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* [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2)
@ 2010-01-26 18:45 zsojka at seznam dot cz
2010-01-26 18:46 ` [Bug tree-optimization/42878] " zsojka at seznam dot cz
` (7 more replies)
0 siblings, 8 replies; 9+ messages in thread
From: zsojka at seznam dot cz @ 2010-01-26 18:45 UTC (permalink / raw)
To: gcc-bugs
Command line:
gcc -O1 -fcompare-debug -c testcase.c
Tested revisions:
r156253 - crash
r155920 - crash
r155833 - crash
r155363 - crash
r154886 - crash
r154830 - OK
r153685 - OK
Output:
$ /mnt/svn/gcc-trunk/binary-156253-lto/bin/gcc -O1 -fcompare-debug -c
testcase.c
gcc: testcase.c: -fcompare-debug failure
--
Summary: "-fcompare-debug failure" at -O1 (2)
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: zsojka at seznam dot cz
GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42878
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug tree-optimization/42878] "-fcompare-debug failure" at -O1 (2)
2010-01-26 18:45 [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2) zsojka at seznam dot cz
@ 2010-01-26 18:46 ` zsojka at seznam dot cz
2010-01-26 19:31 ` zsojka at seznam dot cz
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: zsojka at seznam dot cz @ 2010-01-26 18:46 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from zsojka at seznam dot cz 2010-01-26 18:46 -------
Created an attachment (id=19717)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19717&action=view)
reduced testcase
Reduced from gcc/builtins.c
Command line:
gcc -O1 -fcompare-debug -c pr42878.c
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42878
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug tree-optimization/42878] "-fcompare-debug failure" at -O1 (2)
2010-01-26 18:45 [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2) zsojka at seznam dot cz
2010-01-26 18:46 ` [Bug tree-optimization/42878] " zsojka at seznam dot cz
@ 2010-01-26 19:31 ` zsojka at seznam dot cz
2010-01-27 10:43 ` rguenth at gcc dot gnu dot org
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: zsojka at seznam dot cz @ 2010-01-26 19:31 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from zsojka at seznam dot cz 2010-01-26 19:30 -------
Created an attachment (id=19718)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19718&action=view)
different reduced testcase
Reduced from gcc/builtins.c as well
This testcase started failing between r154830 and r154886 as well, so I am not
creating separate bugport for it.
All tested revisions fail at -O1, -O2 and -O3.
Command line:
gcc -O1 -fcompare-debug -c pr42878-2.c
or
gcc -O2 -fcompare-debug -c pr42878-2.c
or
gcc -O3 -fcompare-debug -c pr42878-2.c
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42878
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug tree-optimization/42878] "-fcompare-debug failure" at -O1 (2)
2010-01-26 18:45 [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2) zsojka at seznam dot cz
2010-01-26 18:46 ` [Bug tree-optimization/42878] " zsojka at seznam dot cz
2010-01-26 19:31 ` zsojka at seznam dot cz
@ 2010-01-27 10:43 ` rguenth at gcc dot gnu dot org
2010-01-27 11:26 ` rguenth at gcc dot gnu dot org
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2010-01-27 10:43 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from rguenth at gcc dot gnu dot org 2010-01-27 10:42 -------
Confirmed. It's loop header copying, or rather gimple_duplicate_sese_region,
that causes SSA name differences.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2010-01-27 10:42:56
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42878
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug tree-optimization/42878] "-fcompare-debug failure" at -O1 (2)
2010-01-26 18:45 [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2) zsojka at seznam dot cz
` (2 preceding siblings ...)
2010-01-27 10:43 ` rguenth at gcc dot gnu dot org
@ 2010-01-27 11:26 ` rguenth at gcc dot gnu dot org
2010-01-27 11:43 ` rguenth at gcc dot gnu dot org
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2010-01-27 11:26 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from rguenth at gcc dot gnu dot org 2010-01-27 11:26 -------
But the root cause is SSA names get out-of sync already during early inlining
via .MEMs. Which is because with debug isns we retain j_11 = 0 in
<bb 5>:
# VUSE <.MEM_12>
D.xxxx_10 = s_9->i;
# .MEM_14 = VDEF <.MEM_12>
e2 (D.xxxx_10);
# DEBUG i => i_1(D)
j_11 = 0;
# DEBUG j => j_11
# .MEM_15 = VDEF <.MEM_14>
e2 (i_1(D));
# DEBUG j => NULL
return;
while without it's gone.
<bb 5>:
# VUSE <.MEM_11>
D.xxxx_10 = s_9->i;
# .MEM_13 = VDEF <.MEM_11>
e2 (D.xxxx_10);
# .MEM_14 = VDEF <.MEM_13>
e2 (i_1(D));
return;
This is because
/* By inlining function having uninitialized variable, we might
extend the lifetime (variable might get reused). This cause
ICE in the case we end up extending lifetime of SSA name across
abnormal edge, but also increase register pressure.
We simply initialize all uninitialized vars by 0 except
for case we are inlining to very first BB. We can avoid
this for all BBs that are not inside strongly connected
regions of the CFG, but this is expensive to test. */
if (id->entry_bb
&& is_gimple_reg (SSA_NAME_VAR (name))
&& TREE_CODE (SSA_NAME_VAR (name)) != PARM_DECL
&& (id->entry_bb != EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->dest
|| EDGE_COUNT (id->entry_bb->preds) != 1))
{
gimple_stmt_iterator gsi = gsi_last_bb (id->entry_bb);
gimple init_stmt;
init_stmt = gimple_build_assign (new_tree,
fold_convert (TREE_TYPE
(new_tree),
integer_zero_node));
inserts this assignment also if there are only debug-uses. We come along
here from re-mapping the default-defs of decls.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42878
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug tree-optimization/42878] "-fcompare-debug failure" at -O1 (2)
2010-01-26 18:45 [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2) zsojka at seznam dot cz
` (3 preceding siblings ...)
