A linker issue causes code recompiled as part of link-time optimization to always use the "-O2" level of optimization. This means that when combined with -flto, code compiled with -O0 or -O1 may be faster, larger, and harder to debug. It also means that code compiled with -O3 may be significantly slower than expected when using link-time optimization.

As a workaround, affected programs may want to disable -flto entirely.

For performance-focused programs, excluding certain files from recompilation by not using -flto for those specific files may serve as an additional workaround.