http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51460
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2011-12-08
Component|c++ |middle-end
Target Milestone|--- |4.6.3
Summary|[4.6 regression] Struct |[4.6/4.7 Regression] Struct
|with two boost mutexes |with two boost mutexes
|allocated on the heap |allocated on the heap
|inside of a while loop |inside of a while loop
|causes compiler segfault |causes compiler segfault
Ever Confirmed|0 |1
--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-12-08
10:05:34 UTC ---
Confirmed with -O1.
Program received signal SIGSEGV, Segmentation fault.
0x0000000000bb9511 in VEC_edge_base_index (vec_=0x7ffff52e2cf8, ix_=0,
file_=Cannot access memory at address 0x7fffff7feff8
)
at /space/rguenther/src/svn/gcc-4_6-branch/gcc/basic-block.h:64
64 DEF_VEC_P(edge);
(gdb) bt
#1 0x0000000000bb9500 in ei_edge (i=...)
at /space/rguenther/src/svn/gcc-4_6-branch/gcc/basic-block.h:671
#2 0x0000000000bb942d in ei_cond (ei=..., p=0x7fffff7ff0e8)
at /space/rguenther/src/svn/gcc-4_6-branch/gcc/basic-block.h:692
#3 0x0000000000bbdd75 in predict_paths_for_bb (cur=0x7ffff19a3888,
bb=0x7ffff1b2f270, pred=PRED_CONTINUE, taken=NOT_TAKEN)
at /space/rguenther/src/svn/gcc-4_6-branch/gcc/predict.c:1801
#4 0x0000000000bbdda6 in predict_paths_for_bb (cur=0x7ffff1b2f270,
bb=0x7ffff1b2f270, pred=PRED_CONTINUE, taken=NOT_TAKEN)
at /space/rguenther/src/svn/gcc-4_6-branch/gcc/predict.c:1836
...
we endlessly recurse in predict_paths_for_bb walking
for (son = first_dom_son (CDI_POST_DOMINATORS, cur);
son;
son = next_dom_son (CDI_POST_DOMINATORS, son))
predict_paths_for_bb (son, bb, pred, taken);
(we never do anything else in the loop above it). Sequence of recursion
is (cur, bb): (7, 9) (3, 3) (9, 9) (7, 9) ...
;; basic block 2, loop depth 0, count 0
;; prev block 0, next block 9
;; pred: ENTRY (fallthru,exec)
;; succ: 9 [100.0%] (fallthru)
<bb 2>:
;; basic block 9, loop depth 1, count 0
;; prev block 2, next block 3
;; pred: 2 [100.0%] (fallthru) 7 (fallthru,exec)
;; succ: 3 [100.0%] (fallthru,exec) 8 (eh,exec)
<bb 9>:
f_1 = operator new (80);
D.102841_9 = &f_1->bar;
boost::mutex::mutex (D.102841_9);
;; basic block 3, loop depth 1, count 0
;; prev block 9, next block 4
;; pred: 9 [100.0%] (fallthru,exec)
;; succ: 7 [100.0%] (fallthru,exec) 4 (eh,exec)
<bb 3>:
D.102840_10 = &f_1->baz;
boost::mutex::mutex (D.102840_10);
goto <bb 7>;
;; basic block 7, loop depth 1, count 0
;; prev block 6, next block 8
;; pred: 3 [100.0%] (fallthru,exec)
;; succ: 9 (fallthru,exec)
<bb 7>:
// predicted unlikely by continue predictor.
goto <bb 9>;
... so it seems post-dominators do not honor EH-edges, or at least
it is inconsistent with the way we add fake exit edges for infinite
loops.
