https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85211
--- Comment #7 from blastrock at free dot fr --- You are right, my bad. I managed to build it by adding the definition in gcc/config/arm/arm.h . My initial suggestion was to mention that behavior in the documentation, but if you think it is not worth it, I guess you can close this bug. Thanks anyway for your help!