Changes in directory llvm/lib/CodeGen:
VirtRegMap.cpp updated: 1.51 -> 1.52
---
Log message:
significantly simplify the VirtRegMap code by pulling the SpillSlotsAvailable
and PhysRegsAvailable maps out into a new AvailableSpills struct. No
functionality change.
This paves the way for a bugfix, coming up next.
---
Diffs of the changes: (+97 -69)
VirtRegMap.cpp | 166 +++++++++++++++++++++++++++++++++------------------------
1 files changed, 97 insertions(+), 69 deletions(-)
Index: llvm/lib/CodeGen/VirtRegMap.cpp
diff -u llvm/lib/CodeGen/VirtRegMap.cpp:1.51
llvm/lib/CodeGen/VirtRegMap.cpp:1.52
--- llvm/lib/CodeGen/VirtRegMap.cpp:1.51 Thu Feb 2 21:48:54 2006
+++ llvm/lib/CodeGen/VirtRegMap.cpp Fri Feb 3 17:13:58 2006
@@ -231,38 +231,92 @@
};
}
-void LocalSpiller::ClobberPhysRegOnly(unsigned PhysReg,
- std::map<int, unsigned> &SpillSlots,
- std::multimap<unsigned, int> &PhysRegsAvailable)
{
- std::multimap<unsigned, int>::iterator I =
PhysRegsAvailable.lower_bound(PhysReg);
+/// AvailableSpills - As the local spiller is scanning and rewriting an MBB
from
+/// top down, keep track of which spills slots are available in each register.
+class AvailableSpills {
+ const MRegisterInfo *MRI;
+ const TargetInstrInfo *TII;
+
+ // SpillSlotsAvailable - This map keeps track of all of the spilled virtual
+ // register values that are still available, due to being loaded or stored
to,
+ // but not invalidated yet.
+ std::map<int, unsigned> SpillSlotsAvailable;
+
+ // PhysRegsAvailable - This is the inverse of SpillSlotsAvailable, indicating
+ // 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;
+
+ void ClobberPhysRegOnly(unsigned PhysReg);
+public:
+ AvailableSpills(const MRegisterInfo *mri, const TargetInstrInfo *tii)
+ : MRI(mri), TII(tii) {
+ }
+
+ /// getSpillSlotPhysReg - If the specified stack slot is available in a
+ /// physical register, return that PhysReg, otherwise return 0.
+ unsigned getSpillSlotPhysReg(int Slot) const {
+ std::map<int, unsigned>::const_iterator I = SpillSlotsAvailable.find(Slot);
+ if (I != SpillSlotsAvailable.end())
+ return I->second;
+ return 0;
+ }
+
+ /// addAvailable - Mark that the specified stack slot is available in the
+ /// specified physreg.
+ void addAvailable(int Slot, unsigned Reg) {
+ PhysRegsAvailable.insert(std::make_pair(Reg, Slot));
+ SpillSlotsAvailable[Slot] = Reg;
+
+ DEBUG(std::cerr << "Remembering SS#" << Slot << " in physreg "
+ << MRI->getName(Reg) << "\n");
+ }
+
+
+ /// ClobberPhysReg - This is called when the specified physreg changes
+ /// value. We use this to invalidate any info about stuff we thing lives in
+ /// it and any of its aliases.
+ void ClobberPhysReg(unsigned PhysReg);
+
+ /// 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 ModifyStackSlot(int Slot);
+};
+
+/// ClobberPhysRegOnly - This is called when the specified physreg changes
+/// value. We use this to invalidate any info about stuff we thing lives in
it.
+void AvailableSpills::ClobberPhysRegOnly(unsigned PhysReg) {
+ std::multimap<unsigned, int>::iterator I =
+ PhysRegsAvailable.lower_bound(PhysReg);
while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
int Slot = I->second;
PhysRegsAvailable.erase(I++);
- assert(SpillSlots[Slot] == PhysReg && "Bidirectional map mismatch!");
- SpillSlots.erase(Slot);
+ assert(SpillSlotsAvailable[Slot] == PhysReg &&
+ "Bidirectional map mismatch!");
+ SpillSlotsAvailable.erase(Slot);
DEBUG(std::cerr << "PhysReg " << MRI->getName(PhysReg)
<< " clobbered, invalidating SS#" << Slot << "\n");
-
}
}
-void LocalSpiller::ClobberPhysReg(unsigned PhysReg,
- std::map<int, unsigned> &SpillSlots,
- std::multimap<unsigned, int> &PhysRegsAvailable)
{
+/// ClobberPhysReg - This is called when the specified physreg changes
+/// value. We use this to invalidate any info about stuff we thing lives in
+/// it and any of its aliases.
