diff --git a/llvm/tools/sancov/sancov.cpp b/llvm/tools/sancov/sancov.cpp
--- a/llvm/tools/sancov/sancov.cpp
+++ b/llvm/tools/sancov/sancov.cpp
@@ -131,8 +131,12 @@
 // Contents of .sancov file: list of coverage point addresses that were
 // executed.
 struct RawCoverage {
-  explicit RawCoverage(std::unique_ptr<std::set<uint64_t>> Addrs)
-      : Addrs(std::move(Addrs)) {}
+  explicit RawCoverage(std::unique_ptr<std::set<uint64_t>> RawAddrs)
+      : Addrs(std::move(RawAddrs)) {
+    // Ignore slots that are zero, so a runtime implementation is not required
+    // to compactify the data.
+    Addrs->erase(0);
+  }
 
   // Read binary .sancov file.
   static ErrorOr<std::unique_ptr<RawCoverage>>
@@ -1231,7 +1235,7 @@
   llvm::InitializeAllTargetMCs();
   llvm::InitializeAllDisassemblers();
 
-  cl::ParseCommandLineOptions(Argc, Argv, 
+  cl::ParseCommandLineOptions(Argc, Argv,
       "Sanitizer Coverage Processing Tool (sancov)\n\n"
       "  This tool can extract various coverage-related information from: \n"
       "  coverage-instrumented binary files, raw .sancov files and their "