Safeguard DBG_VALUE handling. Unbreaks the ASAN buildbot.

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

diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 1884452855b9fa4225da2f988694b1e98ac7148e..bdcef6ff12221ac3a85ea7f89109a5eefffafb0d 100644 (file)
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -29,6 +29,7 @@
 #include "llvm/CodeGen/LiveRangeEdit.h"
 #include "llvm/CodeGen/LiveRegMatrix.h"
 #include "llvm/CodeGen/LiveStackAnalysis.h"
+#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
 #include "llvm/CodeGen/MachineDominators.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineLoopInfo.h"
@@ -41,7 +42,6 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetOptions.h"
 #include <queue>
 
 using namespace llvm;
@@ -72,6 +72,7 @@ class RAGreedy : public MachineFunctionPass,
 
   // analyses
   SlotIndexes *Indexes;
+  MachineBlockFrequencyInfo *MBFI;
   MachineDominatorTree *DomTree;
   MachineLoopInfo *Loops;
   EdgeBundles *Bundles;
@@ -79,7 +80,7 @@ class RAGreedy : public MachineFunctionPass,
   LiveDebugVariables *DebugVars;
 
   // state
-  std::auto_ptr<Spiller> SpillerInstance;
+  OwningPtr<Spiller> SpillerInstance;
   std::priority_queue<std::pair<unsigned, unsigned> > Queue;
   unsigned NextCascade;
 
@@ -167,8 +168,8 @@ class RAGreedy : public MachineFunctionPass,
   };
 
   // splitting state.
-  std::auto_ptr<SplitAnalysis> SA;
-  std::auto_ptr<SplitEditor> SE;
+  OwningPtr<SplitAnalysis> SA;
+  OwningPtr<SplitEditor> SE;
 
   /// Cached per-block interference maps
   InterferenceCache IntfCache;
@@ -321,6 +322,8 @@ RAGreedy::RAGreedy(): MachineFunctionPass(ID) {
 
 void RAGreedy::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesCFG();
+  AU.addRequired<MachineBlockFrequencyInfo>();
+  AU.addPreserved<MachineBlockFrequencyInfo>();
   AU.addRequired<AliasAnalysis>();
   AU.addPreserved<AliasAnalysis>();
   AU.addRequired<LiveIntervals>();
@@ -632,16 +635,33 @@ unsigned RAGreedy::tryEvict(LiveInterval &VirtReg,
   // Keep track of the cheapest interference seen so far.
   EvictionCost BestCost(~0u);
   unsigned BestPhys = 0;
+  unsigned OrderLimit = Order.getOrder().size();
 
   // When we are just looking for a reduced cost per use, don't break any
   // hints, and only evict smaller spill weights.
   if (CostPerUseLimit < ~0u) {
     BestCost.BrokenHints = 0;
     BestCost.MaxWeight = VirtReg.weight;
+
+    // Check of any registers in RC are below CostPerUseLimit.
+    const TargetRegisterClass *RC = MRI->getRegClass(VirtReg.reg);
+    unsigned MinCost = RegClassInfo.getMinCost(RC);
+    if (MinCost >= CostPerUseLimit) {
+      DEBUG(dbgs() << RC->getName() << " minimum cost = " << MinCost
+                   << ", no cheaper registers to be found.\n");
+      return 0;
+    }
+
+    // It is normal for register classes to have a long tail of registers with
+    // the same cost. We don't need to look at them if they're too expensive.
+    if (TRI->getCostPerUse(Order.getOrder().back()) >= CostPerUseLimit) {
+      OrderLimit = RegClassInfo.getLastCostChange(RC);
+      DEBUG(dbgs() << "Only trying the first " << OrderLimit << " regs.\n");
+    }
   }
 
   Order.rewind();
-  while (unsigned PhysReg = Order.next()) {
+  while (unsigned PhysReg = Order.nextWithDups(OrderLimit)) {
     if (TRI->getCostPerUse(PhysReg) >= CostPerUseLimit)
       continue;
     // The first use of a callee-saved register in a function has cost 1.
@@ -697,7 +717,7 @@ bool RAGreedy::addSplitConstraints(InterferenceCache::Cursor Intf,
     Intf.moveToBlock(BC.Number);
     BC.Entry = BI.LiveIn ? SpillPlacement::PrefReg : SpillPlacement::DontCare;
     BC.Exit = BI.LiveOut ? SpillPlacement::PrefReg : SpillPlacement::DontCare;
-    BC.ChangesValue = BI.FirstDef;
+    BC.ChangesValue = BI.FirstDef.isValid();
 
     if (!Intf.hasInterference())
       continue;
@@ -1754,6 +1774,7 @@ bool RAGreedy::runOnMachineFunction(MachineFunction &mf) {
                      getAnalysis<LiveIntervals>(),
                      getAnalysis<LiveRegMatrix>());
   Indexes = &getAnalysis<SlotIndexes>();
+  MBFI = &getAnalysis<MachineBlockFrequencyInfo>();
   DomTree = &getAnalysis<MachineDominatorTree>();
   SpillerInstance.reset(createInlineSpiller(*this, *MF, *VRM));
   Loops = &getAnalysis<MachineLoopInfo>();
@@ -1762,7 +1783,7 @@ bool RAGreedy::runOnMachineFunction(MachineFunction &mf) {
   DebugVars = &getAnalysis<LiveDebugVariables>();
 
   SA.reset(new SplitAnalysis(*VRM, *LIS, *Loops));
-  SE.reset(new SplitEditor(*SA, *LIS, *VRM, *DomTree));
+  SE.reset(new SplitEditor(*SA, *LIS, *VRM, *DomTree, *MBFI));
   ExtraRegInfo.clear();
   ExtraRegInfo.resize(MRI->getNumVirtRegs());
   NextCascade = 1;