* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
@ 2012-10-07 12:42 ` mpolacek at gcc dot gnu.org
2012-10-07 12:45 ` mpolacek at gcc dot gnu.org
` (19 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-10-07 12:42 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2012-10-07
CC| |mpolacek at gcc dot gnu.org
Ever Confirmed|0 |1
--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-10-07 12:41:57 UTC ---
Confirmed.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
2012-10-07 12:42 ` [Bug middle-end/54838] " mpolacek at gcc dot gnu.org
@ 2012-10-07 12:45 ` mpolacek at gcc dot gnu.org
2012-10-08 12:05 ` rguenth at gcc dot gnu.org
` (18 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-10-07 12:45 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at gcc dot gnu.org
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-10-07 12:44:53 UTC ---
Started with http://gcc.gnu.org/viewcvs?view=revision&revision=185913
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
2012-10-07 12:42 ` [Bug middle-end/54838] " mpolacek at gcc dot gnu.org
2012-10-07 12:45 ` mpolacek at gcc dot gnu.org
@ 2012-10-08 12:05 ` rguenth at gcc dot gnu.org
2012-10-18 18:25 ` zsojka at seznam dot cz
` (17 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-10-08 12:05 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |4.8.0
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (2 preceding siblings ...)
2012-10-08 12:05 ` rguenth at gcc dot gnu.org
@ 2012-10-18 18:25 ` zsojka at seznam dot cz
2012-11-04 2:33 ` [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer mpolacek at gcc dot gnu.org
` (16 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: zsojka at seznam dot cz @ 2012-10-18 18:25 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #3 from Zdenek Sojka <zsojka at seznam dot cz> 2012-10-18 18:24:42 UTC ---
Created attachment 28486
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28486
another testcase
This ICE seems to happen quite often when testing with 'random' flags...
-ftracer seems to be the common denominator.
$ gcc -O2 -fno-forward-propagate -ftracer testcase.c
testcase.c: In function 'foo':
testcase.c:20:1: internal compiler error: in merge_latch_edges, at
cfgloop.c:678
}
^
linux-vdso.so.1: No such file or directory
0x6a7028 merge_latch_edges
/mnt/svn/gcc-trunk/gcc/cfgloop.c:678
0x6a7028 disambiguate_multiple_latches
/mnt/svn/gcc-trunk/gcc/cfgloop.c:741
0x6a7028 disambiguate_loops_with_multiple_latches()
/mnt/svn/gcc-trunk/gcc/cfgloop.c:755
0x8b2794 loop_optimizer_init(unsigned int)
/mnt/svn/gcc-trunk/gcc/loop-init.c:78
0x8b285a rtl_loop_initgcc -O2 -fno-forward-propagate -ftracer testcase.c
testcase.c: In function 'foo':
testcase.c:20:1: internal compiler error: in merge_latch_edges, at
cfgloop.c:678
}
^
linux-vdso.so.1: No such file or directory
0x6a7028 merge_latch_edges
/mnt/svn/gcc-trunk/gcc/cfgloop.c:678
0x6a7028 disambiguate_multiple_latches
/mnt/svn/gcc-trunk/gcc/cfgloop.c:741
0x6a7028 disambiguate_loops_with_multiple_latches()
/mnt/svn/gcc-trunk/gcc/cfgloop.c:755
0x8b2794 loop_optimizer_init(unsigned int)
/mnt/svn/gcc-trunk/gcc/loop-init.c:78
0x8b285a rtl_loop_init
/mnt/svn/gcc-trunk/gcc/loop-init.c:219
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
/mnt/svn/gcc-trunk/gcc/loop-init.c:219
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (3 preceding siblings ...)
2012-10-18 18:25 ` zsojka at seznam dot cz
@ 2012-11-04 2:33 ` mpolacek at gcc dot gnu.org
2012-11-04 12:49 ` mpolacek at gcc dot gnu.org
` (15 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-11-04 2:33 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
AssignedTo|unassigned at gcc dot |mpolacek at gcc dot gnu.org
|gnu.org |
--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-11-04 02:33:36 UTC ---
Looking into it.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (4 preceding siblings ...)
