[clang] [llvm] [MC/DC][Coverage] Loosen the limit of NumConds from 6 (PR #82448)

[Hana Dusíková via cfe-commits]

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@@ -223,9 +223,130 @@ Expected<int64_t> CounterMappingContext::evaluate(const Counter &C) const {
   return LastPoppedValue;
 }
 
+mcdc::TVIdxBuilder::TVIdxBuilder(const SmallVectorImpl<ConditionIDs> &NextIDs,
+                                 int Offset)
+    : Indices(NextIDs.size()) {
+  // Construct Nodes and set up each InCount
+  auto N = NextIDs.size();
+  SmallVector<MCDCNode> Nodes(N);
+  for (unsigned ID = 0; ID < N; ++ID) {
+    for (unsigned C = 0; C < 2; ++C) {
+#ifndef NDEBUG
+      Indices[ID][C] = INT_MIN;
+#endif
+      auto NextID = NextIDs[ID][C];
+      Nodes[ID].NextIDs[C] = NextID;
+      if (NextID >= 0)
+        ++Nodes[NextID].InCount;
+    }
+  }
+
+  // Sort key ordered by <-Width, Ord>
+  SmallVector<std::tuple<int,      /// -Width
+                         unsigned, /// Ord
+                         int,      /// ID
+                         unsigned  /// Cond (0 or 1)
+                         >>
+      Decisions;
+
+  // Traverse Nodes to assign Idx
+  SmallVector<int> Q;
+  assert(Nodes[0].InCount == 0);
+  Nodes[0].Width = 1;
+  Q.push_back(0);
+
+  unsigned Ord = 0;
+  while (!Q.empty()) {
+    auto IID = Q.begin();
+    int ID = *IID;
+    Q.erase(IID);
+    auto &Node = Nodes[ID];
+    assert(Node.Width > 0);
+
+    for (unsigned I = 0; I < 2; ++I) {
+      auto NextID = Node.NextIDs[I];
+      assert(NextID != 0 && "NextID should not point to the top");
+      if (NextID < 0) {
+        // Decision
+        Decisions.emplace_back(-Node.Width, Ord++, ID, I);
+        assert(Ord == Decisions.size());
+        continue;
+      }
+
+      // Inter Node
+      auto &NextNode = Nodes[NextID];
+      assert(NextNode.InCount > 0);
+
+      // Assign Idx
+      assert(Indices[ID][I] == INT_MIN);
+      Indices[ID][I] = NextNode.Width;
+      auto NextWidth = int64_t(NextNode.Width) + Node.Width;
+      if (NextWidth > HardMaxTVs) {
+        NumTestVectors = HardMaxTVs; // Overflow
+        return;
+      }
+      NextNode.Width = NextWidth;
+
+      // Ready if all incomings are processed.
+      // Or NextNode.Width hasn't been confirmed yet.
+      if (--NextNode.InCount == 0)
+        Q.push_back(NextID);
+    }
+  }
+
+  std::sort(Decisions.begin(), Decisions.end());
+
+  // Assign TestVector Indices in Decision Nodes
+  int64_t CurIdx = 0;
+  for (auto [NegWidth, Ord, ID, C] : Decisions) {
+    int Width = -NegWidth;
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hanickadot wrote:

change it also here if you change Decision to a smallvector of defined struct 

https://github.com/llvm/llvm-project/pull/82448