X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FRegisterPressure.cpp;h=b2909e0a226dad3b858adfc795575374043863fe;hb=e8d18694cbee58ffd7137014e89200fc424e3b78;hp=8328b500af16a3fc5751a7b7a8377bd143b5ca8f;hpb=1362dcb5899bc88f0e567dd10e2e9003a79ace21;p=oota-llvm.git

diff --git a/lib/CodeGen/RegisterPressure.cpp b/lib/CodeGen/RegisterPressure.cpp
index 8328b500af1..b2909e0a226 100644
--- a/lib/CodeGen/RegisterPressure.cpp
+++ b/lib/CodeGen/RegisterPressure.cpp
@@ -147,12 +147,30 @@ void RegionPressure::openBottom(MachineBasicBlock::const_iterator PrevBottom) {
   LiveInRegs.clear();
 }
 
-const LiveInterval *RegPressureTracker::getInterval(unsigned Reg) const {
+const LiveRange *RegPressureTracker::getLiveRange(unsigned Reg) const {
   if (TargetRegisterInfo::isVirtualRegister(Reg))
     return &LIS->getInterval(Reg);
   return LIS->getCachedRegUnit(Reg);
 }
 
+void RegPressureTracker::reset() {
+  MBB = nullptr;
+  LIS = nullptr;
+
+  CurrSetPressure.clear();
+  LiveThruPressure.clear();
+  P.MaxSetPressure.clear();
+
+  if (RequireIntervals)
+    static_cast<IntervalPressure&>(P).reset();
+  else
+    static_cast<RegionPressure&>(P).reset();
+
+  LiveRegs.PhysRegs.clear();
+  LiveRegs.VirtRegs.clear();
+  UntiedDefs.clear();
+}
+
 /// Setup the RegPressureTracker.
 ///
 /// TODO: Add support for pressure without LiveIntervals.
@@ -163,6 +181,8 @@ void RegPressureTracker::init(const MachineFunction *mf,
                               MachineBasicBlock::const_iterator pos,
                               bool ShouldTrackUntiedDefs)
 {
+  reset();
+
   MF = mf;
   TRI = MF->getTarget().getRegisterInfo();
   RCI = rci;
@@ -177,19 +197,11 @@ void RegPressureTracker::init(const MachineFunction *mf,
 
   CurrPos = pos;
   CurrSetPressure.assign(TRI->getNumRegPressureSets(), 0);
-  LiveThruPressure.clear();
 
-  if (RequireIntervals)
-    static_cast<IntervalPressure&>(P).reset();
-  else
-    static_cast<RegionPressure&>(P).reset();
   P.MaxSetPressure = CurrSetPressure;
 
-  LiveRegs.PhysRegs.clear();
   LiveRegs.PhysRegs.setUniverse(TRI->getNumRegs());
-  LiveRegs.VirtRegs.clear();
   LiveRegs.VirtRegs.setUniverse(MRI->getNumVirtRegs());
-  UntiedDefs.clear();
   if (TrackUntiedDefs)
     UntiedDefs.setUniverse(MRI->getNumVirtRegs());
 }
@@ -399,10 +411,9 @@ static void collectPDiff(PressureDiff &PDiff, RegisterOperands &RegOpers,
                          const MachineRegisterInfo *MRI) {
   assert(!PDiff.begin()->isValid() && "stale PDiff");
 
-  for (unsigned i = 0, e = RegOpers.Defs.size(); i != e; ++i) {
-    if (!containsReg(RegOpers.Uses, RegOpers.Defs[i]))
-      PDiff.addPressureChange(RegOpers.Defs[i], true, MRI);
-  }
+  for (unsigned i = 0, e = RegOpers.Defs.size(); i != e; ++i)
+    PDiff.addPressureChange(RegOpers.Defs[i], true, MRI);
+
   for (unsigned i = 0, e = RegOpers.Uses.size(); i != e; ++i)
     PDiff.addPressureChange(RegOpers.Uses[i], false, MRI);
 }
@@ -437,9 +448,13 @@ void RegPressureTracker::discoverLiveOut(unsigned Reg) {
   increaseSetPressure(P.MaxSetPressure, MRI->getPressureSets(Reg));
 }
 
