Correct behavior of __builtin_*_overflow and constexpr.

Enable these builtins to be called across a lambda
boundary with captureless const/constexpr, as brought up by 
Eli here: https://reviews.llvm.org/D48040

Differential Revision: https://reviews.llvm.org/D48053

llvm-svn: 334597

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/builtins-overflow.cpp b/clang/test/SemaCXX/builtins-overflow.cpp
new file mode 100644
index 00000000000..9054cce2573
--- /dev/null
+++ b/clang/test/SemaCXX/builtins-overflow.cpp
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify %s
+// expected-no-diagnostics
+
+int a() {
+  const int x = 3;
+  static int z;
+  constexpr int *y = &z;
+  return []() { return __builtin_sub_overflow((int)x, (int)x, (int *)y); }();
+}
+int a2() {
+  const int x = 3;
+  static int z;
+  constexpr int *y = &z;
+  return []() { return __builtin_sub_overflow(x, x, y); }();
+}