[llvm] [BOLT] Allow pass-through blocks in YAMLProfileReader (PR #91828)

[Alexander Yermolovich via llvm-commits]

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@@ -218,17 +218,29 @@ bool YAMLProfileReader::parseFunctionProfile(
         continue;
       }
 
-      BinaryBasicBlock &SuccessorBB = *Order[YamlSI.Index];
-      if (!BB.getSuccessor(SuccessorBB.getLabel())) {
-        if (opts::Verbosity >= 1)
-          errs() << "BOLT-WARNING: no successor for block " << BB.getName()
-                 << " that matches index " << YamlSI.Index << " or block "
-                 << SuccessorBB.getName() << '\n';
-        ++MismatchedEdges;
-        continue;
+      BinaryBasicBlock *ToBB = Order[YamlSI.Index];
+      if (!BB.getSuccessor(ToBB->getLabel())) {
+        // Allow for BOLT-removed passthrough blocks to align with DataReader
+        // behavior.
+        BinaryBasicBlock *FTSuccessor = BB.getConditionalSuccessor(false);
+        if (FTSuccessor && FTSuccessor->succ_size() == 1 &&
+            FTSuccessor->getSuccessor(ToBB->getLabel())) {
+          BinaryBasicBlock::BinaryBranchInfo &FTBI =
+              FTSuccessor->getBranchInfo(*ToBB);
+          FTBI.Count += YamlSI.Count;
+          FTBI.MispredictedCount += YamlSI.Mispreds;
+          ToBB = FTSuccessor;
+        } else {
+          if (opts::Verbosity >= 1)
+            errs() << "BOLT-WARNING: no successor for block " << BB.getName()
----------------
ayermolo wrote:

Thought we know using BC for logging?

https://github.com/llvm/llvm-project/pull/91828