https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126123
--- Comment #1 from Avinash Jayakar <avinashd at gcc dot gnu.org> --- Hi, based on the ISA reference the lwarx takes 4 parameters, lwarx RT,RA,RB,EH the last one EH (exclusive hint) bit hints the core whether the stwcx accompanying this lwarx will be immediately be done by the same thread, so as to minimize the coherence traffic. I think this has been there from the beginning. lwarx RT, RA, RB is just an extended mnemonic for lwarx, with EH bit as 0. I think the Darwin's assembler has to be updated to recognize the EH parameter.
