3 files changed, 39 insertions, 10 deletions
diff --git a/include/llvm/CodeGen/LiveInterval.h b/include/llvm/CodeGen/LiveInterval.h
index d6f5c84..f1ae587 100644
--- a/include/llvm/CodeGen/LiveInterval.h
+++ b/include/llvm/CodeGen/LiveInterval.h
@@ -113,6 +113,26 @@ namespace llvm {
     VNInfoList valnos;   // value#'s
 
   public:
+    
+    struct InstrSlots {
+      enum {
+        LOAD  = 0,
+        USE   = 1,
+        DEF   = 2,
+        STORE = 3,
+        NUM   = 4
+      };
+
+      static unsigned scale(unsigned slot, unsigned factor) {
+        unsigned index = slot / NUM,
+                 offset = slot % NUM;
+        assert(index <= ~0U / (factor * NUM) &&
+               "Rescaled interval would overflow");
+        return index * NUM * factor + offset;
+      }
+
+    };
+
     LiveInterval(unsigned Reg, float Weight, bool IsSS = false)
       : reg(Reg), weight(Weight), preference(0)  {
       if (IsSS)
@@ -414,6 +434,10 @@ namespace llvm {
     /// Also remove the value# from value# list.
     void removeValNo(VNInfo *ValNo);
 
+    /// scaleNumbering - Renumber VNI and ranges to provide gaps for new
+    /// instructions.
+    void scaleNumbering(unsigned factor);
+
     /// getSize - Returns the sum of sizes of all the LiveRange's.
     ///
     unsigned getSize() const;
diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index 01ea609..7c44cc7 100644
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -92,20 +92,12 @@ namespace llvm {
 
     std::vector<MachineInstr*> ClonedMIs;
 
+    typedef LiveInterval::InstrSlots InstrSlots;
+
   public:
     static char ID; // Pass identification, replacement for typeid
     LiveIntervals() : MachineFunctionPass(&ID) {}
 
-    struct InstrSlots {
-      enum {
-        LOAD  = 0,
-        USE   = 1,
-        DEF   = 2,
-        STORE = 3,
-        NUM   = 4
-      };
-    };
-
     static unsigned getBaseIndex(unsigned index) {
       return index - (index % InstrSlots::NUM);
     }
@@ -226,6 +218,13 @@ namespace llvm {
       return getInstructionFromIndex(Index) == 0;
     }
 
+    /// hasGapAfterInstr - Return true if the successive instruction slot,
+    /// i.e. Index + InstrSlots::Num, is not occupied.
+    bool hasGapAfterInstr(unsigned Index) {
+      Index = getBaseIndex(Index + InstrSlots::NUM);
+      return getInstructionFromIndex(Index) == 0;
+    }
+
     /// findGapBeforeInstr - Find an empty instruction slot before the
     /// specified index. If "Furthest" is true, find one that's furthest
     /// away from the index (but before any index that's occupied).
@@ -394,6 +393,10 @@ namespace llvm {
     /// computeNumbering - Compute the index numbering.
     void computeNumbering();
 
+    /// scaleNumbering - Rescale interval numbers to introduce gaps for new
+    /// instructions
+    void scaleNumbering(int factor);
+
     /// intervalIsInOneMBB - Returns true if the specified interval is entirely
     /// within a single basic block.
     bool intervalIsInOneMBB(const LiveInterval &li) const;
diff --git a/include/llvm/CodeGen/LiveStackAnalysis.h b/include/llvm/CodeGen/LiveStackAnalysis.h
index a2a2f93..27ae1be 100644
--- a/include/llvm/CodeGen/LiveStackAnalysis.h
+++ b/include/llvm/CodeGen/LiveStackAnalysis.h
@@ -48,6 +48,8 @@ namespace llvm {
     iterator begin() { return S2IMap.begin(); }
     iterator end() { return S2IMap.end(); }
 
+    void scaleNumbering(int factor);
+
     unsigned getNumIntervals() const { return (unsigned)S2IMap.size(); }
 
     LiveInterval &getOrCreateInterval(int Slot, const TargetRegisterClass *RC) {