[libcxx-commits] [PATCH] D118940: [libc++] Fix std::__debug_less in c++17.

Thu Feb 3 15:51:37 PST 2022

philnik added a comment.

In D118940#3295347 <https://reviews.llvm.org/D118940#3295347>, @Quuxplusone wrote:

> The patch looks good to me now... but we //do// have a buildkite runner that runs in Debug mode, and it didn't catch the thing you originally mentioned.
> Can someone explain why `libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_init_list_comp.pass.cpp` does not detect the problem?  I paste it into Godbolt and it detects the problem: https://godbolt.org/z/eKvcvbb7d yet the "Debug mode" buildkite job isn't failing.
>
> ...Ooh. It's because the "Debug mode" buildkite job uses only C++20 or C++2b, isn't it? The combinatorial explosion of config options strikes again. :(  @ldionne @philnik any thoughts on how to improve our CI coverage here?

Yeah, exponential growth really sucks. A few things I thought of:
(1) Have an infinite amount of money to throw at CI. That would mean we have 0 bugs, but it //might// not be feasible.
(2) Ignore it and hope for the best
(3) It would still be expensive, but we could see how expensive it is to only compile all the tests, and therefore effectively only testing `constexpr` with debug
(4) Remove some configurations

I guess option 3 would be the best option, but it might be too costly. So it's most likely going to be option 2.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D118940/new/

https://reviews.llvm.org/D118940