diff --git a/test/tools/llvm-strings/negative-char.test b/test/tools/llvm-strings/negative-char.test
new file mode 100644
index 00000000000..331dde47078
--- /dev/null
+++ b/test/tools/llvm-strings/negative-char.test
@@ -0,0 +1,3 @@
+# RUN: echo -e "z\0\x80\0a\0" | llvm-strings --bytes 1 - | FileCheck %s
+# CHECK: z{{$}}
+# CHECK-NEXT: {{^}} a
diff --git a/tools/llvm-strings/llvm-strings.cpp b/tools/llvm-strings/llvm-strings.cpp
index 8e2d213bcc7..c355caf899d 100644
--- a/tools/llvm-strings/llvm-strings.cpp
+++ b/tools/llvm-strings/llvm-strings.cpp
@@ -80,7 +80,7 @@ static void strings(raw_ostream &OS, StringRef FileName, StringRef Contents) {
   const char *B = Contents.begin();
   const char *P = nullptr, *E = nullptr, *S = nullptr;
   for (P = Contents.begin(), E = Contents.end(); P < E; ++P) {
-    if (std::isgraph(*P) || std::isblank(*P)) {
+    if (isPrint(*P) || *P == '\t') {
       if (S == nullptr)
         S = P;
     } else if (S) {