Initial support for Neon scalar instructions.

[oota-llvm.git] / lib / CodeGen / RegisterPressure.cpp

diff --git a/lib/CodeGen/RegisterPressure.cpp b/lib/CodeGen/RegisterPressure.cpp
index 8328b500af16a3fc5751a7b7a8377bd143b5ca8f..260eacdca66b65a05b4686486e5a701aff990317 100644 (file)
--- a/lib/CodeGen/RegisterPressure.cpp
+++ b/lib/CodeGen/RegisterPressure.cpp
@@ -153,6 +153,24 @@ const LiveInterval *RegPressureTracker::getInterval(unsigned Reg) const {
   return LIS->getCachedRegUnit(Reg);
 }
 
+void RegPressureTracker::reset() {
+  MBB = 0;
+  LIS = 0;
+
+  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();
@@ -496,11 +511,17 @@ bool RegPressureTracker::recede(PressureDiff *PDiff) {
       // Adjust liveouts if LiveIntervals are available.
       if (RequireIntervals) {
         const LiveInterval *LI = getInterval(Reg);
-        if (LI && !LI->isKilledAtInstr(SlotIdx))
-          discoverLiveOut(Reg);
+        // Check if this LR is killed and not redefined here.
+        if (LI) {
+          LiveRangeQuery LRQ(*LI, SlotIdx);
+          if (!LRQ.isKill() && !LRQ.valueDefined())
+            discoverLiveOut(Reg);
+        }
       }
       increaseRegPressure(Reg);
       LiveRegs.insert(Reg);
+      if (LiveUses && !containsReg(*LiveUses, Reg))
+        LiveUses->push_back(Reg);
     }
   }
   if (TrackUntiedDefs) {
@@ -550,7 +571,7 @@ bool RegPressureTracker::advance() {
     bool lastUse = false;
     if (RequireIntervals) {
       const LiveInterval *LI = getInterval(Reg);
-      lastUse = LI && LI->isKilledAtInstr(SlotIdx);
+      lastUse = LI && LiveRangeQuery(*LI, SlotIdx).isKill();
     }
     else {
       // Allocatable physregs are always single-use before register rewriting.
@@ -773,22 +794,10 @@ 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();
@@ -886,9 +895,10 @@ void RegPressureTracker::bumpDownwardPressure(const MachineInstr *MI) {
       // 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);
+      if (LI) {
+        LiveRangeQuery LRQ(*LI, SlotIdx);
+        if (LRQ.isKill() && !findUseBetween(Reg, CurrIdx, SlotIdx, MRI, LIS))
+          decreaseRegPressure(Reg);
       }
     }
     else if (!TargetRegisterInfo::isVirtualRegister(Reg)) {