5 files changed, 27 insertions, 6 deletions
diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index d7ff8da02a..294eb25fb2 100644
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -74,6 +74,14 @@ namespace llvm {
       return (isDef + isUse) * powf(10.0F, (float)loopDepth);
     }
 
+    // After summing the spill weights of all defs and uses, the final weight
+    // should be normalized, dividing the weight of the interval by its size.
+    // This encourages spilling of intervals that are large and have few uses,
+    // and discourages spilling of small intervals with many uses.
+    void normalizeSpillWeight(LiveInterval &li) {
+      li.weight /= getApproximateInstructionCount(li) + 25;
+    }
+
     typedef Reg2IntervalMap::iterator iterator;
     typedef Reg2IntervalMap::const_iterator const_iterator;
     const_iterator begin() const { return r2iMap_.begin(); }
@@ -409,6 +417,9 @@ namespace llvm {
         DenseMap<unsigned,unsigned> &MBBVRegsMap,
         std::vector<LiveInterval*> &NewLIs);
 
+    // Normalize the spill weight of all the intervals in NewLIs.
+    void normalizeSpillWeights(std::vector<LiveInterval*> &NewLIs);
+
     static LiveInterval* createInterval(unsigned Reg);
 
     void printInstrs(raw_ostream &O) const;
diff --git a/lib/CodeGen/CalcSpillWeights.cpp b/lib/CodeGen/CalcSpillWeights.cpp
index 2bedd04243..a328d0e556 100644
--- a/lib/CodeGen/CalcSpillWeights.cpp
+++ b/lib/CodeGen/CalcSpillWeights.cpp
@@ -131,10 +131,7 @@ bool CalculateSpillWeights::runOnMachineFunction(MachineFunction &fn) {
       if (Hint.first || Hint.second)
         li.weight *= 1.01F;
 
-      // Divide the weight of the interval by its size.  This encourages
-      // spilling of intervals that are large and have few uses, and
-      // discourages spilling of small intervals with many uses.
-      li.weight /= lis->getApproximateInstructionCount(li) * SlotIndex::NUM;
+      lis->normalizeSpillWeight(li);
     }
   }
   
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index f6bf433940..0b38ffb970 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -1562,6 +1562,12 @@ LiveIntervals::handleSpilledImpDefs(const LiveInterval &li, VirtRegMap &vrm,
   }
 }
 
+void
+LiveIntervals::normalizeSpillWeights(std::vector<LiveInterval*> &NewLIs) {
+  for (unsigned i = 0, e = NewLIs.size(); i != e; ++i)
+    normalizeSpillWeight(*NewLIs[i]);
+}
+
 std::vector<LiveInterval*> LiveIntervals::
 addIntervalsForSpillsFast(const LiveInterval &li,
                           const MachineLoopInfo *loopInfo,
@@ -1739,6 +1745,7 @@ addIntervalsForSpills(const LiveInterval &li,
     }
 
     handleSpilledImpDefs(li, vrm, rc, NewLIs);
+    normalizeSpillWeights(NewLIs);
     return NewLIs;
   }
 
@@ -1814,6 +1821,7 @@ addIntervalsForSpills(const LiveInterval &li,
   // Insert spills / restores if we are splitting.
   if (!TrySplit) {
     handleSpilledImpDefs(li, vrm, rc, NewLIs);
+    normalizeSpillWeights(NewLIs);
     return NewLIs;
   }
 
@@ -1973,6 +1981,7 @@ addIntervalsForSpills(const LiveInterval &li,
   }
 
   handleSpilledImpDefs(li, vrm, rc, RetNewLIs);
+  normalizeSpillWeights(RetNewLIs);
   return RetNewLIs;
 }
 
diff --git a/test/CodeGen/X86/2008-02-22-ReMatBug.ll b/test/CodeGen/X86/2008-02-22-ReMatBug.ll
index 8d6bb0df1f..a91ac27f98 100644
--- a/test/CodeGen/X86/2008-02-22-ReMatBug.ll
+++ b/test/CodeGen/X86/2008-02-22-ReMatBug.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=x86 -stats |& grep {Number of re-materialization} | grep 3
+; RUN: llc < %s -march=x86 -stats |& grep {Number of re-materialization} | grep 2
 ; rdar://5761454
 
 	%struct.quad_struct = type { i32, i32, %struct.quad_struct*, %struct.quad_struct*, %struct.quad_struct*, %struct.quad_struct*, %struct.quad_struct* }
diff --git a/test/CodeGen/X86/pr3495-2.ll b/test/CodeGen/X86/pr3495-2.ll
index 71aa5a0488..98c064a07d 100644
--- a/test/CodeGen/X86/pr3495-2.ll
+++ b/test/CodeGen/X86/pr3495-2.ll
@@ -1,4 +1,8 @@
-; RUN: llc < %s -march=x86 -relocation-model=pic -disable-fp-elim -stats |& grep {Number of reloads omited}
+; RUN: llc < %s -march=x86 -relocation-model=pic -disable-fp-elim -stats |& grep {Number of loads added} | grep 1
+; PR3495
+;
+; This test may not be testing what it was supposed to test.
+; It used to have two spills and four reloads, but not it only has one spill and one reload.
 
 target datalayout = "e-p:32:32:32"
 target triple = "i386-apple-darwin9.6"