Add driver arguments -ftemplate-depth=N and -fconstexpr-depth=N, with the same

semantics and defaults as the corresponding g++ arguments. The historical g++
argument -ftemplate-depth-N is kept for compatibility, but modern g++ versions
no longer document that option.

Add -cc1 argument -fconstexpr-depth N to implement the corresponding
functionality.

The -ftemplate-depth=N part of this fixes PR9890.

llvm-svn: 145045

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/constexpr-depth.cpp b/clang/test/SemaCXX/constexpr-depth.cpp
new file mode 100644
index 00000000000..b8ae6682c56
--- /dev/null
+++ b/clang/test/SemaCXX/constexpr-depth.cpp
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s -DMAX=128 -fconstexpr-depth 128
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s -DMAX=1 -fconstexpr-depth 1
+// RUN: %clang -std=c++11 -fsyntax-only -Xclang -verify %s -DMAX=10 -fconstexpr-depth=10
+
+constexpr int depth(int n) { return n > 1 ? depth(n-1) : 0; }
+
+constexpr int kBad = depth(MAX + 1); // expected-error {{must be initialized by a constant expression}}
+constexpr int kGood = depth(MAX);