2012-11-04 2:33 ` [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer mpolacek at gcc dot gnu.org
@ 2012-11-04 12:49 ` mpolacek at gcc dot gnu.org
2012-11-08 9:12 ` mpolacek at gcc dot gnu.org
` (14 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-11-04 12:49 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-11-04 12:49:27 UTC ---
I think the problem is that we somehow arrive at this:
loop_1 (header = 2, multiple latches, niter = )
{
bb_2 (preds = {bb_0 }, succs = {bb_4 bb_3 })
{
(note 5 0 2 2 [bb 2] NOTE_INSN_BASIC_BLOCK)
(insn 2 5 3 2 (set (reg/v/f:DI 60 [ b ])
(reg:DI 5 di [ b ])) ./pr54838.c:5 63 {*movdi_internal_rex64}
(nil))
(insn 3 2 4 2 (set (reg/v/f:DI 61 [ c ])
(reg:DI 4 si [ c ])) ./pr54838.c:5 63 {*movdi_internal_rex64}
(nil))
(note 4 3 7 2 NOTE_INSN_FUNCTION_BEG)
(insn 7 4 14 2 (set (reg:SI 59 [ D.1735 ])
(mem:SI (reg/v/f:DI 61 [ c ]) [2 *c_3(D)+0 S4 A32])) 65
{*movsi_internal}
(nil))
(insn 14 7 15 2 (set (reg:CCZ 17 flags)
(compare:CCZ (reg:SI 59 [ D.1735 ])
(const_int 1 [0x1]))) ./pr54838.c:7 7 {*cmpsi_1}
(nil))
(jump_insn 15 14 38 2 (set (pc)
(if_then_else (eq (reg:CCZ 17 flags)
(const_int 0 [0]))
(label_ref:DI 20)
(pc))) ./pr54838.c:7 595 {*jcc_1}
(expr_list:REG_BR_PROB (const_int 3333 [0xd05])
(nil))
-> 20)
}
}
, i.e. we have a loop which contains only the header. The rest of BBs are
there, but in loop_0. When we call disambiguate_loops_with_multiple_latches,
loop->latch is NULL on that loop, so we end up calling merge_latch_edges, but
that ICEs because VEC_length (edge, latches) is of course 0.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (5 preceding siblings ...)
2012-11-04 12:49 ` mpolacek at gcc dot gnu.org
@ 2012-11-08 9:12 ` mpolacek at gcc dot gnu.org
2012-11-24 11:53 ` mpolacek at gcc dot gnu.org
` (13 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-11-08 9:12 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-11-08 09:12:01 UTC ---
And I'd say that something in bypass_block from cprop.c is the culprit. Not
calling bypass_block -> no ICE, and compilation proceeds fine. Working on a
patch.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (6 preceding siblings ...)
2012-11-08 9:12 ` mpolacek at gcc dot gnu.org
@ 2012-11-24 11:53 ` mpolacek at gcc dot gnu.org
2012-11-26 14:30 ` mpolacek at gcc dot gnu.org
` (12 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-11-24 11:53 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-11-24 11:53:19 UTC ---
So, in .cse1 we have:
ENTRY
|
|
2
|
|
+-------- 4 ----------+
| / \ |
| / \ |
| 6 5 |
| /\ |\ |
| / \ | \ |
| 7 3 | 8 |
| | | | /\ /
+---|----| | / \ /
| --10 9/
| -/
EXIT-/
(3->4 and 9->4 are back edges). Now, in bypass_block, when we're trying to
bypass BB 4, we iterate over BB 4's incoming edges. We skip certain edges
(e.g. complex), then we're iterating over reg_use_table (registers used in
insn). Here we call
set = find_bypass_set (regno, e->src->index);
If set == NULL, we skip to another iteration. But in this case the set is not
NULL, and we end up with this:
Redirecting fallthru edge 3->4 to 6
JUMP-BYPASS: Proved reg 59 in jump_insn 15 equals constant (const_int 1 [0x1])
Bypass edge from 3->4 to 6
Redirecting fallthru edge 9->4 to 5
JUMP-BYPASS: Proved reg 59 in jump_insn 15 equals constant (const_int 3 [0x3])
Bypass edge from 9->4 to 5
but how can be two different constants in one reg? The hash table is:
SET hash table (11 buckets, 3 entries)
Index 0 (hash value 4)
(reg:SI 59 [ D.1735 ]) := (const_int 1 [0x1])
Index 1 (hash value 5)
(reg/v/f:DI 60 [ b ]) := (const_int 0 [0])
Index 2 (hash value 4)
(reg:SI 59 [ D.1735 ]) := (const_int 3 [0x3])
redirect_edge_and_branch_force then redirect edges and BB 4 is gone.
I'd say we cannot redirect edges of BBs which have 2 and more incoming back
edges if in the hash table there are more entries with the same hash values,
but the SRC rtx's differ. I'll post something to ML.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (7 preceding siblings ...)
2012-11-24 11:53 ` mpolacek at gcc dot gnu.org
@ 2012-11-26 14:30 ` mpolacek at gcc dot gnu.org
2012-12-02 20:17 ` mpolacek at gcc dot gnu.org
` (11 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-11-26 14:30 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #8 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-11-26 14:29:59 UTC ---
Patch posted: http://gcc.gnu.org/ml/gcc-patches/2012-11/msg02095.html
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (8 preceding siblings ...)
