Add test forgotten in r181388.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181389 91177308-0d34-0410-b5e6-96231b3b80d8

test/SemaCXX/constexpr-steps.cpp

@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -std=c++1y -fsyntax-only -verify %s -DMAX=1234 -fconstexpr-steps 1234
+// RUN: %clang_cc1 -std=c++1y -fsyntax-only -verify %s -DMAX=10 -fconstexpr-steps 10
+// RUN: %clang -std=c++1y -fsyntax-only -Xclang -verify %s -DMAX=12345 -fconstexpr-steps=12345
+
+// This takes a total of n + 4 steps according to our current rules:
+//  - One for the compound-statement that is the function body
+//  - One for the 'for' statement
+//  - One for the 'int k = 0;' statement
+//  - One for each of the n evaluations of the compound-statement in the 'for' body
+//  - One for the 'return' statemnet
+constexpr bool steps(int n) {
+  for (int k = 0; k != n; ++k) {}
+  return true; // expected-note {{step limit}}
+}
+
+static_assert(steps((MAX - 4)), ""); // ok
+static_assert(steps((MAX - 3)), ""); // expected-error {{constant}} expected-note{{call}}