2010-01-27 11:26 ` rguenth at gcc dot gnu dot org
@ 2010-01-27 11:43 ` rguenth at gcc dot gnu dot org
2010-01-27 12:28 ` zsojka at seznam dot cz
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2010-01-27 11:43 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from rguenth at gcc dot gnu dot org 2010-01-27 11:43 -------
I have a patch.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot
|dot org |org
Status|NEW |ASSIGNED
Last reconfirmed|2010-01-27 10:42:56 |2010-01-27 11:43:16
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42878
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug tree-optimization/42878] "-fcompare-debug failure" at -O1 (2)
2010-01-26 18:45 [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2) zsojka at seznam dot cz
` (4 preceding siblings ...)
2010-01-27 11:43 ` rguenth at gcc dot gnu dot org
@ 2010-01-27 12:28 ` zsojka at seznam dot cz
2010-01-27 16:01 ` rguenth at gcc dot gnu dot org
2010-01-27 16:01 ` rguenth at gcc dot gnu dot org
7 siblings, 0 replies; 9+ messages in thread
From: zsojka at seznam dot cz @ 2010-01-27 12:28 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from zsojka at seznam dot cz 2010-01-27 12:28 -------
Created an attachment (id=19726)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19726&action=view)
different testcase, not crashing, but having difference in einline2 dump
This testcase passes the compare-debug test, but shows the behaviour you
described. In this case, there are no uninitialized variables though (I am not
aware of any). I hope this file can be useful.
Command line:
gcc -O1 -fcompare-debug testcase.c -c -fdump-tree-einline2
diff testcase.c.*024t.einline2
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42878
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug tree-optimization/42878] "-fcompare-debug failure" at -O1 (2)
2010-01-26 18:45 [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2) zsojka at seznam dot cz
` (5 preceding siblings ...)
2010-01-27 12:28 ` zsojka at seznam dot cz
@ 2010-01-27 16:01 ` rguenth at gcc dot gnu dot org
2010-01-27 16:01 ` rguenth at gcc dot gnu dot org
7 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2010-01-27 16:01 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from rguenth at gcc dot gnu dot org 2010-01-27 16:00 -------
Subject: Bug 42878
Author: rguenth
Date: Wed Jan 27 16:00:31 2010
New Revision: 156291
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=156291
Log:
2010-01-27 Richard Guenther <rguenther@suse.de>
PR middle-end/42878
* tree-inline.c (remap_decl): Delay remapping of SSA name
default definitions until we need them.
* gcc.dg/torture/pr42878-1.c: New testcase.
* gcc.dg/torture/pr42878-2.c: Likewise.
Added:
trunk/gcc/testsuite/gcc.dg/torture/pr42878-1.c
trunk/gcc/testsuite/gcc.dg/torture/pr42878-2.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/testsuite/ChangeLog
trunk/gcc/tree-inline.c
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42878
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug tree-optimization/42878] "-fcompare-debug failure" at -O1 (2)
2010-01-26 18:45 [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2) zsojka at seznam dot cz
` (6 preceding siblings ...)
2010-01-27 16:01 ` rguenth at gcc dot gnu dot org
@ 2010-01-27 16:01 ` rguenth at gcc dot gnu dot org
7 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2010-01-27 16:01 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from rguenth at gcc dot gnu dot org 2010-01-27 16:00 -------
Subject: Bug 42878
Author: rguenth
Date: Wed Jan 27 16:00:31 2010
New Revision: 156291
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=156291
Log:
2010-01-27 Richard Guenther <rguenther@suse.de>
PR middle-end/42878
* tree-inline.c (remap_decl): Delay remapping of SSA name
default definitions until we need them.
* gcc.dg/torture/pr42878-1.c: New testcase.
* gcc.dg/torture/pr42878-2.c: Likewise.
Added:
trunk/gcc/testsuite/gcc.dg/torture/pr42878-1.c
trunk/gcc/testsuite/gcc.dg/torture/pr42878-2.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/testsuite/ChangeLog
trunk/gcc/tree-inline.c
------- Comment #8 from rguenth at gcc dot gnu dot org 2010-01-27 16:01 -------
Fixed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
Target Milestone|--- |4.5.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42878
^ permalink raw reply [flat|nested] 9+ messages in thread
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2010-01-26 18:45 [Bug tree-optimization/42878] New: "-fcompare-debug failure" at -O1 (2) zsojka at seznam dot cz
2010-01-26 18:46 ` [Bug tree-optimization/42878] " zsojka at seznam dot cz
2010-01-26 19:31 ` zsojka at seznam dot cz
2010-01-27 10:43 ` rguenth at gcc dot gnu dot org
2010-01-27 11:26 ` rguenth at gcc dot gnu dot org
2010-01-27 11:43 ` rguenth at gcc dot gnu dot org
2010-01-27 12:28 ` zsojka at seznam dot cz
2010-01-27 16:01 ` rguenth at gcc dot gnu dot org
2010-01-27 16:01 ` rguenth at gcc dot gnu dot org
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