https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81861
--- Comment #6 from Maxim Ostapenko <m.ostapenko at samsung dot com> --- Created attachment 41990 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41990&action=edit Untested fix The problem is that LTO doesn't propagate changed ix86_stack_protector_guard_reg value: 6654 /* Save the initial options in case the user does function specific 6655 options. */ 6656 if (main_args_p) 6657 target_option_default_node = target_option_current_node 6658 = build_target_option_node (opts); <== save flags 6659 ... 6695 ix86_stack_protector_guard_reg = DEFAULT_TLS_SEG_REG; <== missed change Thus ix86_stack_protector_guard_reg becomes left ADDR_SPACE_GENERIC in ltrans stage that confuses optimizer later (wrong constant propagation in this case). Moving options saving down fixes the issue, although I'm not sure this is a correct fix.
