https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106531
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Waterman from comment #1) > It turns out there is no such thing as the B extension; it was a working > name for a draft proposal a few years ago but wasn't (and presumably won't > be) ratified. The correct behavior is to reject B but accept zba, zbb, zbc, > and zbs. -march=rv32imac_zba_zbb_zbc_zbs works but that is just so bad. Really b should just mean all 4 really; it should be a meta ISA extension :). There is so much no documentation on what ISA names; that I had to just guess.
