A call to strlen is not a constant expression, even if we're treating it as a

builtin.

llvm-svn: 148374

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/constexpr-strlen.cpp b/clang/test/SemaCXX/constexpr-strlen.cpp
new file mode 100644
index 00000000000..5e28e7f0ce5
--- /dev/null
+++ b/clang/test/SemaCXX/constexpr-strlen.cpp
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 %s -std=c++11 -fsyntax-only -verify -pedantic
+
+# 1 "/usr/include/string.h" 1 3 4
+extern "C" {
+  typedef decltype(sizeof(int)) size_t;
+  extern size_t strlen(const char *p);
+}
+
+# 10 "SemaCXX/constexpr-strlen.cpp" 2
+constexpr int n = __builtin_strlen("hello"); // ok
+constexpr int m = strlen("hello"); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strlen' cannot be used in a constant expression}}
+
+// Make sure we can evaluate a call to strlen.
+int arr[3]; // expected-note {{here}}
+int k = arr[strlen("hello")]; // expected-warning {{array index 5}}