-/// Recede across the previous instruction.
-/// Record the pressure difference if it is provided.
-bool RegPressureTracker::recede(PressureDiff *PDiff) {
+/// Recede across the previous instruction. If LiveUses is provided, record any
+/// RegUnits that are made live by the current instruction's uses. This includes
+/// registers that are both defined and used by the instruction.  If a pressure
+/// difference pointer is provided record the changes is pressure caused by this
+/// instruction independent of liveness.
+bool RegPressureTracker::recede(SmallVectorImpl<unsigned> *LiveUses,
+                                PressureDiff *PDiff) {
   // Check for the top of the analyzable region.
   if (CurrPos == MBB->begin()) {
     closeRegion();
@@ -483,10 +498,26 @@ bool RegPressureTracker::recede(PressureDiff *PDiff) {
   // TODO: consider earlyclobbers?
   for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) {
     unsigned Reg = RegOpers.Defs[i];
-    if (LiveRegs.erase(Reg))
-      decreaseRegPressure(Reg);
-    else
-      discoverLiveOut(Reg);
+    bool DeadDef = false;
+    if (RequireIntervals) {
+      const LiveRange *LR = getLiveRange(Reg);
+      if (LR) {
+        LiveQueryResult LRQ = LR->Query(SlotIdx);
+        DeadDef = LRQ.isDeadDef();
+      }
+    }
+    if (DeadDef) {
+      // LiveIntervals knows this is a dead even though it's MachineOperand is
+      // not flagged as such. Since this register will not be recorded as
+      // live-out, increase its PDiff value to avoid underflowing pressure.
+      if (PDiff)
+        PDiff->addPressureChange(Reg, false, MRI);
+    } else {
+      if (LiveRegs.erase(Reg))
+        decreaseRegPressure(Reg);
+      else
+        discoverLiveOut(Reg);
+    }
   }
 