2012-11-26 14:30 ` mpolacek at gcc dot gnu.org
@ 2012-12-02 20:17 ` mpolacek at gcc dot gnu.org
2012-12-02 20:18 ` mpolacek at gcc dot gnu.org
` (10 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-12-02 20:17 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #9 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-12-02 20:17:16 UTC ---
Author: mpolacek
Date: Sun Dec 2 20:16:09 2012
New Revision: 194060
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194060
Log:
PR54838
Added:
trunk/gcc/testsuite/gcc.dg/pr54838.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/cprop.c
trunk/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (9 preceding siblings ...)
2012-12-02 20:17 ` mpolacek at gcc dot gnu.org
@ 2012-12-02 20:18 ` mpolacek at gcc dot gnu.org
2012-12-03 9:28 ` mpolacek at gcc dot gnu.org
` (9 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-12-02 20:18 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
--- Comment #10 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-12-02 20:17:54 UTC ---
Fixed.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (10 preceding siblings ...)
2012-12-02 20:18 ` mpolacek at gcc dot gnu.org
@ 2012-12-03 9:28 ` mpolacek at gcc dot gnu.org
2012-12-07 11:47 ` rguenth at gcc dot gnu.org
` (8 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-12-03 9:28 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
Resolution|FIXED |
--- Comment #11 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-12-03 09:28:38 UTC ---
Oh, but the C++ testcase still ICEs...
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (11 preceding siblings ...)
2012-12-03 9:28 ` mpolacek at gcc dot gnu.org
@ 2012-12-07 11:47 ` rguenth at gcc dot gnu.org
2012-12-14 14:59 ` jakub at gcc dot gnu.org
` (7 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-12-07 11:47 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P1
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (12 preceding siblings ...)
2012-12-07 11:47 ` rguenth at gcc dot gnu.org
@ 2012-12-14 14:59 ` jakub at gcc dot gnu.org
2012-12-14 15:23 ` jakub at gcc dot gnu.org
` (6 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-12-14 14:59 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-12-14 14:58:41 UTC ---
I see the same ICE also during bootstrap if ada/targparm.adb is built with
-fstack-protector (I have -fstack-protector in CFLAGS/CXXFLAGS/XCFLAGS/TCFLAGS
during configure among other things):
/home/jakub/rpmbuild/BUILD/gcc-4.8.0-20121213/obj-x86_64-redhat-linux/./prev-gcc/xgcc
-B/home/jakub/rpmbuild/BUILD/gcc-4.8.0-20121213/obj-x86_64-redhat-linux/./prev-gcc/
-isystem /usr/x86_64-redhat-linux/include -isystem
/usr/x86_64-redhat-linux/sys-include -c -O2 -fstack-protector -gnatpg -gnata
-gnatwns -W -Wall -nostdinc -I- -I. -Iada -I../../gcc/ada
-I../../gcc/ada/gcc-interface ../../gcc/ada/targparm.adb -o ada/targparm.o
+===========================GNAT BUG DETECTED==============================+
| 4.8.0 20121213 (Red Hat 4.8.0-0.1) (x86_64-redhat-linux) GCC error: |
| in merge_latch_edges, at cfgloop.c:678 |
| Error detected around ../../gcc/ada/targparm.adb:649:8 |
| Please submit a bug report; see http://gcc.gnu.org/bugs.html. |
...
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (13 preceding siblings ...)
2012-12-14 14:59 ` jakub at gcc dot gnu.org
@ 2012-12-14 15:23 ` jakub at gcc dot gnu.org
2012-12-14 15:53 ` jakub at gcc dot gnu.org
` (5 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-12-14 15:23 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-12-14 15:22:37 UTC ---
Actually it is either -fstack-protector or -fprofile-generate or both that
trigger it. Haven't tried vanilla trunk profiledbootstrap though yet.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (14 preceding siblings ...)
2012-12-14 15:23 ` jakub at gcc dot gnu.org
@ 2012-12-14 15:53 ` jakub at gcc dot gnu.org
2012-12-14 16:13 ` mpolacek at gcc dot gnu.org
` (4 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-12-14 15:53 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-12-14 15:53:30 UTC ---
Ok, reproduced with vanilla trunk, starting from gcc 4.7.2:
../configure --enable-languages=all,obj-c++,ada,go --enable-checking=release
make -j48 profiledbootstrap
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (15 preceding siblings ...)
