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by lionkor 1171 days ago
Respectfully, you would already be doing this in any C codebase, with `assert()`, right? We are all checking our preconditions with assert... right?
2 comments
GuB-42 1171 days ago
AFAIK, assert() is not undefined behavior, so it can't be used for optimization. It is either implementation-defined in debug mode, or does nothing in release mode.

For example:

  assert(a >= 0);
  if (a < 0) printf("a is negative");
In release mode, assert() will be gone, so the if/printf() will stay. If we used "if (a < 0) unreachable();" instead of assert(), it would optimize away both lines.
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pornel 1171 days ago
NDEBUG makes these checks disappear, so that's not an option for checks that are supposed to stay in the program.
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