[block-freq] Add the APInt method extractBit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197271 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/APInt.h

@@ -1244,6 +1244,9 @@ public:
   /// as "bitPosition".
   void flipBit(unsigned bitPosition);
 
+  /// \brief Returns true if the bit in bitPosition is set.
+  bool extractBit(unsigned bitPosition) const;
+
   /// @}
   /// \name Value Characterization Functions
   /// @{