[llvm-commits] [llvm] r158256 - in /llvm/trunk: include/llvm/CodeGen/RegisterPressure.h lib/CodeGen/RegisterPressure.cpp
Andrew Trick
atrick at apple.com
Fri Jun 8 19:16:59 PDT 2012
Author: atrick
Date: Fri Jun 8 21:16:58 2012
New Revision: 158256
URL: http://llvm.org/viewvc/llvm-project?rev=158256&view=rev
Log:
Register pressure: added getPressureAfterInstr.
Modified:
llvm/trunk/include/llvm/CodeGen/RegisterPressure.h
llvm/trunk/lib/CodeGen/RegisterPressure.cpp
Modified: llvm/trunk/include/llvm/CodeGen/RegisterPressure.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/RegisterPressure.h?rev=158256&r1=158255&r2=158256&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/RegisterPressure.h (original)
+++ llvm/trunk/include/llvm/CodeGen/RegisterPressure.h Fri Jun 8 21:16:58 2012
@@ -198,6 +198,10 @@
/// or if closeRegion() was explicitly invoked.
RegisterPressure &getPressure() { return P; }
+ /// Get the register set pressure at the current position, which may be less
+ /// than the pressure across the traversed region.
+ std::vector<unsigned> &getRegSetPressureAtPos() { return CurrSetPressure; }
+
void discoverPhysLiveIn(unsigned Reg);
void discoverPhysLiveOut(unsigned Reg);
@@ -243,12 +247,32 @@
MaxPressureLimit);
}
+ /// Get the pressure of each PSet after traversing this instruction bottom-up.
+ void getUpwardPressure(const MachineInstr *MI,
+ std::vector<unsigned> &PressureResult);
+
+ /// Get the pressure of each PSet after traversing this instruction top-down.
+ void getDownwardPressure(const MachineInstr *MI,
+ std::vector<unsigned> &PressureResult);
+
+ void getPressureAfterInst(const MachineInstr *MI,
+ std::vector<unsigned> &PressureResult) {
+ if (isTopClosed())
+ return getUpwardPressure(MI, PressureResult);
+
+ assert(isBottomClosed() && "Uninitialized pressure tracker");
+ return getDownwardPressure(MI, PressureResult);
+ }
+
protected:
void increasePhysRegPressure(ArrayRef<unsigned> Regs);
void decreasePhysRegPressure(ArrayRef<unsigned> Regs);
void increaseVirtRegPressure(ArrayRef<unsigned> Regs);
void decreaseVirtRegPressure(ArrayRef<unsigned> Regs);
+
+ void bumpUpwardPressure(const MachineInstr *MI);
+ void bumpDownwardPressure(const MachineInstr *MI);
};
} // end namespace llvm
Modified: llvm/trunk/lib/CodeGen/RegisterPressure.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegisterPressure.cpp?rev=158256&r1=158255&r2=158256&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegisterPressure.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegisterPressure.cpp Fri Jun 8 21:16:58 2012
@@ -654,32 +654,18 @@
}
}
-/// Consider the pressure increase caused by traversing this instruction
-/// bottom-up. Find the pressure set with the most change beyond its pressure
-/// limit based on the tracker's current pressure, and return the change in
-/// number of register units of that pressure set introduced by this
-/// instruction.
+/// Record the upward impact of a single instruction on current register
+/// pressure. Unlike the advance/recede pressure tracking interface, this does
+/// not discover live in/outs.
///
-/// This assumes that the current LiveOut set is sufficient.
-///
-/// FIXME: This is expensive for an on-the-fly query. We need to cache the
-/// result per-SUnit with enough information to adjust for the current
-/// scheduling position. But this works as a proof of concept.
-void RegPressureTracker::
-getMaxUpwardPressureDelta(const MachineInstr *MI, RegPressureDelta &Delta,
- ArrayRef<PressureElement> CriticalPSets,
- ArrayRef<unsigned> MaxPressureLimit) {
+/// This is intended for speculative queries. It leaves pressure inconsistent
+/// with the current position, so must be restored by the caller.
+void RegPressureTracker::bumpUpwardPressure(const MachineInstr *MI) {
// Account for register pressure similar to RegPressureTracker::recede().
PhysRegOperands PhysRegOpers;
VirtRegOperands VirtRegOpers;
collectOperands(MI, PhysRegOpers, VirtRegOpers, TRI, RCI);
- // Snapshot Pressure.
- // FIXME: The snapshot heap space should persist. But I'm planning to
- // summarize the pressure effect so we don't need to snapshot at all.
- std::vector<unsigned> SavedPressure = CurrSetPressure;
- std::vector<unsigned> SavedMaxPressure = P.MaxSetPressure;
-
// Boost max pressure for all dead defs together.
// Since CurrSetPressure and MaxSetPressure
increasePhysRegPressure(PhysRegOpers.DeadDefs);
@@ -708,6 +694,31 @@
increaseVirtRegPressure(Reg);
}
}
+}
+
+/// Consider the pressure increase caused by traversing this instruction
+/// bottom-up. Find the pressure set with the most change beyond its pressure
+/// limit based on the tracker's current pressure, and return the change in
+/// number of register units of that pressure set introduced by this
+/// instruction.
