[llvm] [Coverage] Rework Decision/Expansion/Branch (PR #78969)

[NAKAMURA Takumi via llvm-commits]

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@@ -662,23 +724,39 @@ Error CoverageMapping::loadFunctionRecord(
     }
     Function.pushRegion(Region, *ExecutionCount, *AltExecutionCount);
 
+    if (Region.Kind == CounterMappingRegion::ExpansionRegion) {
+      for (auto &Decision : reverse(Decisions)) {
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chapuni wrote:

I have rewritten whole things in `DecisionRow`.

https://github.com/llvm/llvm-project/pull/78969