This should fix PR56525, we reference ggc_freed loop structures
from bb->loop_father when fix_loop_structure removes a loop
and then calls flow_loops_find. Fixed by delaying the ggc_free
part of loop removal until after that (I thought about other
ways to fix the reference but they are way more intrusive).
Bootstrap and regtest running on x86_64-unknown-linux-gnu.
Richard.
2013-03-05 Richard Biener <rguent...@suse.de>
PR middle-end/56525
* loop-init.c (fix_loop_structure): Remove loops in two stages,
not freeing them until the end.
Index: gcc/loop-init.c
===================================================================
*** gcc/loop-init.c (revision 196451)
--- gcc/loop-init.c (working copy)
*************** fix_loop_structure (bitmap changed_bbs)
*** 186,192 ****
int record_exits = 0;
loop_iterator li;
struct loop *loop;
! unsigned old_nloops;
timevar_push (TV_LOOP_INIT);
--- 186,192 ----
int record_exits = 0;
loop_iterator li;
struct loop *loop;
! unsigned old_nloops, i;
timevar_push (TV_LOOP_INIT);
*************** fix_loop_structure (bitmap changed_bbs)
*** 230,237 ****
flow_loop_tree_node_add (loop_outer (loop), ploop);
}
! /* Remove the loop and free its data. */
! delete_loop (loop);
}
/* Remember the number of loops so we can return how many new loops
--- 230,238 ----
flow_loop_tree_node_add (loop_outer (loop), ploop);
}
! /* Remove the loop. */
! loop->header = NULL;
! flow_loop_tree_node_remove (loop);
}
/* Remember the number of loops so we can return how many new loops
*************** fix_loop_structure (bitmap changed_bbs)
*** 253,258 ****
--- 254,267 ----
}
}
+ /* Finally free deleted loops. */
+ FOR_EACH_VEC_ELT (*get_loops (), i, loop)
+ if (loop && loop->header == NULL)
+ {
+ (*get_loops ())[i] = NULL;
+ flow_loop_free (loop);
+ }
+
loops_state_clear (LOOPS_NEED_FIXUP);
/* Apply flags to loops. */