+void AvailableSpills::ClobberPhysReg(unsigned PhysReg) {
for (const unsigned *AS = MRI->getAliasSet(PhysReg); *AS; ++AS)
- ClobberPhysRegOnly(*AS, SpillSlots, PhysRegsAvailable);
- ClobberPhysRegOnly(PhysReg, SpillSlots, PhysRegsAvailable);
+ ClobberPhysRegOnly(*AS);
+ ClobberPhysRegOnly(PhysReg);
}
/// 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;
+void AvailableSpills::ModifyStackSlot(int Slot) {
+ std::map<int, unsigned>::iterator It = SpillSlotsAvailable.find(Slot);
+ if (It == SpillSlotsAvailable.end()) return;
unsigned Reg = It->second;
- SpillSlots.erase(It);
+ SpillSlotsAvailable.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.
@@ -308,18 +362,12 @@
/// register allocator is done with them. If possible, avoid reloading vregs.
void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, const VirtRegMap &VRM) {
- // SpillSlotsAvailable - This map keeps track of all of the spilled virtual
- // register values that are still available, due to being loaded or stored
to,
- // but not invalidated yet.
- std::map<int, unsigned> SpillSlotsAvailable;
-
- // PhysRegsAvailable - This is the inverse of SpillSlotsAvailable, indicating
- // 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");
+ // Spills - Keep track of which spilled values are available in physregs so
+ // that we can choose to reuse the physregs instead of emitting reloads.
+ AvailableSpills Spills(MRI, TII);
+
std::vector<ReusedOp> ReusedOperands;
// DefAndUseVReg - When we see a def&use operand that is spilled, keep track
@@ -387,15 +435,12 @@
unsigned PhysReg;
// Check to see if this stack slot is available.
- std::map<int, unsigned>::iterator SSI =
- SpillSlotsAvailable.find(StackSlot);
- if (SSI != SpillSlotsAvailable.end()) {
+ if ((PhysReg = Spills.getSpillSlotPhysReg(StackSlot))) {
+ // If this stack slot value is already available, reuse it!
DEBUG(std::cerr << "Reusing SS#" << StackSlot << " from physreg "
- << MRI->getName(SSI->second) << " for vreg"
+ << MRI->getName(PhysReg) << " for vreg"
<< VirtReg <<" instead of reloading into physreg "
<< MRI->getName(VRM.getPhys(VirtReg)) << "\n");
- // If this stack slot value is already available, reuse it!
- PhysReg = SSI->second;
MI.SetMachineOperandReg(i, PhysReg);
// The only technical detail we have is that we don't know that
@@ -446,20 +491,15 @@
MBB.getParent()->getSSARegMap()->getRegClass(Op.VirtReg);
MRI->loadRegFromStackSlot(MBB, &MI, Op.AssignedPhysReg,
Op.StackSlot, AliasRC);
- ClobberPhysReg(Op.AssignedPhysReg, SpillSlotsAvailable,
- PhysRegsAvailable);
-
+ Spills.ClobberPhysReg(Op.AssignedPhysReg);
+ Spills.ClobberPhysReg(Op.PhysRegReused);
+
// Any stores to this stack slot are not dead anymore.
MaybeDeadStores.erase(Op.StackSlot);
MI.SetMachineOperandReg(Op.Operand, Op.AssignedPhysReg);
- 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");
+
+ Spills.addAvailable(Op.StackSlot, Op.AssignedPhysReg);
++NumLoads;
DEBUG(std::cerr << '\t' << *prior(MII));
@@ -473,17 +513,13 @@
PhysRegsUsed[PhysReg] = true;
MRI->loadRegFromStackSlot(MBB, &MI, PhysReg, StackSlot, RC);
// This invalidates PhysReg.
