[clang][CoverageMapping] do not emit gap when either end is an ImplicitValueInitExpr

Author: whentojump

clang/lib/CodeGen/CoverageMappingGen.cpp

@@ -1368,9 +1368,12 @@ struct CounterCoverageMappingBuilder
     for (const Stmt *Child : S->children())
       if (Child) {
         // If last statement contains terminate statements, add a gap area
-        // between the two statements. Skipping attributed statements, because
-        // they don't have valid start location.
-        if (LastStmt && HasTerminateStmt && !isa<AttributedStmt>(Child)) {
+        // between the two statements. Skipping attributed statements and
+        // implicit initializations, because they don't have valid source
+        // location.
+        if (LastStmt && HasTerminateStmt && !isa<AttributedStmt>(Child) &&
+            !isa<ImplicitValueInitExpr>(Child) &&
+            !isa<ImplicitValueInitExpr>(LastStmt)) {
           auto Gap = findGapAreaBetween(getEnd(LastStmt), getStart(Child));
           if (Gap)
             fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(),