X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FRegAllocGreedy.cpp;h=9eed1fc62accc2381c7c41b4ff6150c9bc287690;hb=c496875f0c205ffadcec8060e1170e1c58e4eb55;hp=1884452855b9fa4225da2f988694b1e98ac7148e;hpb=f7999fe1cb2c2bdb0a4080efabb4743719ce45ca;p=oota-llvm.git

diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 1884452855b..9eed1fc62ac 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -41,7 +41,6 @@
 #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;
@@ -79,7 +78,7 @@ 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 +166,8 @@ 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;
@@ -632,16 +631,33 @@ 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.