Change the table datastructure to be a vector<smallvector>, instead of

vector<vector> to avoid allocations.  This speeds up bcwriting of 447.dealII
from 0.8276 to 0.7637s (8.4%).

This concludes this round of proding the bcwriter into submission.  Final
speedup from 24.4s to 0.7637s (32x).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34142 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bytecode/Writer/SlotCalculator.h

@@ -21,6 +21,7 @@
 #define LLVM_ANALYSIS_SLOTCALCULATOR_H
 
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
 #include <vector>
 
 namespace llvm {
@@ -44,9 +45,10 @@ struct ModuleLevelDenseMapKeyInfo {
 
 class SlotCalculator {
   const Module *TheModule;
-
+public:
   typedef std::vector<const Type*> TypeList;
-  typedef std::vector<const Value*> TypePlane;
+  typedef SmallVector<const Value*, 16> TypePlane;
+private:
   std::vector<TypePlane> Table;
   TypeList Types;
   typedef DenseMap<const Value*, unsigned> NodeMapType;