http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52172
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-02-13 20:26:58 UTC --- Created attachment 26654 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26654 vartrack.ii Slightly reduced testcase. Reproduceable with ./g++ -B ./ -S -fcompare-debug -g -O2 -fno-exceptions -fno-rtti -pedantic -fno-common vartrack.ii --param min-nondebug-insn-uid=10000 (the param in order to make the debugging at least bearable by making the uids match for non-debug insns). The problem seems to be in remove_useless_values happening at different times during sched2 (part of ia64 mach pass). There we for a DEBUG_INSN insn do first cselib_lookup_from_insn (... , insn), then call cselib_subst_to_values. Unfortunately the latter means cselib_current_insn is NULL and promote_debug_loc decides to promote it (and clear setting_insn) even for a debug stmt value that -g0 compilation doesn't touch in any way.
