X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FInlineSpiller.cpp;h=28235b0f973d36f1689af48991972868f102b11e;hb=487ecab8d41e70700ca27895127b99f955e31fd0;hp=5bf7b112869db2fd136809ffa2b939b4ea550000;hpb=757ed6daf4c7720cddebdc3f502f7ecb110ded72;p=oota-llvm.git

diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp
index 5bf7b112869..28235b0f973 100644
--- a/lib/CodeGen/InlineSpiller.cpp
+++ b/lib/CodeGen/InlineSpiller.cpp
@@ -12,7 +12,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "regalloc"
 #include "Spiller.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/Statistic.h"
@@ -22,6 +21,7 @@
 #include "llvm/CodeGen/LiveRangeEdit.h"
 #include "llvm/CodeGen/LiveStackAnalysis.h"
 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
+#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
 #include "llvm/CodeGen/MachineDominators.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
@@ -38,6 +38,8 @@
 
 using namespace llvm;
 
+#define DEBUG_TYPE "regalloc"
+
 STATISTIC(NumSpilledRanges,   "Number of spilled live ranges");
 STATISTIC(NumSnippets,        "Number of spilled snippets");
 STATISTIC(NumSpills,          "Number of spills inserted");
@@ -120,7 +122,7 @@ public:
 
     SibValueInfo(unsigned Reg, VNInfo *VNI)
       : AllDefsAreReloads(true), DefByOrigPHI(false), KillsSource(false),
-        SpillReg(Reg), SpillVNI(VNI), SpillMBB(0), DefMI(0) {}
+        SpillReg(Reg), SpillVNI(VNI), SpillMBB(nullptr), DefMI(nullptr) {}
 
     // Returns true when a def has been found.
     bool hasDef() const { return DefByOrigPHI || DefMI; }
@@ -137,21 +139,16 @@ private:
   ~InlineSpiller() {}
 
 public:
-  InlineSpiller(MachineFunctionPass &pass,
-                MachineFunction &mf,
-                VirtRegMap &vrm)
-    : MF(mf),
-      LIS(pass.getAnalysis<LiveIntervals>()),
-      LSS(pass.getAnalysis<LiveStacks>()),
-      AA(&pass.getAnalysis<AliasAnalysis>()),
-      MDT(pass.getAnalysis<MachineDominatorTree>()),
-      Loops(pass.getAnalysis<MachineLoopInfo>()),
-      VRM(vrm),
-      MFI(*mf.getFrameInfo()),
-      MRI(mf.getRegInfo()),
-      TII(*mf.getTarget().getInstrInfo()),
-      TRI(*mf.getTarget().getRegisterInfo()),
-      MBFI(pass.getAnalysis<MachineBlockFrequencyInfo>()) {}
+  InlineSpiller(MachineFunctionPass &pass, MachineFunction &mf, VirtRegMap &vrm)
+      : MF(mf), LIS(pass.getAnalysis<LiveIntervals>()),
+        LSS(pass.getAnalysis<LiveStacks>()),
+        AA(&pass.getAnalysis<AliasAnalysis>()),
+        MDT(pass.getAnalysis<MachineDominatorTree>()),
+        Loops(pass.getAnalysis<MachineLoopInfo>()), VRM(vrm),
+        MFI(*mf.getFrameInfo()), MRI(mf.getRegInfo()),
+        TII(*mf.getSubtarget().getInstrInfo()),
+        TRI(*mf.getSubtarget().getRegisterInfo()),
+        MBFI(pass.getAnalysis<MachineBlockFrequencyInfo>()) {}
 
   void spill(LiveRangeEdit &) override;
 