   // Generate liveness for uses.
@@ -495,12 +526,17 @@ bool RegPressureTracker::recede(PressureDiff *PDiff) {
     if (!LiveRegs.contains(Reg)) {
       // Adjust liveouts if LiveIntervals are available.
       if (RequireIntervals) {
-        const LiveInterval *LI = getInterval(Reg);
-        if (LI && !LI->isKilledAtInstr(SlotIdx))
-          discoverLiveOut(Reg);
+        const LiveRange *LR = getLiveRange(Reg);
+        if (LR) {
+          LiveQueryResult LRQ = LR->Query(SlotIdx);
+          if (!LRQ.isKill() && !LRQ.valueDefined())
+            discoverLiveOut(Reg);
+        }
       }
       increaseRegPressure(Reg);
       LiveRegs.insert(Reg);
+      if (LiveUses && !containsReg(*LiveUses, Reg))
+        LiveUses->push_back(Reg);
     }
   }
   if (TrackUntiedDefs) {
@@ -549,8 +585,8 @@ bool RegPressureTracker::advance() {
     // Kill liveness at last uses.
     bool lastUse = false;
     if (RequireIntervals) {
-      const LiveInterval *LI = getInterval(Reg);
-      lastUse = LI && LI->isKilledAtInstr(SlotIdx);
+      const LiveRange *LR = getLiveRange(Reg);
+      lastUse = LR && LR->Query(SlotIdx).isKill();
     }
     else {
       // Allocatable physregs are always single-use before register rewriting.
@@ -682,8 +718,19 @@ void RegPressureTracker::bumpUpwardPressure(const MachineInstr *MI) {
   // Kill liveness at live defs.
   for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) {
     unsigned Reg = RegOpers.Defs[i];
-    if (!containsReg(RegOpers.Uses, Reg))
-      decreaseRegPressure(Reg);
+    bool DeadDef = false;
+    if (RequireIntervals) {
+      const LiveRange *LR = getLiveRange(Reg);
+      if (LR) {
+        SlotIndex SlotIdx = LIS->getInstructionIndex(MI);
+        LiveQueryResult LRQ = LR->Query(SlotIdx);
+        DeadDef = LRQ.isDeadDef();
+      }
+    }
+    if (!DeadDef) {
+      if (!containsReg(RegOpers.Uses, Reg))
+        decreaseRegPressure(Reg);
+    }
   }
   // Generate liveness for uses.
   for (unsigned i = 0, e = RegOpers.Uses.size(); i < e; ++i) {
@@ -773,22 +820,10 @@ getMaxUpwardPressureDelta(const MachineInstr *MI, PressureDiff *PDiff,
 /// @param MaxPressureLimit Is the max pressure within the region, not
 /// necessarily at the current position.
 void RegPressureTracker::
-getUpwardPressureDelta(const MachineInstr *MI, /*const*/ PressureDiff &PDiff1,
+getUpwardPressureDelta(const MachineInstr *MI, /*const*/ PressureDiff &PDiff,
                        RegPressureDelta &Delta,
                        ArrayRef<PressureChange> CriticalPSets,
                        ArrayRef<unsigned> MaxPressureLimit) const {
-  RegisterOperands RegOpers(TRI, MRI, /*IgnoreDead=*/true);
-  collectOperands(MI, RegOpers);
-
-  // Decrease the pressure change for live uses.
-  PressureDiff PDiff = PDiff1;
-  for (unsigned i = 0, e = RegOpers.Uses.size(); i != e; ++i) {
-    if (LiveRegs.contains(RegOpers.Uses[i]))
-      PDiff.addPressureChange(RegOpers.Uses[i], true, MRI);
-  }
-
-  // Now directly query pressure from PDiff. Everything above this can be
-  // cached and updated independent of the query.
   unsigned CritIdx = 0, CritEnd = CriticalPSets.size();
   for (PressureDiff::const_iterator
          PDiffI = PDiff.begin(), PDiffE = PDiff.end();
@@ -847,9 +882,9 @@ static bool findUseBetween(unsigned Reg,
                            SlotIndex PriorUseIdx, SlotIndex NextUseIdx,
                            const MachineRegisterInfo *MRI,
                            const LiveIntervals *LIS) {
-  for (MachineRegisterInfo::use_nodbg_iterator
-         UI = MRI->use_nodbg_begin(Reg), UE = MRI->use_nodbg_end();
-         UI != UE; UI.skipInstruction()) {
+  for (MachineRegisterInfo::use_instr_nodbg_iterator
+       UI = MRI->use_instr_nodbg_begin(Reg),
+       UE = MRI->use_instr_nodbg_end(); UI != UE; ++UI) {
       const MachineInstr* MI = &*UI;
       if (MI->isDebugValue())
         continue;
@@ -885,10 +920,12 @@ void RegPressureTracker::bumpDownwardPressure(const MachineInstr *MI) {
       // FIXME: allow the caller to pass in the list of vreg uses that remain
       // to be bottom-scheduled to avoid searching uses at each query.
       SlotIndex CurrIdx = getCurrSlot();
-      const LiveInterval *LI = getInterval(Reg);
-      if (LI && LI->isKilledAtInstr(SlotIdx)
-          && !findUseBetween(Reg, CurrIdx, SlotIdx, MRI, LIS)) {
-        decreaseRegPressure(Reg);
+      const LiveRange *LR = getLiveRange(Reg);
+      if (LR) {
+        LiveQueryResult LRQ = LR->Query(SlotIdx);
+        if (LRQ.isKill() && !findUseBetween(Reg, CurrIdx, SlotIdx, MRI, LIS)) {
+          decreaseRegPressure(Reg);
+        }
       }
     }
     else if (!TargetRegisterInfo::isVirtualRegister(Reg)) {