[llvm] [Analysis][NFC] Use block numbers for BranchProbabilityInfo (PR #186658)

[Alexis Engelke via llvm-commits]

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@@ -1387,31 +1405,25 @@ void BranchProbabilityInfo::setEdgeProbability(
 
 void BranchProbabilityInfo::copyEdgeProbabilities(BasicBlock *Src,
                                                   BasicBlock *Dst) {
-  eraseBlock(Dst); // Erase stale data if any.
-  unsigned NumSuccessors = Src->getTerminator()->getNumSuccessors();
-  assert(NumSuccessors == Dst->getTerminator()->getNumSuccessors());
-  if (NumSuccessors == 0)
-    return; // Nothing to set.
-  if (!this->Probs.contains(std::make_pair(Src, 0)))
-    return; // No probability is set for edges from Src. Keep the same for Dst.
-
-  Handles.insert(BasicBlockCallbackVH(Dst, this));
-  for (unsigned SuccIdx = 0; SuccIdx < NumSuccessors; ++SuccIdx) {
-    auto Prob = this->Probs[std::make_pair(Src, SuccIdx)];
-    this->Probs[std::make_pair(Dst, SuccIdx)] = Prob;
-    LLVM_DEBUG(dbgs() << "set edge " << Dst->getName() << " -> " << SuccIdx
-                      << " successor probability to " << Prob << "\n");
+  assert(succ_size(Src) == succ_size(Dst));
+  // allocEdges can reallocate and must be called first.
+  MutableArrayRef<BranchProbability> DstP = allocEdges(Dst);
+  const BranchProbability *SrcP = getEdges(Src);
+  if (!SrcP) {
+    eraseBlock(Dst);
+    return;
+  }
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aengelke wrote:

Actually no: if !SrcP, it might also be the case that we don't have info for Src.

https://github.com/llvm/llvm-project/pull/186658