MI-Sched: Adjust regpressure limits for reserved regs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184564 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index 4ea0f9a..cb476e9 100644
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/lib/CodeGen/MachineScheduler.cpp
@@ -21,6 +21,7 @@
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/RegisterClassInfo.h"
#include "llvm/CodeGen/ScheduleDFS.h"
@@ -487,7 +488,7 @@
const std::vector<unsigned> &RegionPressure =
RPTracker.getPressure().MaxSetPressure;
for (unsigned i = 0, e = RegionPressure.size(); i < e; ++i) {
- unsigned Limit = TRI->getRegPressureSetLimit(i);
+ unsigned Limit = RegClassInfo->getRegPressureSetLimit(i);
DEBUG(dbgs() << TRI->getRegPressureSetName(i)
<< "Limit " << Limit
<< " Actual " << RegionPressure[i] << "\n");
@@ -513,7 +514,7 @@
}
DEBUG(
for (unsigned i = 0, e = NewMaxPressure.size(); i < e; ++i) {
- unsigned Limit = TRI->getRegPressureSetLimit(i);
+ unsigned Limit = RegClassInfo->getRegPressureSetLimit(i);
if (NewMaxPressure[i] > Limit ) {
dbgs() << " " << TRI->getRegPressureSetName(i) << ": "
<< NewMaxPressure[i] << " > " << Limit << "\n";
diff --git a/lib/CodeGen/RegisterClassInfo.cpp b/lib/CodeGen/RegisterClassInfo.cpp
index 87382d8..cacd7de 100644
--- a/lib/CodeGen/RegisterClassInfo.cpp
+++ b/lib/CodeGen/RegisterClassInfo.cpp
@@ -40,6 +40,9 @@
if (MF->getTarget().getRegisterInfo() != TRI) {
TRI = MF->getTarget().getRegisterInfo();
RegClass.reset(new RCInfo[TRI->getNumRegClasses()]);
+ unsigned NumPSets = TRI->getNumRegPressureSets();
+ PSetLimits.reset(new unsigned[NumPSets]);
+ std::fill(&PSetLimits[0], &PSetLimits[NumPSets], 0);
Update = true;
}
@@ -144,3 +147,32 @@
RCI.Tag = Tag;
}
+/// This is not accurate because two overlapping register sets may have some
+/// nonoverlapping reserved registers. However, computing the allocation order
+/// for all register classes would be too expensive.
+unsigned RegisterClassInfo::computePSetLimit(unsigned Idx) const {
+ const TargetRegisterClass *RC = 0;
+ unsigned NumRCUnits = 0;
+ for (TargetRegisterInfo::regclass_iterator
+ RI = TRI->regclass_begin(), RE = TRI->regclass_end(); RI != RE; ++RI) {
+ const int *PSetID = TRI->getRegClassPressureSets(*RI);
+ for (; *PSetID != -1; ++PSetID) {
+ if ((unsigned)*PSetID == Idx)
+ break;
+ }
+ if (*PSetID == -1)
+ continue;
+
+ // Found a register class that counts against this pressure set.
+ // For efficiency, only compute the set order for the largest set.
+ unsigned NUnits = TRI->getRegClassWeight(*RI).WeightLimit;
+ if (!RC || NUnits > NumRCUnits) {
+ RC = *RI;
+ NumRCUnits = NUnits;
+ }
+ }
+ compute(RC);
+ unsigned NReserved = RC->getNumRegs() - getNumAllocatableRegs(RC);
+ return TRI->getRegPressureSetLimit(Idx)
+ - TRI->getRegClassWeight(RC).RegWeight * NReserved;
+}
diff --git a/lib/CodeGen/RegisterPressure.cpp b/lib/CodeGen/RegisterPressure.cpp
index bdfd7fe..0141659 100644
--- a/lib/CodeGen/RegisterPressure.cpp
+++ b/lib/CodeGen/RegisterPressure.cpp
@@ -533,7 +533,7 @@
static void computeExcessPressureDelta(ArrayRef<unsigned> OldPressureVec,
ArrayRef<unsigned> NewPressureVec,
RegPressureDelta &Delta,
- const TargetRegisterInfo *TRI) {
+ const RegisterClassInfo *RCI) {
int ExcessUnits = 0;
unsigned PSetID = ~0U;
for (unsigned i = 0, e = OldPressureVec.size(); i < e; ++i) {
@@ -543,7 +543,7 @@
if (!PDiff) // No change in this set in the common case.
continue;
// Only consider change beyond the limit.
- unsigned Limit = TRI->getRegPressureSetLimit(i);
+ unsigned Limit = RCI->getRegPressureSetLimit(i);
if (Limit > POld) {
if (Limit > PNew)
PDiff = 0; // Under the limit
@@ -659,7 +659,7 @@
bumpUpwardPressure(MI);
- computeExcessPressureDelta(SavedPressure, CurrSetPressure, Delta, TRI);
+ computeExcessPressureDelta(SavedPressure, CurrSetPressure, Delta, RCI);
computeMaxPressureDelta(SavedMaxPressure, P.MaxSetPressure, CriticalPSets,
MaxPressureLimit, Delta);
assert(Delta.CriticalMax.UnitIncrease >= 0 &&
@@ -749,7 +749,7 @@
bumpDownwardPressure(MI);
- computeExcessPressureDelta(SavedPressure, CurrSetPressure, Delta, TRI);
+ computeExcessPressureDelta(SavedPressure, CurrSetPressure, Delta, RCI);
computeMaxPressureDelta(SavedMaxPressure, P.MaxSetPressure, CriticalPSets,
MaxPressureLimit, Delta);
assert(Delta.CriticalMax.UnitIncrease >= 0 &&