https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103202
--- Comment #6 from Aldy Hernandez <aldyh at gcc dot gnu.org> --- Not looking at this yet, but disabling jump threading from all passes (dom included) makes the problem go away: $ ./xgcc -B./ a.c -w -O2 -fno-thread-jumps && ./a.out element 1 element 2 element 3 ...so *maybe* threading related. The minimum number of threads that reproduces this is: ./xgcc -B./ a.c -w -O2 -fdbg-cnt=registered_jump_thread:1-1:3-3:5-5 && ./a.out ***dbgcnt: lower limit 1 reached for registered_jump_thread.*** ***dbgcnt: upper limit 1 reached for registered_jump_thread.*** ***dbgcnt: lower limit 3 reached for registered_jump_thread.*** ***dbgcnt: upper limit 3 reached for registered_jump_thread.*** ***dbgcnt: lower limit 5 reached for registered_jump_thread.*** ***dbgcnt: upper limit 5 reached for registered_jump_thread.*** element 1 element 2 $ grep 'Register.*jump' a.c.* a.c.111t.threadfull1: [1] Registering jump thread: (6, 7) incoming edge; (7, 9) nocopy; a.c.126t.thread1: [3] Registering jump thread: (2, 4) incoming edge; (4, 12) nocopy; a.c.191t.thread2: [5] Registering jump thread: (13, 11) incoming edge; (11, 10) nocopy;
