[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.

llvm-svn: 197303
diff --git a/llvm/lib/Analysis/BranchProbabilityInfo.cpp b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
index 86560ca..15491f0 100644
--- a/llvm/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#define DEBUG_TYPE "branch-prob"
 #include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/Analysis/LoopInfo.h"
@@ -483,6 +484,8 @@
 }
 
 bool BranchProbabilityInfo::runOnFunction(Function &F) {
+  DEBUG(dbgs() << "---- Branch Probability Info : " << F.getName()
+               << " ----\n\n");
   LastF = &F; // Store the last function we ran on for printing.
   LI = &getAnalysis<LoopInfo>();
   assert(PostDominatedByUnreachable.empty());
@@ -591,6 +594,13 @@
   return DEFAULT_WEIGHT;
 }
 
+uint32_t
+BranchProbabilityInfo::
+getEdgeWeight(const BasicBlock *Src, succ_const_iterator Dst) const {
+  size_t index = std::distance(succ_begin(Src), Dst);
+  return getEdgeWeight(Src, index);
+}
+
 /// Get the raw edge weight calculated for the block pair. This returns the sum
 /// of all raw edge weights from Src to Dst.
 uint32_t BranchProbabilityInfo::