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* [Bug optimization/13521] New: Endless loop in calculate_global_regs_live
@ 2003-12-30 15:36 jakub at gcc dot gnu dot org
2003-12-30 20:01 ` [Bug optimization/13521] [3.3 only] " pinskia at gcc dot gnu dot org
` (8 more replies)
0 siblings, 9 replies; 10+ messages in thread
From: jakub at gcc dot gnu dot org @ 2003-12-30 15:36 UTC (permalink / raw)
To: gcc-bugs
Following testcase at -O2 and higher loops forever in calculate_global_regs_live.
extern int f1 (int, void *);
extern int *f2 (void) __attribute__ ((__const__));
extern int f3 (int, void *);
int
test (int x, char *y, int z)
{
int b = 0;
if (x < 1024)
{
y[0] = '\0';
do
{
switch (f1 (x, y + b))
{
case -1:
if (b == 0)
return -1;
else
return b;
default:
b++;
}
}
while (y[b - 1] != '\0' && y[b - 1] != '\n' && b < z);
}
else
{
do
{
switch (f3 (x, y + b))
{
case -1:
if ((*f2 ()) == 4)
continue;
if (b == 0)
return -1;
else
return b;
default:
b++;
}
}
while (y[b - 1] != '\0' && y[b - 1] != '\n' && b < z);
}
return b;
}
The problem seems to be that 1) cse finds out that the -1 constant in both return -1;
statements is already in the pseudo holding return value of f1() resp. f3()
and changes (set (reg:SI X) (const_int -1)) to (set (reg:SI X) (reg:SI Y)) REG_EQUAL (const_int -1).
2) during reload, this pseudo (Y above) is %eax after f1() and %r14d after f3()
(as in the latter case there is another function call in between)
3) during flow2 GCC replaces the pseudo with REG_EQUAL, so it is again:
(set (reg:SI %edx) (const_int -1)) REG_DEAD %r14d REG_EQUAL (const_int -1)
(in the f3() case and then merges both return -1's together).
The problem is REG_DEAD %r14d now, because it is set only in one of the predecessors
of the merged basic block, which causes the endless loop in calculate_global_regs_live
(as it keeps alternating between having %r14 live and not having it live).
Should cfg* not attempt to merge if there are different REG_DEAD notes
or do you have other ideas?
--
Summary: Endless loop in calculate_global_regs_live
Product: gcc
Version: 3.3.3
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jakub at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org,jh at suse dot cz,rth at
redhat dot com
GCC build triplet: *-*-*
GCC host triplet: *-*-*
GCC target triplet: x86_64-redhat-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug optimization/13521] [3.3 only] Endless loop in calculate_global_regs_live
2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
@ 2003-12-30 20:01 ` pinskia at gcc dot gnu dot org
2003-12-30 20:04 ` ebotcazou at gcc dot gnu dot org
` (7 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2003-12-30 20:01 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2003-12-30 19:38 -------
It does not happen on the mainline though. I do not think this will ever be fixed for 3.3.3 though.
--
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |ice-on-valid-code
Summary|Endless loop in |[3.3 only] Endless loop in
|calculate_global_regs_live |calculate_global_regs_live
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug optimization/13521] [3.3 only] Endless loop in calculate_global_regs_live
2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
2003-12-30 20:01 ` [Bug optimization/13521] [3.3 only] " pinskia at gcc dot gnu dot org
@ 2003-12-30 20:04 ` ebotcazou at gcc dot gnu dot org
2003-12-30 20:06 ` ebotcazou at gcc dot gnu dot org
` (6 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: ebotcazou at gcc dot gnu dot org @ 2003-12-30 20:04 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From ebotcazou at gcc dot gnu dot org 2003-12-30 19:43 -------
For another example of endless loop in c_g_r_l see PR opt/12158.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug optimization/13521] [3.3 only] Endless loop in calculate_global_regs_live
2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
2003-12-30 20:01 ` [Bug optimization/13521] [3.3 only] " pinskia at gcc dot gnu dot org
2003-12-30 20:04 ` ebotcazou at gcc dot gnu dot org
@ 2003-12-30 20:06 ` ebotcazou at gcc dot gnu dot org
2003-12-31 15:05 ` jakub at gcc dot gnu dot org
` (5 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: ebotcazou at gcc dot gnu dot org @ 2003-12-30 20:06 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |ebotcazou at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug optimization/13521] [3.3 only] Endless loop in calculate_global_regs_live
2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
` (2 preceding siblings ...)
2003-12-30 20:06 ` ebotcazou at gcc dot gnu dot org
@ 2003-12-31 15:05 ` jakub at gcc dot gnu dot org
2003-12-31 17:31 ` pinskia at gcc dot gnu dot org
` (4 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: jakub at gcc dot gnu dot org @ 2003-12-31 15:05 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From jakub at gcc dot gnu dot org 2003-12-31 11:59 -------
Fixed on mainline with:
http://gcc.gnu.org/ml/gcc-patches/2003-04/msg01324.html
Will post to gcc-patches.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug optimization/13521] [3.3 only] Endless loop in calculate_global_regs_live
2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
` (3 preceding siblings ...)