2012-12-14 15:53 ` jakub at gcc dot gnu.org
@ 2012-12-14 16:13 ` mpolacek at gcc dot gnu.org
2012-12-14 16:15 ` mpolacek at gcc dot gnu.org
` (3 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-12-14 16:13 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #15 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-12-14 16:12:48 UTC ---
The issue here is that we have a loop with header and two latches, and via
delete_basic_block we delete both latches (and all edges of those two latches).
So, we don't have a loop anymore, but the header has still loop_depth > 0,
merge_latch_edges of course ICEs on it, because there's an assert:
gcc_assert (latches.length () > 0);
but the latches are already gone. I think that in this case we want to just
set the loop->header to NULL (or cancel_loop_tree, or unloop, or...). What I
have in mind is basically something like:
--- a/gcc/cfghooks.c
+++ b/gcc/cfghooks.c
@@ -552,6 +552,23 @@ delete_basic_block (basic_block bb)
loops_state_set (LOOPS_NEED_FIXUP);
}
+ if (loop->header
+ && bb->loop_father != current_loops->tree_root)
+ {
+ edge_iterator ei;
+ edge e;
+ unsigned n_back_edges = 0;
+
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
+ if (e->flags & EDGE_DFS_BACK)
+ n_back_edges++;
+
+ if (n_back_edges == 0)
+ {
+ loop->header = NULL;
+ loops_state_set (LOOPS_NEED_FIXUP);
+ }
+ }
remove_bb_from_loops (bb);
}
this fixes this ICE, but causes other ICEs.
I'd be really really grateful for any hints.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (16 preceding siblings ...)
2012-12-14 16:13 ` mpolacek at gcc dot gnu.org
@ 2012-12-14 16:15 ` mpolacek at gcc dot gnu.org
2012-12-14 16:38 ` mpolacek at gcc dot gnu.org
` (2 subsequent siblings)
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-12-14 16:15 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #16 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-12-14 16:14:58 UTC ---
(The reason why we don't have a loop anymore is simply that the header doesn't
have any incoming back edges after removing the latches. There of course may
be other loops in the CFG.)
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (17 preceding siblings ...)
2012-12-14 16:15 ` mpolacek at gcc dot gnu.org
@ 2012-12-14 16:38 ` mpolacek at gcc dot gnu.org
2012-12-18 14:40 ` rguenth at gcc dot gnu.org
2012-12-18 14:41 ` rguenth at gcc dot gnu.org
20 siblings, 0 replies; 22+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2012-12-14 16:38 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #17 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-12-14 16:37:39 UTC ---
Now I don't know why we'd need that hunk, the code for handling latch/header is
just above it, only loop->latch is NULL, because there are more of them. Sorry
for the noise, I'll be looking into it over the weekend.
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (18 preceding siblings ...)
2012-12-14 16:38 ` mpolacek at gcc dot gnu.org
@ 2012-12-18 14:40 ` rguenth at gcc dot gnu.org
2012-12-18 14:41 ` rguenth at gcc dot gnu.org
20 siblings, 0 replies; 22+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-12-18 14:40 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
--- Comment #18 from Richard Biener <rguenth at gcc dot gnu.org> 2012-12-18 14:39:55 UTC ---
Author: rguenth
Date: Tue Dec 18 14:39:49 2012
New Revision: 194582
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194582
Log:
2012-12-18 Richard Biener <rguenther@suse.de>
PR middle-end/54838
* cfgloopmanip.c (fix_loop_structure): Re-discover latch
edges first and mark loops for removal if no latch edges remain.
Properly re-create LOOPS_HAVE_FALLTHRU_PREHEADERS.
* loop-init.c (loop_optimizer_finalize): Set
LOOPS_MAY_HAVE_MULTIPLE_LATCHES.
* g++.dg/torture/pr54838.C: New testcase.
Added:
trunk/gcc/testsuite/g++.dg/torture/pr54838.C
Modified:
trunk/gcc/ChangeLog
trunk/gcc/cfgloopmanip.c
trunk/gcc/loop-init.c
trunk/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 22+ messages in thread* [Bug middle-end/54838] [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer
2012-10-06 18:19 [Bug middle-end/54838] New: [4.8 Regression] ICE: in merge_latch_edges, at cfgloop.c:678 with -O2 -ftracer -fno-tree-dce -fno-tree-sra zsojka at seznam dot cz
` (19 preceding siblings ...)
2012-12-18 14:40 ` rguenth at gcc dot gnu.org
@ 2012-12-18 14:41 ` rguenth at gcc dot gnu.org
20 siblings, 0 replies; 22+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-12-18 14:41 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54838
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|REOPENED |RESOLVED
Resolution| |FIXED
--- Comment #19 from Richard Biener <rguenth at gcc dot gnu.org> 2012-12-18 14:40:28 UTC ---
Fixed.
^ permalink raw reply [flat|nested] 22+ messages in thread