget* that SrcReg contains the old value it
- // does.
- ClobberPhysRegOnly(SrcReg, SpillSlotsAvailable, PhysRegsAvailable);
-
// If the stack slot value was previously available in some other
// register, change it now. Otherwise, make the register available,
// in PhysReg.
SpillSlotsAvailable[StackSlot] = SrcReg;
- PhysRegsAvailable[SrcReg] = StackSlot;
+ PhysRegsAvailable.insert(std::make_pair(SrcReg, StackSlot));
DEBUG(std::cerr << "Updating SS#" << StackSlot << " in physreg "
<< MRI->getName(SrcReg) << " for virtreg #"
<< VirtReg << "\n" << MI);
@@ -596,7 +614,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, const VirtRegMap &VRM) {
if (!TakenCareOf) {
// The only vregs left are stack slot definitions.
- int StackSlot = VRM.getStackSlot(VirtReg);
+ int StackSlot = VRM.getStackSlot(VirtReg);
const TargetRegisterClass *RC =
MBB.getParent()->getSSARegMap()->getRegClass(VirtReg);
unsigned PhysReg;
@@ -626,16 +644,10 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, const VirtRegMap &VRM) {
// If the stack slot value was previously available in some other
// register, change it now. Otherwise, make the register available,
// in PhysReg.
- std::map<int, unsigned>::iterator SSA =
- SpillSlotsAvailable.find(StackSlot);
- if (SSA != SpillSlotsAvailable.end()) {
- // Remove the record for physreg.
- PhysRegsAvailable.erase(SSA->second);
- SpillSlotsAvailable.erase(SSA);
- }
+ ModifyStackSlot(StackSlot, SpillSlotsAvailable, PhysRegsAvailable);
ClobberPhysReg(PhysReg, SpillSlotsAvailable, PhysRegsAvailable);
- PhysRegsAvailable[PhysReg] = StackSlot;
+ PhysRegsAvailable.insert(std::make_pair(PhysReg, StackSlot));
SpillSlotsAvailable[StackSlot] = PhysReg;
DEBUG(std::cerr << "Updating SS#" << StackSlot <<" in physreg "
<< MRI->getName(PhysReg) << " for virtreg #"
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-05-02 13:14:12 +0000