Don't assert if we can't constant fold extract/insertvalue

[oota-llvm.git] / include / llvm / CodeGen / CalcSpillWeights.h

diff --git a/include/llvm/CodeGen/CalcSpillWeights.h b/include/llvm/CodeGen/CalcSpillWeights.h
index 24264d7f97f0e7177df61c911f3924e106c0ceb6..c8ec76410ce71507937c2a3a8e1507f9eed4517e 100644 (file)
--- a/include/llvm/CodeGen/CalcSpillWeights.h
+++ b/include/llvm/CodeGen/CalcSpillWeights.h
@@ -11,31 +11,46 @@
 #ifndef LLVM_CODEGEN_CALCSPILLWEIGHTS_H
 #define LLVM_CODEGEN_CALCSPILLWEIGHTS_H
 
-#include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/CodeGen/SlotIndexes.h"
 
 namespace llvm {
 
   class LiveInterval;
   class LiveIntervals;
+  class MachineBlockFrequencyInfo;
   class MachineLoopInfo;
 
+  /// normalizeSpillWeight - The spill weight of a live interval is computed as:
+  ///
+  ///   (sum(use freq) + sum(def freq)) / (K + size)
+  ///
+  /// @param UseDefFreq Expected number of executed use and def instructions
+  ///                   per function call. Derived from block frequencies.
+  /// @param Size       Size of live interval as returnexd by getSize()
+  ///
+  static inline float normalizeSpillWeight(float UseDefFreq, unsigned Size) {
+    // The constant 25 instructions is added to avoid depending too much on
+    // accidental SlotIndex gaps for small intervals. The effect is that small
+    // intervals have a spill weight that is mostly proportional to the number
+    // of uses, while large intervals get a spill weight that is closer to a use
+    // density.
+    return UseDefFreq / (Size + 25*SlotIndex::InstrDist);
+  }
+
   /// VirtRegAuxInfo - Calculate auxiliary information for a virtual
   /// register such as its spill weight and allocation hint.
   class VirtRegAuxInfo {
-    MachineFunction &mf_;
-    LiveIntervals &lis_;
-    const MachineLoopInfo &loops_;
-    DenseMap<unsigned, float> hint_;
+    MachineFunction &MF;
+    LiveIntervals &LIS;
+    const MachineLoopInfo &Loops;
+    const MachineBlockFrequencyInfo &MBFI;
+    DenseMap<unsigned, float> Hint;
   public:
     VirtRegAuxInfo(MachineFunction &mf, LiveIntervals &lis,
-                   const MachineLoopInfo &loops) :
-      mf_(mf), lis_(lis), loops_(loops) {}
-
-    /// CalculateRegClass - recompute the register class for reg from its uses.
-    /// Since the register class can affect the allocation hint, this function
-    /// should be called before CalculateWeightAndHint if both are called.
-    void CalculateRegClass(unsigned reg);
+                   const MachineLoopInfo &loops,
+                   const MachineBlockFrequencyInfo &mbfi)
+        : MF(mf), LIS(lis), Loops(loops), MBFI(mbfi) {}
 
     /// CalculateWeightAndHint - (re)compute li's spill weight and allocation
     /// hint.