clang/test/SemaCXX/constexpr-steps.cpp

   1 // RUN: %clang_cc1 -std=c++1y -fsyntax-only -verify %s -DMAX=1234 -fconstexpr-steps 1234
   2 // RUN: %clang_cc1 -std=c++1y -fsyntax-only -verify %s -DMAX=10 -fconstexpr-steps 10
   3 // RUN: %clang -std=c++1y -fsyntax-only -Xclang -verify %s -DMAX=12345 -fconstexpr-steps=12345
   4
   5 // This takes a total of n + 4 steps according to our current rules:
   6 //  - One for the compound-statement that is the function body
   7 //  - One for the 'for' statement
   8 //  - One for the 'int k = 0;' statement
   9 //  - One for each of the n evaluations of the compound-statement in the 'for' body
  10 //  - One for the 'return' statemnet
  11 constexpr bool steps(int n) {
  12   for (int k = 0; k != n; ++k) {}
  13   return true; // expected-note {{step limit}}
  14 }
  15
  16 static_assert(steps((MAX - 4)), ""); // ok
  17 static_assert(steps((MAX - 3)), ""); // expected-error {{constant}} expected-note{{call}}