http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55792
--- Comment #18 from Richard Biener <rguenth at gcc dot gnu.org> 2013-01-09 09:31:45 UTC --- (In reply to comment #17) > gimple_location is duplicated by: > > #1 0x0000000000751f32 in gimple_copy (stmt=0x7fffe8d75a00) > at /export/gnu/import/git/gcc/gcc/gimple.c:2205 > #2 0x00000000009c960d in gimple_duplicate_bb (bb=0x7fffe8d768f0) > at /export/gnu/import/git/gcc/gcc/tree-cfg.c:5397 > #3 0x00000000005b27a5 in duplicate_block (bb=0x7fffe8d768f0, > e=0x7fffe8d793f0, after=0x7fffe8d76888) > at /export/gnu/import/git/gcc/gcc/cfghooks.c:1012 > #4 0x000000000099c511 in tail_duplicate () > at /export/gnu/import/git/gcc/gcc/tracer.c:323 > #5 0x000000000099c765 in tracer () > at /export/gnu/import/git/gcc/gcc/tracer.c:380 > #6 0x00000000008ae0e6 in execute_one_pass (pass=0x16d18a0 <pass_tracer>) > at /export/gnu/import/git/gcc/gcc/passes.c:2335 > #7 0x00000000008ae2da in execute_pass_list (pass=0x16d18a0 <pass_tracer>) > at /export/gnu/import/git/gcc/gcc/passes.c:2383 > #8 0x00000000008ae30b in execute_pass_list ( > pass=0x16d07e0 <pass_all_optimizations>) > at /export/gnu/import/git/gcc/gcc/passes.c:2384 > #9 0x00000000005da366 in expand_function (node=0x7ffff17536f0) > at /export/gnu/import/git/gcc/gcc/cgraphunit.c:1641 > #10 0x00000000005da821 in expand_all_functions () > at /export/gnu/import/git/gcc/gcc/cgraphunit.c:1745 > (gdb) p copy > $176 = (gimple) 0x7fffe8e0a320 > (gdb) The BLOCK of the location is kept live by being referenced by the stmt copy (what kind is the stmt? the only stmt not well handled seems to be CLOBBERs) > Later, the original location is removed: > > #0 remove_unused_locals () > at /export/gnu/import/git/gcc/gcc/tree-ssa-live.c:793 > #1 0x00000000008ad5cb in execute_function_todo (data=0x8800) > at /export/gnu/import/git/gcc/gcc/passes.c:1952 > #2 0x00000000008ac965 in do_per_function ( > callback=0x8ad4ae <execute_function_todo(void*)>, data=0x8800) > at /export/gnu/import/git/gcc/gcc/passes.c:1703 > #3 0x00000000008ad765 in execute_todo (flags=34816) > at /export/gnu/import/git/gcc/gcc/passes.c:2001 > #4 0x00000000008ae175 in execute_one_pass ( > pass=0x16d3220 <pass_cleanup_cfg_post_optimizing>) > at /export/gnu/import/git/gcc/gcc/passes.c:2349 > #5 0x00000000008ae2da in execute_pass_list ( > pass=0x16d3220 <pass_cleanup_cfg_post_optimizing>) > at /export/gnu/import/git/gcc/gcc/passes.c:2383 > #6 0x00000000005da366 in expand_function (node=0x7ffff17536f0) > at /export/gnu/import/git/gcc/gcc/cgraphunit.c:1641 > #7 0x00000000005da821 in expand_all_functions () > at /export/gnu/import/git/gcc/gcc/cgraphunit.c:1745 > > and freed. You probably mean BLOCK - it should be still live as referenced from the stmt, or cleaned from the stmt if it was a debug stmt. > Then we copy the freed gimple_location: > > #0 expand_gimple_stmt_1 (stmt=0x7fffe8e0a320) > at /export/gnu/import/git/gcc/gcc/cfgexpand.c:2202 > #1 0x00000000005a7786 in expand_gimple_stmt (stmt=0x7fffe8e0a320) > at /export/gnu/import/git/gcc/gcc/cfgexpand.c:2305 > #2 0x00000000005ad975 in expand_gimple_basic_block (bb=0x7fffe8d76888, > disable_tail_calls=false) > at /export/gnu/import/git/gcc/gcc/cfgexpand.c:4084 > #3 0x00000000005af426 in gimple_expand_cfg () > at /export/gnu/import/git/gcc/gcc/cfgexpand.c:4603 > #4 0x00000000008ae0e6 in execute_one_pass (pass=0x16ce300 <pass_expand>) > at /export/gnu/import/git/gcc/gcc/passes.c:2335 > #5 0x00000000008ae2da in execute_pass_list (pass=0x16ce300 <pass_expand>) > at /export/gnu/import/git/gcc/gcc/passes.c:2383 > #6 0x00000000005da366 in expand_function (node=0x7ffff17536f0) > at /export/gnu/import/git/gcc/gcc/cgraphunit.c:1641 > #7 0x00000000005da821 in expand_all_functions () > at /export/gnu/import/git/gcc/gcc/cgraphunit.c:1745 > #8 0x00000000005db2ab in compile () > at /export/gnu/import/git/gcc/gcc/cgraphunit.c:2043 > #9 0x000000000053c60a in lto_main () > at /export/gnu/import/git/gcc/gcc/lto/lto.c:3390 > #10 0x0000000000999401 in compile_file () > at /export/gnu/import/git/gcc/gcc/toplev.c:545
