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* [Bug tree-optimization/63380] New: Wrong constant folding
@ 2014-09-26 9:45 ishiura-compiler at ml dot kwansei.ac.jp
2014-10-02 15:01 ` [Bug tree-optimization/63380] [5 Regression] " mpolacek at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: ishiura-compiler at ml dot kwansei.ac.jp @ 2014-09-26 9:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63380
Bug ID: 63380
Summary: Wrong constant folding
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 5.0.0 for x86_64 miscompiles the following code.
$ cat test.c
int a = 0, b = 1, c = 0, d = 1, e, f, g, h;
int
main ()
{
e = 1 >> d;
f = ((31 / (1 > e)) || c) / 2;
g = b || a;
h = 31 / g;
if (!h)
__builtin_abort();
return 0;
}
$ x86_64-unknown-linux-gnu-gcc-5.0.0 test.c -O2
$ ./a.out
Floating point exception (core dumped)
$ x86_64-unknown-linux-gnu-gcc-5.0.0 -v
Using built-in specs.
COLLECT_GCC=x86_64-unknown-linux-gnu-gcc-5.0.0
COLLECT_LTO_WRAPPER=/usr/local/x86_64-tools/gcc-
5.0.0/libexec/gcc/x86_64-unknown-linux-gnu/5.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /home/orange3/gcc-master/configure --
prefix=/usr/local/x86_64-tools/gcc-5.0.0/ --with-gmp=/usr/local/gmp-
5.1.1/ --with-mpfr=/usr/local/mpfr-3.1.2/ --with-mpc=/usr/local/mpc-
1.0.1/ --disable-multilib --disable-nls --enable-languages=c
Thread model: posix
gcc version 5.0.0 20140922 (experimental) (GCC)
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/63380] [5 Regression] Wrong constant folding
2014-09-26 9:45 [Bug tree-optimization/63380] New: Wrong constant folding ishiura-compiler at ml dot kwansei.ac.jp
@ 2014-10-02 15:01 ` mpolacek at gcc dot gnu.org
2014-10-06 12:05 ` rguenth at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2014-10-02 15:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63380
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2014-10-02
CC| |mpolacek at gcc dot gnu.org
Target Milestone|--- |5.0
Summary|Wrong constant folding |[5 Regression] Wrong
| |constant folding
Ever confirmed|0 |1
--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Works with -fno-tree-vrp. Seems to have started with r211904.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/63380] [5 Regression] Wrong constant folding
2014-09-26 9:45 [Bug tree-optimization/63380] New: Wrong constant folding ishiura-compiler at ml dot kwansei.ac.jp
2014-10-02 15:01 ` [Bug tree-optimization/63380] [5 Regression] " mpolacek at gcc dot gnu.org
@ 2014-10-06 12:05 ` rguenth at gcc dot gnu.org
2014-10-08 14:58 ` rguenth at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-10-06 12:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63380
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Mine.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/63380] [5 Regression] Wrong constant folding
2014-09-26 9:45 [Bug tree-optimization/63380] New: Wrong constant folding ishiura-compiler at ml dot kwansei.ac.jp
2014-10-02 15:01 ` [Bug tree-optimization/63380] [5 Regression] " mpolacek at gcc dot gnu.org
2014-10-06 12:05 ` rguenth at gcc dot gnu.org
@ 2014-10-08 14:58 ` rguenth at gcc dot gnu.org
2014-10-09 8:18 ` rguenth at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-10-08 14:58 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63380
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Hmm. We end up with
main ()
{
int d.0_4;
int e.1_5;
int _7;
int b.7_11;
int a.8_12;
<bb 2>:
d.0_4 = d;
e.1_5 = 1 >> d.0_4;
e = e.1_5;
_7 = 31 / 0;
in the end. Which is caused by tail-merging (part of PRE) optimizing
<bb 2>:
d.0_4 = d;
e.1_5 = 1 >> d.0_4;
e = e.1_5;
if (e.1_5 <= 0)
goto <bb 10>;
else
goto <bb 3>;
<bb 10>:
goto <bb 4>;
<bb 3>:
_7 = 31 / 0;
<bb 4>:
by removing bb 3 as having no side-effect appearantly (_7 is unused). It
produces
<bb 2>:
d.0_4 = d;
e.1_5 = 1 >> d.0_4;
e = e.1_5;
<bb 3>:
_7 = 31 / 0;
<bb 4>:
not sure how it ends up doing that (I suppose it has code to merge an
if diamond).