@@ -166,7 +163,7 @@ private:
 
   bool isSibling(unsigned Reg);
   MachineInstr *traceSiblingValue(unsigned, VNInfo*, VNInfo*);
-  void propagateSiblingValue(SibValueMap::iterator, VNInfo *VNI = 0);
+  void propagateSiblingValue(SibValueMap::iterator, VNInfo *VNI = nullptr);
   void analyzeSiblingValues();
 
   bool hoistSpill(LiveInterval &SpillLI, MachineInstr *CopyMI);
@@ -178,7 +175,7 @@ private:
 
   bool coalesceStackAccess(MachineInstr *MI, unsigned Reg);
   bool foldMemoryOperand(ArrayRef<std::pair<MachineInstr*, unsigned> >,
-                         MachineInstr *LoadMI = 0);
+                         MachineInstr *LoadMI = nullptr);
   void insertReload(unsigned VReg, SlotIndex, MachineBasicBlock::iterator MI);
   void insertSpill(unsigned VReg, bool isKill, MachineBasicBlock::iterator MI);
 
@@ -235,7 +232,7 @@ bool InlineSpiller::isSnippet(const LiveInterval &SnipLI) {
   if (SnipLI.getNumValNums() > 2 || !LIS.intervalIsInOneMBB(SnipLI))
     return false;
 
-  MachineInstr *UseMI = 0;
+  MachineInstr *UseMI = nullptr;
 
   // Check that all uses satisfy our criteria.
   for (MachineRegisterInfo::reg_instr_nodbg_iterator
@@ -366,7 +363,7 @@ void InlineSpiller::propagateSiblingValue(SibValueMap::iterator SVIIter,
   do {
     SVI = WorkList.pop_back_val();
     TinyPtrVector<VNInfo*> *Deps = VNI ? &FirstDeps : &SVI->second.Deps;
-    VNI = 0;
+    VNI = nullptr;
 
     SibValueInfo &SV = SVI->second;
     if (!SV.SpillMBB)
@@ -440,7 +437,20 @@ void InlineSpiller::propagateSiblingValue(SibValueMap::iterator SVIIter,
           // Also hoist spills to blocks with smaller loop depth, but make sure
           // that the new value dominates.  Non-phi dependents are always
           // dominated, phis need checking.
+
+          const BranchProbability MarginProb(4, 5); // 80%
+          // Hoist a spill to outer loop if there are multiple dependents (it
+          // can be beneficial if more than one dependents are hoisted) or
+          // if DepSV (the hoisting source) is hotter than SV (the hoisting
+          // destination) (we add a 80% margin to bias a little towards
+          // loop depth).
+          bool HoistCondition =
+            (MBFI.getBlockFreq(DepSV.SpillMBB) >=
+             (MBFI.getBlockFreq(SV.SpillMBB) * MarginProb)) ||
+            Deps->size() > 1;
+
           if ((Loops.getLoopDepth(DepSV.SpillMBB) > SpillDepth) &&
+              HoistCondition &&
               (!DepSVI->first->isPHIDef() ||
                MDT.dominates(SV.SpillMBB, DepSV.SpillMBB))) {
             Changed = true;
@@ -645,7 +655,7 @@ void InlineSpiller::analyzeSiblingValues() {
       VNInfo *VNI = *VI;
       if (VNI->isUnused())
         continue;
-      MachineInstr *DefMI = 0;
+      MachineInstr *DefMI = nullptr;
       if (!VNI->isPHIDef()) {
        DefMI = LIS.getInstructionFromIndex(VNI->def);
        assert(DefMI && "No defining instruction");
@@ -1196,7 +1206,7 @@ void InlineSpiller::spillAroundUses(unsigned Reg) {
   for (MachineRegisterInfo::reg_bundle_iterator
        RegI = MRI.reg_bundle_begin(Reg), E = MRI.reg_bundle_end();
        RegI != E; ) {
-    MachineInstr *MI = getBundleStart(&*(RegI++));
+    MachineInstr *MI = &*(RegI++);
 
     // Debug values are not allowed to affect codegen.
     if (MI->isDebugValue()) {
@@ -1345,7 +1355,7 @@ void InlineSpiller::spill(LiveRangeEdit &edit) {
   // Share a stack slot among all descendants of Original.
   Original = VRM.getOriginal(edit.getReg());
   StackSlot = VRM.getStackSlot(Original);
-  StackInt = 0;
+  StackInt = nullptr;
 
   DEBUG(dbgs() << "Inline spilling "
                << MRI.getRegClass(edit.getReg())->getName()