collect2 does not handle static libraries to maybe_run_lto_and_relink so it doesn't get a chance to optimize using its content. This for example means that when bootstrapping with BOOT_CFLAGS=-flto libbackend.a does not benefit from lto.
-- Summary: collect2 (and maybe lto1) do not handle static libraries Product: gcc Version: lto Status: UNCONFIRMED Keywords: missed-optimization Severity: enhancement Priority: P3 Component: lto AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: rguenth at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41376