2003-12-31 15:05 ` jakub at gcc dot gnu dot org
@ 2003-12-31 17:31 ` pinskia at gcc dot gnu dot org
2004-01-01 13:19 ` cvs-commit at gcc dot gnu dot org
` (3 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2003-12-31 17:31 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2003-12-31 16:06 -------
Patch here: <http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02314.html>.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed| |1
Keywords| |patch
Last reconfirmed|0000-00-00 00:00:00 |2003-12-31 16:06:09
date| |
Target Milestone|--- |3.3.3
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug optimization/13521] [3.3 only] Endless loop in calculate_global_regs_live
2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
` (4 preceding siblings ...)
2003-12-31 17:31 ` pinskia at gcc dot gnu dot org
@ 2004-01-01 13:19 ` cvs-commit at gcc dot gnu dot org
2004-01-01 13:21 ` cvs-commit at gcc dot gnu dot org
` (2 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: cvs-commit at gcc dot gnu dot org @ 2004-01-01 13:19 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From cvs-commit at gcc dot gnu dot org 2004-01-01 13:19 -------
Subject: Bug 13521
CVSROOT: /cvs/gcc
Module name: gcc
Branch: gcc-3_3-branch
Changes by: jakub@gcc.gnu.org 2004-01-01 13:19:41
Modified files:
gcc : ChangeLog cfgcleanup.c
gcc/testsuite : ChangeLog
Added files:
gcc/testsuite/gcc.c-torture/compile: 20031231-1.c
Log message:
PR optimization/13521
Backport from mainline:
2003-03-22 Richard Henderson <rth@redhat.com>
* cfgcleanup.c (insns_match_p): Do not do EQUIV substitution
after reload.
* gcc.c-torture/compile/20031231-1.c: New test.
Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=1.16114.2.865&r2=1.16114.2.866
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cfgcleanup.c.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=1.68.2.8&r2=1.68.2.9
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=1.2261.2.349&r2=1.2261.2.350
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.c-torture/compile/20031231-1.c.diff?cvsroot=gcc&only_with_tag=gcc-3_3-branch&r1=NONE&r2=1.1.2.1
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug optimization/13521] [3.3 only] Endless loop in calculate_global_regs_live
2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
` (5 preceding siblings ...)
2004-01-01 13:19 ` cvs-commit at gcc dot gnu dot org
@ 2004-01-01 13:21 ` cvs-commit at gcc dot gnu dot org
2004-01-01 15:32 ` pinskia at gcc dot gnu dot org
2004-03-03 12:54 ` ebotcazou at gcc dot gnu dot org
8 siblings, 0 replies; 10+ messages in thread
From: cvs-commit at gcc dot gnu dot org @ 2004-01-01 13:21 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From cvs-commit at gcc dot gnu dot org 2004-01-01 13:21 -------
Subject: Bug 13521
CVSROOT: /cvs/gcc
Module name: gcc
Changes by: jakub@gcc.gnu.org 2004-01-01 13:21:18
Modified files:
gcc/testsuite : ChangeLog
Added files:
gcc/testsuite/gcc.c-torture/compile: 20031231-1.c
Log message:
PR optimization/13521
* gcc.c-torture/compile/20031231-1.c: New test.
Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.3327&r2=1.3328
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.c-torture/compile/20031231-1.c.diff?cvsroot=gcc&r1=1.1&r2=1.2
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug optimization/13521] [3.3 only] Endless loop in calculate_global_regs_live
2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
` (6 preceding siblings ...)
2004-01-01 13:21 ` cvs-commit at gcc dot gnu dot org
@ 2004-01-01 15:32 ` pinskia at gcc dot gnu dot org
2004-03-03 12:54 ` ebotcazou at gcc dot gnu dot org
8 siblings, 0 replies; 10+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-01-01 15:32 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-01-01 15:32 -------
Fixed for 3.3.3 and already for 3.4.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug optimization/13521] [3.3 only] Endless loop in calculate_global_regs_live
2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
` (7 preceding siblings ...)
2004-01-01 15:32 ` pinskia at gcc dot gnu dot org
@ 2004-03-03 12:54 ` ebotcazou at gcc dot gnu dot org
8 siblings, 0 replies; 10+ messages in thread
From: ebotcazou at gcc dot gnu dot org @ 2004-03-03 12:54 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From ebotcazou at gcc dot gnu dot org 2004-03-03 12:54 -------
*** Bug 14335 has been marked as a duplicate of this bug. ***
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |r dot s dot a dot vandomburg
| |at student dot utwente dot
| |nl
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13521
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2003-12-30 15:36 [Bug optimization/13521] New: Endless loop in calculate_global_regs_live jakub at gcc dot gnu dot org
2003-12-30 20:01 ` [Bug optimization/13521] [3.3 only] " pinskia at gcc dot gnu dot org
2003-12-30 20:04 ` ebotcazou at gcc dot gnu dot org
2003-12-30 20:06 ` ebotcazou at gcc dot gnu dot org
2003-12-31 15:05 ` jakub at gcc dot gnu dot org
2003-12-31 17:31 ` pinskia at gcc dot gnu dot org
2004-01-01 13:19 ` cvs-commit at gcc dot gnu dot org
2004-01-01 13:21 ` cvs-commit at gcc dot gnu dot org
2004-01-01 15:32 ` pinskia at gcc dot gnu dot org
2004-03-03 12:54 ` ebotcazou at gcc dot gnu dot org
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