Revert r254348: "Replace all weight-based interfaces in MBB with probability-based interfaces, and update all uses of old interfaces."

and the follow-up r254356: "Fix a bug in MachineBlockPlacement that may cause assertion failure during BranchProbability construction."

Asserts were firing in Chromium builds. See PR25687.

llvm-svn: 254366
diff --git a/llvm/lib/CodeGen/TailDuplication.cpp b/llvm/lib/CodeGen/TailDuplication.cpp
index 1f5b548..ff86dab 100644
--- a/llvm/lib/CodeGen/TailDuplication.cpp
+++ b/llvm/lib/CodeGen/TailDuplication.cpp
@@ -745,12 +745,12 @@
     if (PredTBB)
       TII->InsertBranch(*PredBB, PredTBB, PredFBB, PredCond, DebugLoc());
 
-    auto Prob = MBPI->getEdgeProbability(PredBB, TailBB);
+    uint32_t Weight = MBPI->getEdgeWeight(PredBB, TailBB);
     PredBB->removeSuccessor(TailBB);
     unsigned NumSuccessors = PredBB->succ_size();
     assert(NumSuccessors <= 1);
     if (NumSuccessors == 0 || *PredBB->succ_begin() != NewTarget)
-      PredBB->addSuccessor(NewTarget, Prob);
+      PredBB->addSuccessor(NewTarget, Weight);
 
     TDBBs.push_back(PredBB);
   }
@@ -858,7 +858,7 @@
            "TailDuplicate called on block with multiple successors!");
     for (MachineBasicBlock::succ_iterator I = TailBB->succ_begin(),
            E = TailBB->succ_end(); I != E; ++I)
-      PredBB->addSuccessor(*I, MBPI->getEdgeProbability(TailBB, I));
+      PredBB->addSuccessor(*I, MBPI->getEdgeWeight(TailBB, I));
 
     Changed = true;
     ++NumTailDups;