* toplev.c (flag_asynchronous_unwind_tables): New global variable.
(lang_independent_options): Add asynchronous-unwind-tables
(toplev_main): flag_asynchronous_unwind_tables implies
flag_unwind_tables.
* flags.h (flag_asynchronous_unwind_tables): Declare.
* dwarf2out.c (dwarf2out_stack_adjust): Take into account
flag_asynchronous_unwind_tables.
(output_call_frame_info): Likewise.
* invoke.texi (-fasynchronous-unwind-tables): Document.
* i386.c (optimization_options): Enable
flag_asynchronous_unwind_tables.
* i386.c (ix86_expand_setcc): Always expect target to be QImode.
* i386.md (s* expanders): Destination is QImode.
* toplev.c (rest_of_compilation): Do not call clear_log_links.
* rtl.h (clear_log_links): Kill.
* flow.c (clear_log_links): Make static; accept blocks parameter;
do no clear life info.
(update_life_info): Call clear_log_links.