[block-freq] Teach branch probability how to return the edge weight in between a BasicBlock and one of its successors.

IMHO At some point BasicBlock should be refactored along the lines of
MachineBasicBlock so that successors/weights are actually embedded within the
block. Now is not that time though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197303 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/BranchProbabilityInfo.h

@@ -16,6 +16,7 @@
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Support/CFG.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/BranchProbability.h"
@@ -98,6 +99,9 @@ public:
   /// It is guaranteed to fall between 1 and UINT32_MAX.
   uint32_t getEdgeWeight(const BasicBlock *Src, const BasicBlock *Dst) const;
 
+  uint32_t getEdgeWeight(const BasicBlock *Src,
+                         succ_const_iterator Dst) const;
+
   /// \brief Set the raw edge weight for a given edge.
   ///
   /// This allows a pass to explicitly set the edge weight for an edge. It can