+///
+/// This assumes that the current LiveOut set is sufficient.
+///
+/// FIXME: This is expensive for an on-the-fly query. We need to cache the
+/// result per-SUnit with enough information to adjust for the current
+/// scheduling position. But this works as a proof of concept.
+void RegPressureTracker::
+getMaxUpwardPressureDelta(const MachineInstr *MI, RegPressureDelta &Delta,
+ ArrayRef<PressureElement> CriticalPSets,
+ ArrayRef<unsigned> MaxPressureLimit) {
+ // Snapshot Pressure.
+ // FIXME: The snapshot heap space should persist. But I'm planning to
+ // summarize the pressure effect so we don't need to snapshot at all.
+ std::vector<unsigned> SavedPressure = CurrSetPressure;
+ std::vector<unsigned> SavedMaxPressure = P.MaxSetPressure;
+
+ bumpUpwardPressure(MI);
+
computeExcessPressureDelta(SavedPressure, CurrSetPressure, Delta, TRI);
computeMaxPressureDelta(SavedMaxPressure, P.MaxSetPressure, CriticalPSets,
MaxPressureLimit, Delta);
@@ -735,25 +746,18 @@
return false;
}
-/// Consider the pressure increase caused by traversing this instruction
-/// top-down. Find the register class with the most change in its pressure limit
-/// based on the tracker's current pressure, and return the number of excess
-/// register units of that pressure set introduced by this instruction.
+/// Record the downward impact of a single instruction on current register
+/// pressure. Unlike the advance/recede pressure tracking interface, this does
+/// not discover live in/outs.
///
-/// This assumes that the current LiveIn set is sufficient.
-void RegPressureTracker::
-getMaxDownwardPressureDelta(const MachineInstr *MI, RegPressureDelta &Delta,
- ArrayRef<PressureElement> CriticalPSets,
- ArrayRef<unsigned> MaxPressureLimit) {
+/// This is intended for speculative queries. It leaves pressure inconsistent
+/// with the current position, so must be restored by the caller.
+void RegPressureTracker::bumpDownwardPressure(const MachineInstr *MI) {
// Account for register pressure similar to RegPressureTracker::recede().
PhysRegOperands PhysRegOpers;
VirtRegOperands VirtRegOpers;
collectOperands(MI, PhysRegOpers, VirtRegOpers, TRI, RCI);
- // Snapshot Pressure.
- std::vector<unsigned> SavedPressure = CurrSetPressure;
- std::vector<unsigned> SavedMaxPressure = P.MaxSetPressure;
-
// Kill liveness at last uses. Assume allocatable physregs are single-use
// rather than checking LiveIntervals.
decreasePhysRegPressure(PhysRegOpers.Uses);
@@ -781,6 +785,23 @@
increaseVirtRegPressure(VirtRegOpers.DeadDefs);
decreasePhysRegPressure(PhysRegOpers.DeadDefs);
decreaseVirtRegPressure(VirtRegOpers.DeadDefs);
+}
+
+/// Consider the pressure increase caused by traversing this instruction
+/// top-down. Find the register class with the most change in its pressure limit
+/// based on the tracker's current pressure, and return the number of excess
+/// register units of that pressure set introduced by this instruction.
+///
+/// This assumes that the current LiveIn set is sufficient.
+void RegPressureTracker::
+getMaxDownwardPressureDelta(const MachineInstr *MI, RegPressureDelta &Delta,
+ ArrayRef<PressureElement> CriticalPSets,
+ ArrayRef<unsigned> MaxPressureLimit) {
+ // Snapshot Pressure.
+ std::vector<unsigned> SavedPressure = CurrSetPressure;
+ std::vector<unsigned> SavedMaxPressure = P.MaxSetPressure;
+
+ bumpDownwardPressure(MI);
computeExcessPressureDelta(SavedPressure, CurrSetPressure, Delta, TRI);
computeMaxPressureDelta(SavedMaxPressure, P.MaxSetPressure, CriticalPSets,
@@ -792,3 +813,29 @@
P.MaxSetPressure.swap(SavedMaxPressure);
CurrSetPressure.swap(SavedPressure);
}
+
+/// Get the pressure of each PSet after traversing this instruction bottom-up.
+void RegPressureTracker::
+getUpwardPressure(const MachineInstr *MI,
+ std::vector<unsigned> &PressureResult) {
+ // Snapshot pressure.
+ PressureResult = CurrSetPressure;
+
+ bumpUpwardPressure(MI);
+
+ // Current pressure becomes the result. Restore current pressure.
+ CurrSetPressure.swap(PressureResult);
+}
+
+/// Get the pressure of each PSet after traversing this instruction top-down.
+void RegPressureTracker::
+getDownwardPressure(const MachineInstr *MI,
+ std::vector<unsigned> &PressureResult) {
+ // Snapshot pressure.
+ PressureResult = CurrSetPressure;
+
+ bumpDownwardPressure(MI);
+
+ // Current pressure becomes the result. Restore current pressure.
+ CurrSetPressure.swap(PressureResult);
+}
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