[llvm-commits] CVS: llvm/lib/CodeGen/VirtRegMap.cpp
Evan Cheng
evan.cheng at apple.com
Thu Feb 22 17:13:42 PST 2007
Changes in directory llvm/lib/CodeGen:
VirtRegMap.cpp updated: 1.97 -> 1.98
---
Log message:
A spill kills the register being stored. But it is later being reused by spiller, its live range has to be extended.
---
Diffs of the changes: (+39 -25)
VirtRegMap.cpp | 64 ++++++++++++++++++++++++++++++++++-----------------------
1 files changed, 39 insertions(+), 25 deletions(-)
Index: llvm/lib/CodeGen/VirtRegMap.cpp
diff -u llvm/lib/CodeGen/VirtRegMap.cpp:1.97 llvm/lib/CodeGen/VirtRegMap.cpp:1.98
--- llvm/lib/CodeGen/VirtRegMap.cpp:1.97 Tue Feb 20 20:22:03 2007
+++ llvm/lib/CodeGen/VirtRegMap.cpp Thu Feb 22 19:13:26 2007
@@ -255,7 +255,8 @@
// 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;
+ typedef std::pair<unsigned, MachineInstr*> SSInfo;
+ std::map<int, SSInfo> SpillSlotsAvailable;
// PhysRegsAvailable - This is the inverse of SpillSlotsAvailable, indicating
// which stack slot values are currently held by a physreg. This is used to
@@ -270,27 +271,33 @@
: MRI(mri), TII(tii) {
}
+ const MRegisterInfo *getRegInfo() const { return MRI; }
+
/// 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 >> 1; // Remove the CanClobber bit.
+ /// physical register, return that PhysReg, otherwise return 0. It also
+ /// returns by reference the instruction that either defines or last uses
+ /// the register.
+ unsigned getSpillSlotPhysReg(int Slot, MachineInstr *&SSMI) const {
+ std::map<int, SSInfo>::const_iterator I = SpillSlotsAvailable.find(Slot);
+ if (I != SpillSlotsAvailable.end()) {
+ SSMI = I->second.second;
+ return I->second.first >> 1; // Remove the CanClobber bit.
+ }
return 0;
}
- const MRegisterInfo *getRegInfo() const { return MRI; }
-
/// addAvailable - Mark that the specified stack slot is available in the
/// specified physreg. If CanClobber is true, the physreg can be modified at
/// any time without changing the semantics of the program.
- void addAvailable(int Slot, unsigned Reg, bool CanClobber = true) {
+ void addAvailable(int Slot, MachineInstr *MI, unsigned Reg,
+ bool CanClobber = true) {
// If this stack slot is thought to be available in some other physreg,
// remove its record.
ModifyStackSlot(Slot);
PhysRegsAvailable.insert(std::make_pair(Reg, Slot));
- SpillSlotsAvailable[Slot] = (Reg << 1) | (unsigned)CanClobber;
+ SpillSlotsAvailable[Slot] =
+ std::make_pair((Reg << 1) | (unsigned)CanClobber, MI);
DOUT << "Remembering SS#" << Slot << " in physreg "
<< MRI->getName(Reg) << "\n";
@@ -301,7 +308,7 @@
/// stack slot must be available in a physreg for this query to make sense.
bool canClobberPhysReg(int Slot) const {
assert(SpillSlotsAvailable.count(Slot) && "Slot not available!");
- return SpillSlotsAvailable.find(Slot)->second & 1;
+ return SpillSlotsAvailable.find(Slot)->second.first & 1;
}
/// disallowClobberPhysReg - Unset the CanClobber bit of the specified
@@ -330,9 +337,9 @@
while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
int Slot = I->second;
I++;
- assert((SpillSlotsAvailable[Slot] >> 1) == PhysReg &&
+ assert((SpillSlotsAvailable[Slot].first >> 1) == PhysReg &&
"Bidirectional map mismatch!");
- SpillSlotsAvailable[Slot] &= ~1;
+ SpillSlotsAvailable[Slot].first &= ~1;
DOUT << "PhysReg " << MRI->getName(PhysReg)
<< " copied, it is available for use but can no longer be modified\n";
}
@@ -355,7 +362,7 @@
while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
int Slot = I->second;
PhysRegsAvailable.erase(I++);
- assert((SpillSlotsAvailable[Slot] >> 1) == PhysReg &&
+ assert((SpillSlotsAvailable[Slot].first >> 1) == PhysReg &&
"Bidirectional map mismatch!");
SpillSlotsAvailable.erase(Slot);
DOUT << "PhysReg " << MRI->getName(PhysReg)
@@ -376,9 +383,9 @@
/// changes. This removes information about which register the previous value
/// for this slot lives in (as the previous value is dead now).