- ClobberPhysReg(PhysReg, SpillSlotsAvailable, PhysRegsAvailable);
+ Spills.ClobberPhysReg(PhysReg);
// Any stores to this stack slot are not dead anymore.
MaybeDeadStores.erase(StackSlot);
-
- MI.SetMachineOperandReg(i, PhysReg);
- PhysRegsAvailable.insert(std::make_pair(PhysReg, StackSlot));
- SpillSlotsAvailable[StackSlot] = PhysReg;
- DEBUG(std::cerr << "Remembering SS#" << StackSlot <<" in physreg "
- << MRI->getName(PhysReg) << "\n");
+ Spills.addAvailable(StackSlot, PhysReg);
++NumLoads;
+ MI.SetMachineOperandReg(i, PhysReg);
DEBUG(std::cerr << '\t' << *prior(MII));
}
@@ -492,7 +528,7 @@
for (const unsigned *ImpDef = TII->getImplicitDefs(MI.getOpcode());
*ImpDef; ++ImpDef) {
PhysRegsUsed[*ImpDef] = true;
- ClobberPhysReg(*ImpDef, SpillSlotsAvailable, PhysRegsAvailable);
+ Spills.ClobberPhysReg(*ImpDef);
}
DEBUG(std::cerr << '\t' << MI);
@@ -520,12 +556,12 @@
if (unsigned DestReg = TII->isLoadFromStackSlot(&MI, FrameIdx)) {
// If this spill slot is available, turn it into a copy (or nothing)
// instead of leaving it as a load!
- std::map<int, unsigned>::iterator It = SpillSlotsAvailable.find(SS);
- if (FrameIdx == SS && It != SpillSlotsAvailable.end()) {
+ unsigned InReg;
+ if (FrameIdx == SS && (InReg = Spills.getSpillSlotPhysReg(SS))) {
DEBUG(std::cerr << "Promoted Load To Copy: " << MI);
MachineFunction &MF = *MBB.getParent();
- if (DestReg != It->second) {
- MRI->copyRegToReg(MBB, &MI, DestReg, It->second,
+ if (DestReg != InReg) {
+ MRI->copyRegToReg(MBB, &MI, DestReg, InReg,
MF.getSSARegMap()->getRegClass(VirtReg));
// Revisit the copy so we make sure to notice the effects of the
// operation on the destreg (either needing to RA it if it's
@@ -558,7 +594,7 @@
// the value, the value is not available anymore.
if (MR & VirtRegMap::isMod) {
// Notice that the value in this stack slot has been modified.
- ModifyStackSlot(SS, SpillSlotsAvailable, PhysRegsAvailable);
+ Spills.ModifyStackSlot(SS);
// 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
@@ -577,11 +613,7 @@
// 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.insert(std::make_pair(SrcReg, StackSlot));
- DEBUG(std::cerr << "Updating SS#" << StackSlot << " in physreg "
- << MRI->getName(SrcReg) << " for virtreg #"
- << VirtReg << "\n" << MI);
+ Spills.addAvailable(StackSlot, SrcReg);
}
}
}
@@ -616,7 +648,7 @@
MBB.erase(&MI);
goto ProcessNextInst;
}
- ClobberPhysReg(VirtReg, SpillSlotsAvailable, PhysRegsAvailable);
+ Spills.ClobberPhysReg(VirtReg);
continue;
}
}
@@ -664,14 +696,10 @@
// If the stack slot value was previously available in some other
// register, change it now. Otherwise, make the register available,
// in PhysReg.
- ModifyStackSlot(StackSlot, SpillSlotsAvailable, PhysRegsAvailable);
- ClobberPhysReg(PhysReg, SpillSlotsAvailable, PhysRegsAvailable);
+ Spills.ModifyStackSlot(StackSlot);
+ Spills.ClobberPhysReg(PhysReg);
- PhysRegsAvailable.insert(std::make_pair(PhysReg, StackSlot));
- SpillSlotsAvailable[StackSlot] = PhysReg;
- DEBUG(std::cerr << "Updating SS#" << StackSlot <<" in physreg "
- << MRI->getName(PhysReg) << " for virtreg #"
- << VirtReg << "\n");
+ Spills.addAvailable(StackSlot, PhysReg);
++NumStores;
}
}
_______________________________________________
llvm-commits mailing list
llvm-commits@cs.uiuc.edu
http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