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/63380] [5 Regression] Wrong constant folding
2014-09-26 9:45 [Bug tree-optimization/63380] New: Wrong constant folding ishiura-compiler at ml dot kwansei.ac.jp
` (2 preceding siblings ...)
2014-10-08 14:58 ` rguenth at gcc dot gnu.org
@ 2014-10-09 8:18 ` rguenth at gcc dot gnu.org
2014-10-09 12:45 ` rguenth at gcc dot gnu.org
2014-10-10 11:06 ` rguenth at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-10-09 8:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63380
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
*** Bug 63381 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/63380] [5 Regression] Wrong constant folding
2014-09-26 9:45 [Bug tree-optimization/63380] New: Wrong constant folding ishiura-compiler at ml dot kwansei.ac.jp
` (3 preceding siblings ...)
2014-10-09 8:18 ` rguenth at gcc dot gnu.org
@ 2014-10-09 12:45 ` rguenth at gcc dot gnu.org
2014-10-10 11:06 ` rguenth at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-10-09 12:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63380
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Thu Oct 9 12:45:07 2014
New Revision: 216038
URL: https://gcc.gnu.org/viewcvs?rev=216038&root=gcc&view=rev
Log:
2014-10-09 Richard Biener <rguenther@suse.de>
PR tree-optimization/63380
* tree-ssa-tail-merge.c (stmt_local_def): Exclude stmts that
may trap.
* gcc.dg/torture/pr63380-1.c: New testcase.
* gcc.dg/torture/pr63380-2.c: Likewise.
Added:
trunk/gcc/testsuite/gcc.dg/torture/pr63380-1.c
trunk/gcc/testsuite/gcc.dg/torture/pr63380-2.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/testsuite/ChangeLog
trunk/gcc/tree-ssa-tail-merge.c
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/63380] [5 Regression] Wrong constant folding
2014-09-26 9:45 [Bug tree-optimization/63380] New: Wrong constant folding ishiura-compiler at ml dot kwansei.ac.jp
` (4 preceding siblings ...)
2014-10-09 12:45 ` rguenth at gcc dot gnu.org
@ 2014-10-10 11:06 ` rguenth at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-10-10 11:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63380
--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Oct 10 11:05:39 2014
New Revision: 216066
URL: https://gcc.gnu.org/viewcvs?rev=216066&root=gcc&view=rev
Log:
2014-10-10 Richard Biener <rguenther@suse.de>
PR tree-optimization/63380
* tree-ssa-tail-merge.c (stmt_local_def): Exclude stmts that
may trap.
* gcc.dg/torture/pr63380-1.c: New testcase.
* gcc.dg/torture/pr63380-2.c: Likewise.
Added:
branches/gcc-4_9-branch/gcc/testsuite/gcc.dg/torture/pr63380-1.c
branches/gcc-4_9-branch/gcc/testsuite/gcc.dg/torture/pr63380-2.c
Modified:
branches/gcc-4_9-branch/gcc/ChangeLog
branches/gcc-4_9-branch/gcc/testsuite/ChangeLog
branches/gcc-4_9-branch/gcc/tree-ssa-tail-merge.c
^ permalink raw reply [flat|nested] 7+ messages in thread
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2014-09-26 9:45 [Bug tree-optimization/63380] New: Wrong constant folding ishiura-compiler at ml dot kwansei.ac.jp
2014-10-02 15:01 ` [Bug tree-optimization/63380] [5 Regression] " mpolacek at gcc dot gnu.org
2014-10-06 12:05 ` rguenth at gcc dot gnu.org
2014-10-08 14:58 ` rguenth at gcc dot gnu.org
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2014-10-09 12:45 ` rguenth at gcc dot gnu.org
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