--- Comment #19 from rguenth at gcc dot gnu dot org 2006-03-17 10:33
---
*sigh*, seems like I opened a can of worms.
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rguenth at gcc dot gnu dot org changed:
What|Removed |Added
--- Comment #20 from rguenth at gcc dot gnu dot org 2006-03-17 11:03
---
For the testcase in comment #6 we fall into the
#ifdef CONSTANT_ALIGNMENT
else if (CONSTANT_CLASS_P (exp))
align = CONSTANT_ALIGNMENT (exp, align);
#endif
path and conclude the alignment is
--- Comment #21 from rguenth at gcc dot gnu dot org 2006-03-17 17:38
---
Subject: Bug 26721
Author: rguenth
Date: Fri Mar 17 17:38:51 2006
New Revision: 112177
URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=112177
Log:
2006-03-17 Richard Guenther [EMAIL PROTECTED]
PR
--- Comment #22 from rguenth at gcc dot gnu dot org 2006-03-17 17:39
---
This should be fixed now.
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rguenth at gcc dot gnu dot org changed:
What|Removed |Added
--- Comment #1 from pinskia at gcc dot gnu dot org 2006-03-16 18:42 ---
self contained testcase?
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26721
--- Comment #2 from hjl at lucon dot org 2006-03-16 18:58 ---
The testcases are in gcc testsuites. I got tens of those. Pick one from
lt-gcj-dbtool(10892):
strncpy-chk.x1(16065):
strncpy-chk.x2(16153):
strncpy-chk.x3(16260):
strncpy-chk.x4(16419):
PR9577(17600):
strncpy-chk.x2(23626):
--- Comment #3 from hjl at lucon dot org 2006-03-16 19:08 ---
It may be related to
http://gcc.gnu.org/ml/gcc-patches/2006-03/msg01001.html
http://gcc.gnu.org/ml/gcc-patches/2006-03/msg01000.html
http://gcc.gnu.org/ml/gcc-patches/2006-03/msg00999.html
--- Comment #4 from hjl at lucon dot org 2006-03-16 19:17 ---
BTW, I saw it on RHEL 4 U3.
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26721
--- Comment #5 from mkuvyrkov at gcc dot gnu dot org 2006-03-16 20:32
---
(In reply to comment #3)
It may be related to
http://gcc.gnu.org/ml/gcc-patches/2006-03/msg01001.html
http://gcc.gnu.org/ml/gcc-patches/2006-03/msg01000.html
--
pinskia at gcc dot gnu dot org changed:
What|Removed |Added
Severity|major |normal
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26721
--- Comment #6 from sje at cup dot hp dot com 2006-03-16 22:25 ---
Here is a cut down test case, I guess GCC is trying to map the strncpy into an
integer move without taking alignment into account.
extern char *strncpy (char *, const char *, __SIZE_TYPE__);
int main()
{
const char
--- Comment #7 from sje at cup dot hp dot com 2006-03-16 23:06 ---
It looks to me like this is due to Richard Guenther's patch at:
http://gcc.gnu.org/ml/gcc-patches/2006-03/msg00737.html
When I removed the non-structure part of this patch the problem went away.
specifically I changed
--- Comment #8 from pinskia at gcc dot gnu dot org 2006-03-16 23:09 ---
(In reply to comment #7)
It looks to me like this is due to Richard Guenther's patch at:
http://gcc.gnu.org/ml/gcc-patches/2006-03/msg00737.html
When I removed the non-structure part of this patch the problem
--- Comment #9 from pinskia at gcc dot gnu dot org 2006-03-16 23:10 ---
Why is ia64-linux-gnu setting STRICT_ALIGNMENT to true even though it works by
default? Yes it is slower but there is setting for that.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26721
--- Comment #10 from pinskia at gcc dot gnu dot org 2006-03-16 23:13
---
(In reply to comment #6)
Here is a cut down test case, I guess GCC is trying to map the strncpy into an
integer move without taking alignment into account.
This is all dead code, this testcase does nothing for
--- Comment #11 from sje at cup dot hp dot com 2006-03-16 23:16 ---
I compiled the test case at -O1 on IA64 HP-UX to get the bus error due to the
unaligned access. IA64 HP-UX does require STRICT_ALIGNMENT.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26721
--- Comment #12 from schwab at suse dot de 2006-03-16 23:37 ---
(In reply to comment #9)
Why is ia64-linux-gnu setting STRICT_ALIGNMENT to true even though it works by
default?
prctl --unaligned=signal will make it generate bus errors.
--
On Mar 16, 2006, at 6:37 PM, schwab at suse dot de wrote:
--- Comment #12 from schwab at suse dot de 2006-03-16 23:37
---
(In reply to comment #9)
Why is ia64-linux-gnu setting STRICT_ALIGNMENT to true even though it
works by
default?
prctl --unaligned=signal will make it
--- Comment #13 from pinskia at gcc dot gnu dot org 2006-03-16 23:54
---
Subject: Re: [4.2 Regression]: Gcc generates unaligned access
On Mar 16, 2006, at 6:37 PM, schwab at suse dot de wrote:
--- Comment #12 from schwab at suse dot de 2006-03-16 23:37
---
(In reply
--- Comment #14 from pinskia at gcc dot gnu dot org 2006-03-17 00:22
---
Now ia64-hpux is a different story.
Maybe the real question is why DSE/DCE is not deleting the dead code which it
is?
But for future reference the docs for STRICT_ALIGNMENT is:
@defmac STRICT_ALIGNMENT
Define
--- Comment #15 from schwab at suse dot de 2006-03-17 00:37 ---
Both alpha and sparc can emulate unaligned accesses, and both set
STRICT_ALIGNMENT.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26721
On Mar 16, 2006, at 7:37 PM, schwab at suse dot de wrote:
--- Comment #15 from schwab at suse dot de 2006-03-17 00:37
---
Both alpha and sparc can emulate unaligned accesses, and both set
STRICT_ALIGNMENT.
And PPC can emulate unalgined access (and does by default) and it
sets
--- Comment #16 from pinskia at gcc dot gnu dot org 2006-03-17 00:40
---
Subject: Re: [4.2 Regression]: Gcc generates unaligned access
On Mar 16, 2006, at 7:37 PM, schwab at suse dot de wrote:
--- Comment #15 from schwab at suse dot de 2006-03-17 00:37
---
Both alpha
--- Comment #17 from schwab at suse dot de 2006-03-17 01:06 ---
PPC does not trap on unaligned integer load and store. Neither ia64 nor alpha
nor sparc can do unaligned load and store in hardware.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26721
On Mar 16, 2006, at 8:06 PM, schwab at suse dot de wrote:
--- Comment #17 from schwab at suse dot de 2006-03-17 01:06
---
PPC does not trap on unaligned integer load and store.
That is not true, it traps on some. It all depends on the hardware.
Please don't say it does not trap on
--- Comment #18 from pinskia at gcc dot gnu dot org 2006-03-17 01:12
---
Subject: Re: [4.2 Regression]: Gcc generates unaligned access
On Mar 16, 2006, at 8:06 PM, schwab at suse dot de wrote:
--- Comment #17 from schwab at suse dot de 2006-03-17 01:06
---
PPC does not
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