https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63718
--- Comment #7 from vries at gcc dot gnu.org --- (In reply to Joey Ye from comment #6) > (In reply to vries from comment #5) > > Could you try out the patch and see if it fixes things for you? > > > Tom, thanks for the quick action. Apparantly this patch should recover the > bootstrap. I will test it and come back to you (bootstraping thumb1 with > qemu takes hours!) > Great :) > However, I think the fix is too conservative. There are plenty of chances > that r0-r3 will not be clobbered by return. For example armv6-m will pretty > much never uses r0-r3 implicitly. Indeed, the patch is conservative, but that's not such a bad idea for a correctness fix. We can always folllow up with a more optimal patch.