https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87883
--- Comment #2 from Jozef Lawrynowicz <jozef.l at mittosystems dot com> --- Created attachment 45074 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45074&action=edit reg class checking patch Hi Mihail, Thanks for the info. I fixed a bug for msp430-elf caused by REGNO_REG_CLASS and REG_CLASS_CONTENTS being out of sync i.e. REGNO_REG_CLASS[reg] reported one class, but the bit for that reg in that class was not set in REG_CLASS_CONTENTS. So I was trying to add some generic warning to the middle-end which would catch these cases for other targets (see attached patch). However, there were some other issues with my proposal so I've parked it for now. Given that I'm not going to proceed with my patch in its current state, it's up to you whether to close this PR or not. Kind regards, Jozef