[Bug other/55358] Valgrind errors

[markus at trippelsdorf dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55358



--- Comment #7 from Markus Trippelsdorf <markus at trippelsdorf dot de> 
2012-11-28 13:20:54 UTC ---

The fix for:

==23637== Invalid write of size 8

==23637==    at 0xCF9951: rest_of_handle_dse() (dse.c:2874)

...

seems to be simple. Because of "delete_dead_store_insn (ptr);"

"s_info->redundant_reason" may point into lala land:



(gdb) p *s_info

$3 = {is_set = false, is_large = false, group_id = 0, cse_base =

0xafafafafafafafaf, mem = 0xafafafafafafafaf, mem_addr = 0xafafafafafafafaf,

alias_set = -1347440721, begin = -5787213827046133841, end =

-5787213827046133841, positions_needed = {small_bitmask = 12659530246663417775,

large = {bmap = 0xafafafafafafafaf, count = -1347440721}}, next =

0xafafafafafafafaf, rhs = 0xafafafafafafafaf, const_rhs = 0xafafafafafafafaf,

redundant_reason = 0xafafafafafafafaf}

(gdb) p *ptr

$8 = {cannot_delete = true, wild_read = false, non_frame_wild_read = false,

frame_read = false, stack_pointer_based = false, contains_cselib_groups =

false, insn = 0x0, store_rec = 0x0, read_rec = 0x0, fixed_regs_live =

0x5e34f30, prev_insn = 0x54e9da0, next_local_store = 0x54e9da0}





diff --git a/gcc/dse.c b/gcc/dse.c

index f879adb..8d12e8d 100644

--- a/gcc/dse.c

+++ b/gcc/dse.c

@@ -2869,7 +2869,7 @@ dse_step1 (void)

                                 INSN_UID (s_info->redundant_reason->insn));

                      delete_dead_store_insn (ptr);

                    }

-                 if (s_info)

+                 if (ptr->store_rec && s_info)

                    s_info->redundant_reason = NULL;

                  free_store_info (ptr);

                }