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* [Bug optimization/1823] -ftrapv aborts with pointer difference due to division optimization
[not found] <20010131120600.1823.meeberdt@unity.ncsu.edu>
@ 2003-07-06 17:09 ` falk at debian dot org
2003-07-06 17:27 ` falk at debian dot org
` (4 subsequent siblings)
5 siblings, 0 replies; 6+ messages in thread
From: falk at debian dot org @ 2003-07-06 17:09 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=1823
falk at debian dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|CLOSED |REOPENED
Component|libstdc++ |optimization
Resolution|FIXED |
Summary|program compiled with - |-ftrapv aborts with pointer
|ftrapv aborts in |difference due to division
|std::queue<>.size() |optimization
Version|3.0 |3.4
------- Additional Comments From falk at debian dot org 2003-07-06 17:09 -------
Here's a test case (works for me on alpha-linux mainline):
struct s { char c[3]; };
__PTRDIFF_TYPE__ frob (struct s *cur, struct s *last) {
return last - cur;
}
int main (void) {
struct s a[17];
if (frob(a, a + 17) != 17)
abort ();
return 0;
}
The problem is caused by the optimization of the division by three to a
multiplication with 0xaaaaaaaaaaaaaaab; this works since the difference
is known to be a multiple of 3.
However, the multiplication is done with a trapping instruction:
subq/v a1,a0,t2
ldq t3,32256(t0) # 0xaaaaaaaaaaaaaaab
mulq/v t2,t3,v0 # traps
ret
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug optimization/1823] -ftrapv aborts with pointer difference due to division optimization
[not found] <20010131120600.1823.meeberdt@unity.ncsu.edu>
2003-07-06 17:09 ` [Bug optimization/1823] -ftrapv aborts with pointer difference due to division optimization falk at debian dot org
@ 2003-07-06 17:27 ` falk at debian dot org
2003-07-06 17:30 ` falk at debian dot org
` (3 subsequent siblings)
5 siblings, 0 replies; 6+ messages in thread
From: falk at debian dot org @ 2003-07-06 17:27 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=1823
falk at debian dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |169862 at bugs dot debian
| |dot org
------- Additional Comments From falk at debian dot org 2003-07-06 17:27 -------
*** Bug 9067 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug optimization/1823] -ftrapv aborts with pointer difference due to division optimization
[not found] <20010131120600.1823.meeberdt@unity.ncsu.edu>
2003-07-06 17:09 ` [Bug optimization/1823] -ftrapv aborts with pointer difference due to division optimization falk at debian dot org
2003-07-06 17:27 ` falk at debian dot org
@ 2003-07-06 17:30 ` falk at debian dot org
2003-09-05 18:28 ` cvs-commit at gcc dot gnu dot org
` (2 subsequent siblings)
5 siblings, 0 replies; 6+ messages in thread
From: falk at debian dot org @ 2003-07-06 17:30 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=1823
falk at debian dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |wefing at gmx dot de
------- Additional Comments From falk at debian dot org 2003-07-06 17:30 -------
*** Bug 9088 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug optimization/1823] -ftrapv aborts with pointer difference due to division optimization
[not found] <20010131120600.1823.meeberdt@unity.ncsu.edu>
` (2 preceding siblings ...)
2003-07-06 17:30 ` falk at debian dot org
@ 2003-09-05 18:28 ` cvs-commit at gcc dot gnu dot org
2003-09-06 1:31 ` roger at eyesopen dot com
2003-10-17 17:48 ` pinskia at gcc dot gnu dot org
5 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu dot org @ 2003-09-05 18:28 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=1823
------- Additional Comments From cvs-commit at gcc dot gnu dot org 2003-09-05 18:28 -------
Subject: Bug 1823
CVSROOT: /cvs/gcc
Module name: gcc
Changes by: sayle@gcc.gnu.org 2003-09-05 18:28:48
Modified files:
gcc : ChangeLog expmed.c
Log message:
PR optimization/1823
* expmed.c (expand_divmod <EXACT_DIV_EXPR>): Use an unsigned
multiplication to implement division by constant integer.
Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.980&r2=2.981
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/expmed.c.diff?cvsroot=gcc&r1=1.140&r2=1.141
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug optimization/1823] -ftrapv aborts with pointer difference due to division optimization
[not found] <20010131120600.1823.meeberdt@unity.ncsu.edu>
` (3 preceding siblings ...)
2003-09-05 18:28 ` cvs-commit at gcc dot gnu dot org
@ 2003-09-06 1:31 ` roger at eyesopen dot com
2003-10-17 17:48 ` pinskia at gcc dot gnu dot org
5 siblings, 0 replies; 6+ messages in thread
From: roger at eyesopen dot com @ 2003-09-06 1:31 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=1823
roger at eyesopen dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|REOPENED |RESOLVED
Resolution| |FIXED
------- Additional Comments From roger at eyesopen dot com 2003-09-06 01:31 -------
This has now been fixed on mainline.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug optimization/1823] -ftrapv aborts with pointer difference due to division optimization
[not found] <20010131120600.1823.meeberdt@unity.ncsu.edu>
` (4 preceding siblings ...)
2003-09-06 1:31 ` roger at eyesopen dot com
@ 2003-10-17 17:48 ` pinskia at gcc dot gnu dot org
5 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2003-10-17 17:48 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=1823
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |3.4
^ permalink raw reply [flat|nested] 6+ messages in thread
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[not found] <20010131120600.1823.meeberdt@unity.ncsu.edu>
2003-07-06 17:09 ` [Bug optimization/1823] -ftrapv aborts with pointer difference due to division optimization falk at debian dot org
2003-07-06 17:27 ` falk at debian dot org
2003-07-06 17:30 ` falk at debian dot org
2003-09-05 18:28 ` cvs-commit at gcc dot gnu dot org
2003-09-06 1:31 ` roger at eyesopen dot com
2003-10-17 17:48 ` pinskia at gcc dot gnu dot org
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