void AvailableSpills::ModifyStackSlot(int Slot) {
- std::map<int, unsigned>::iterator It = SpillSlotsAvailable.find(Slot);
+ std::map<int, SSInfo>::iterator It = SpillSlotsAvailable.find(Slot);
if (It == SpillSlotsAvailable.end()) return;
- unsigned Reg = It->second >> 1;
+ unsigned Reg = It->second.first >> 1;
SpillSlotsAvailable.erase(It);
// This register may hold the value of multiple stack slots, only remove this
@@ -514,7 +521,7 @@
MI->getOperand(NewOp.Operand).setReg(NewPhysReg);
- Spills.addAvailable(NewOp.StackSlot, NewPhysReg);
+ Spills.addAvailable(NewOp.StackSlot, MI, NewPhysReg);
++NumLoads;
DEBUG(MachineBasicBlock::iterator MII = MI;
DOUT << '\t' << *prior(MII));
@@ -628,8 +635,8 @@
unsigned PhysReg;
// Check to see if this stack slot is available.
- if ((PhysReg = Spills.getSpillSlotPhysReg(StackSlot))) {
-
+ MachineInstr *SSMI = NULL;
+ if ((PhysReg = Spills.getSpillSlotPhysReg(StackSlot, SSMI))) {
// This spilled operand might be part of a two-address operand. If this
// is the case, then changing it will necessarily require changing the
// def part of the instruction as well. However, in some cases, we
@@ -655,6 +662,12 @@
<< MRI->getName(VRM.getPhys(VirtReg)) << "\n";
MI.getOperand(i).setReg(PhysReg);
+ // Extend the live range of the MI that last kill the register if
+ // necessary.
+ MachineOperand *MOK = SSMI->findRegisterUseOperand(PhysReg, true);
+ if (MOK)
+ MOK->unsetIsKill();
+
// The only technical detail we have is that we don't know that
// PhysReg won't be clobbered by a reloaded stack slot that occurs
// later in the instruction. In particular, consider 'op V1, V2'.
@@ -723,7 +736,7 @@
// This invalidates DesignatedReg.
Spills.ClobberPhysReg(DesignatedReg);
- Spills.addAvailable(StackSlot, DesignatedReg);
+ Spills.addAvailable(StackSlot, &MI, DesignatedReg);
MI.getOperand(i).setReg(DesignatedReg);
DOUT << '\t' << *prior(MII);
++NumReused;
@@ -752,7 +765,7 @@
// Any stores to this stack slot are not dead anymore.
MaybeDeadStores.erase(StackSlot);
- Spills.addAvailable(StackSlot, PhysReg);
+ Spills.addAvailable(StackSlot, &MI, PhysReg);
++NumLoads;
MI.getOperand(i).setReg(PhysReg);
DOUT << '\t' << *prior(MII);
@@ -784,7 +797,8 @@
if (FrameIdx == SS) {
// If this spill slot is available, turn it into a copy (or nothing)
// instead of leaving it as a load!
- if (unsigned InReg = Spills.getSpillSlotPhysReg(SS)) {
+ MachineInstr *Dummy = NULL;
+ if (unsigned InReg = Spills.getSpillSlotPhysReg(SS, Dummy)) {
DOUT << "Promoted Load To Copy: " << MI;
MachineFunction &MF = *MBB.getParent();
if (DestReg != InReg) {
@@ -844,7 +858,7 @@
// If the stack slot value was previously available in some other
// register, change it now. Otherwise, make the register available,
// in PhysReg.
- Spills.addAvailable(StackSlot, SrcReg, false /*don't clobber*/);
+ Spills.addAvailable(StackSlot, &MI, SrcReg, false/*don't clobber*/);
}
}
}
@@ -880,7 +894,7 @@
assert(DestReg == VirtReg && "Unknown load situation!");
// Otherwise, if it wasn't available, remember that it is now!
- Spills.addAvailable(FrameIdx, DestReg);
+ Spills.addAvailable(FrameIdx, &MI, DestReg);
goto ProcessNextInst;
}
@@ -929,7 +943,7 @@
// in PhysReg.
Spills.ModifyStackSlot(StackSlot);
Spills.ClobberPhysReg(PhysReg);
- Spills.addAvailable(StackSlot, PhysReg);
+ Spills.addAvailable(StackSlot, LastStore, PhysReg);
++NumStores;
// Check to see if this is a noop copy. If so, eliminate the
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