Merge branch 'users/chapuni/cov/single/getpair' into users/chapuni/cov/single/nextcount-base

Author: chapuni

clang/lib/CodeGen/CoverageMappingGen.cpp

@@ -944,9 +944,18 @@ struct CounterCoverageMappingBuilder
     return {ExecCnt, Builder.subtract(ParentCnt, ExecCnt)};
   }
 
-  Counter getSwitchImplicitDefaultCounter(const Stmt *Cond, Counter ParentCount,
-                                          Counter CaseCountSum) {
-    return Builder.subtract(ParentCount, CaseCountSum);
+  /// Returns {TrueCnt,FalseCnt} for "implicit default".
+  /// FalseCnt is considered as the False count on SwitchStmt.
+  std::pair<Counter, Counter>
+  getSwitchImplicitDefaultCounterPair(const Stmt *Cond, Counter ParentCount,
+                                      Counter CaseCountSum) {
+    // Simplify is skipped while building the counters above: it can get
+    // really slow on top of switches with thousands of cases. Instead,
+    // trigger simplification by adding zero to the last counter.
+    CaseCountSum =
+        addCounters(CaseCountSum, Counter::getZero(), /*Simplify=*/true);
+
+    return {CaseCountSum, Builder.subtract(ParentCount, CaseCountSum)};
   }
 
   bool IsCounterEqual(Counter OutCount, Counter ParentCount) {
@@ -1907,15 +1916,9 @@ struct CounterCoverageMappingBuilder
     // the hidden branch, which will be added later by the CodeGen. This region
     // will be associated with the switch statement's condition.
     if (!HasDefaultCase) {
-      // Simplify is skipped while building the counters above: it can get
-      // really slow on top of switches with thousands of cases. Instead,
-      // trigger simplification by adding zero to the last counter.
-      CaseCountSum =
-          addCounters(CaseCountSum, Counter::getZero(), /*Simplify=*/true);
-
-      // This is considered as the False count on SwitchStmt.
-      Counter SwitchFalse = subtractCounters(ParentCount, CaseCountSum);
-      createBranchRegion(S->getCond(), CaseCountSum, SwitchFalse);
+      auto Counters = getSwitchImplicitDefaultCounterPair(
+          S->getCond(), ParentCount, CaseCountSum);
+      createBranchRegion(S->getCond(), Counters.first, Counters.second);
     }
   }