X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FMachineSink.cpp;h=b117f8c3a206c9982e14fc79c41a638cea57fd4e;hb=feab72c20acc97f8942148189c06e443b29df841;hp=1ce546b578add839577f8caeb6f0e875b7cd1185;hpb=1dd8c8560d45d36a8e507cd014352f1d313f9f9e;p=oota-llvm.git

diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index 1ce546b578a..b117f8c3a20 100644
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -49,7 +49,6 @@ namespace {
     MachineDominatorTree *DT;   // Machine dominator tree
     MachineLoopInfo *LI;
     AliasAnalysis *AA;
-    BitVector AllocatableSet;   // Which physregs are allocatable?
 
     // Remember which edges have been considered for breaking.
     SmallSet<std::pair<MachineBasicBlock*,MachineBasicBlock*>, 8>
@@ -99,6 +98,16 @@ namespace {
     bool PerformTrivialForwardCoalescing(MachineInstr *MI,
                                          MachineBasicBlock *MBB);
   };
+
+  // SuccessorSorter - Sort Successors according to their loop depth. 
+  struct SuccessorSorter {
+    SuccessorSorter(MachineLoopInfo *LoopInfo) : LI(LoopInfo) {}
+    bool operator()(const MachineBasicBlock *LHS,
+                    const MachineBasicBlock *RHS) const {
+      return LI->getLoopDepth(LHS) < LI->getLoopDepth(RHS);
+    }
+    MachineLoopInfo *LI;
+  };
 } // end anonymous namespace
 
 char MachineSinking::ID = 0;
@@ -219,7 +228,6 @@ bool MachineSinking::runOnMachineFunction(MachineFunction &MF) {
   DT = &getAnalysis<MachineDominatorTree>();
   LI = &getAnalysis<MachineLoopInfo>();
   AA = &getAnalysis<AliasAnalysis>();
-  AllocatableSet = TRI->getAllocatableSet(MF);
 
   bool EverMadeChange = false;
 
@@ -526,8 +534,11 @@ MachineBasicBlock *MachineSinking::FindSuccToSinkTo(MachineInstr *MI,
 
       // Otherwise, we should look at all the successors and decide which one
       // we should sink to.
-      for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
-           E = MBB->succ_end(); SI != E; ++SI) {
+      // We give successors with smaller loop depth higher priority.
+      SmallVector<MachineBasicBlock*, 4> Succs(MBB->succ_begin(), MBB->succ_end());
+      std::stable_sort(Succs.begin(), Succs.end(), SuccessorSorter(LI));
+      for (SmallVector<MachineBasicBlock*, 4>::iterator SI = Succs.begin(),
+           E = Succs.end(); SI != E; ++SI) {
         MachineBasicBlock *SuccBlock = *SI;
         bool LocalUse = false;
         if (AllUsesDominatedByBlock(Reg, SuccBlock, MBB,