3 files changed, 10 insertions, 5 deletions
diff --git a/llvm/lib/Fuzzer/FuzzerInternal.h b/llvm/lib/Fuzzer/FuzzerInternal.h
index d9dc5283689..c44f0ea34d5 100644
--- a/llvm/lib/Fuzzer/FuzzerInternal.h
+++ b/llvm/lib/Fuzzer/FuzzerInternal.h
@@ -53,6 +53,7 @@ void ComputeSHA1(const uint8_t *Data, size_t Len, uint8_t *Out);
 // Changes U to contain only ASCII (isprint+isspace) characters.
 // Returns true iff U has been changed.
 bool ToASCII(Unit &U);
+bool IsASCII(const Unit &U);
 
 int NumberOfCpuCores();
 
diff --git a/llvm/lib/Fuzzer/FuzzerLoop.cpp b/llvm/lib/Fuzzer/FuzzerLoop.cpp
index 87ba0c0bbcd..dd81616b455 100644
--- a/llvm/lib/Fuzzer/FuzzerLoop.cpp
+++ b/llvm/lib/Fuzzer/FuzzerLoop.cpp
@@ -136,6 +136,8 @@ void Fuzzer::ShuffleAndMinimize() {
       U.clear();
       size_t Last = std::min(First + Options.MaxLen, C.size());
       U.insert(U.begin(), C.begin() + First, C.begin() + Last);
+      if (Options.OnlyASCII)
+        ToASCII(U);
       size_t NewCoverage = RunOne(U);
       if (NewCoverage) {
         MaxCov = NewCoverage;
@@ -256,11 +258,7 @@ void Fuzzer::WriteToOutputCorpus(const Unit &U) {
   WriteToFile(U, Path);
   if (Options.Verbosity >= 2)
     Printf("Written to %s\n", Path.c_str());
-#ifdef DEBUG
-  if (Options.OnlyASCII)
-    for (auto X : U)
-      assert(isprint(X) || isspace(X));
-#endif
+  assert(!Options.OnlyASCII || IsASCII(U));
 }
 
 void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
diff --git a/llvm/lib/Fuzzer/FuzzerUtil.cpp b/llvm/lib/Fuzzer/FuzzerUtil.cpp
index e76adb37481..b04d76d316d 100644
--- a/llvm/lib/Fuzzer/FuzzerUtil.cpp
+++ b/llvm/lib/Fuzzer/FuzzerUtil.cpp
@@ -86,4 +86,10 @@ bool ToASCII(Unit &U) {
   return Changed;
 }
 
+bool IsASCII(const Unit &U) {
+  for (auto X : U)
+    if (!(isprint(X) || isspace(X))) return false;
+  return true;
+}
+
 }  // namespace fuzzer