Compilers typically don't use multiple cores, but the build system that invokes them do, by invoking them in parallel. Modern build systems will typically invoke commands for 1 target per core, which means that on my system for example, building my software uses all 16 cores more or less until the final steps of the process.

The speed record for building my software is held by a system with over 1k cores (a couple of seconds, compared to multiple minutes on a mid-size Threadripper).

I can stress out a 32+32 core 2990WX with 'make -j' on some of my projects, htop essentially has every core pegged.

Just running the tests in our Rails project (11k of them) can stress out a ton; we're regularly running it on 80+ cores to keep our test completion time ~3 minutes. M1 Max should let me run all tests locally much faster than I can today.

Wow, what is the system doing to have 11000 tests?

Rust (Cargo) does, and always wants more.

Often a single compiler won't make use of more than a core, but it's generally easy to build independent modules in parallel.

For example, make -j 10, or mvn -T 10.

Xcode has no issues taking advantage of all cores.

C++ compilers probably will.