2 files changed, 32 insertions, 0 deletions
diff --git a/test/fuzzer/ImplicitIntegerTruncationTest.cpp b/test/fuzzer/ImplicitIntegerTruncationTest.cpp
new file mode 100644
index 0000000000000..cb935da0c13e3
--- /dev/null
+++ b/test/fuzzer/ImplicitIntegerTruncationTest.cpp
@@ -0,0 +1,27 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test for signed-integer-overflow.
+#include <assert.h>
+#include <climits>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+
+static volatile int Sink;
+static unsigned char Large = UINT8_MAX;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  if (Size > 0 && Data[0] == 'H') {
+    Sink = 1;
+    if (Size > 1 && Data[1] == 'i') {
+      Sink = 2;
+      if (Size > 2 && Data[2] == '!') {
+        Large = Large + 1;  // 'char overflow'.
+      }
+    }
+  }
+  return 0;
+}
diff --git a/test/fuzzer/fuzzer-implicit-integer-truncation.test b/test/fuzzer/fuzzer-implicit-integer-truncation.test
new file mode 100644
index 0000000000000..212559bdca3c4
--- /dev/null
+++ b/test/fuzzer/fuzzer-implicit-integer-truncation.test
@@ -0,0 +1,5 @@
+RUN: rm -f %t-ImplicitIntegerTruncationTest-Ubsan
+RUN: %cpp_compiler -fsanitize=implicit-integer-truncation -fno-sanitize-recover=all %S/ImplicitIntegerTruncationTest.cpp -o %t-ImplicitIntegerTruncationTest-Ubsan
+RUN: not %run %t-ImplicitIntegerTruncationTest-Ubsan 2>&1 | FileCheck %s
+CHECK: runtime error: implicit conversion from type 'int' of value 256 (32-bit, signed) to type 'unsigned char' changed the value to 0 (8-bit, unsigned)
+CHECK: Test unit written to ./crash-