public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug tree-optimization/50599] New: -ftree-vectorize generating incorrect code
@ 2011-10-03 14:50 a5970694 at nepwk dot com
2011-10-04 11:05 ` [Bug tree-optimization/50599] " rguenth at gcc dot gnu.org
2015-10-20 9:25 ` mpolacek at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: a5970694 at nepwk dot com @ 2011-10-03 14:50 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50599
Bug #: 50599
Summary: -ftree-vectorize generating incorrect code
Classification: Unclassified
Product: gcc
Version: 4.5.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: a5970694@nepwk.com
MinGW x86 4.5.2
A loop:
while(total_out < decompressed_size)
{
printf("%X\n",p);
int chunk_size = *(int*)p;
if(chunk_size > 0)
{
int ret = params->decompressor(p+sizeof(int), chunk_size,
params->out+total_out, std::min(params->osize-total_out,params->bsize),
params->other);
int real_out = (ret / params->ssize) * params->ssize;
if(real_out != ret)
real_out += params->ssize;
if(total_out + real_out >= params->isize)
total_out += ret;
else
total_out += real_out;
p += chunk_size+sizeof(int);
}
else
{
if(params->verify)
{
memcpy(params->out+total_out, p+sizeof(int), -chunk_size);
p += -chunk_size;
}
total_out += -chunk_size;
p += sizeof(int);
}
}
Compiled with -O3 -fno-strict-aliasing works funny - the printf is called twice
with the same address. And on some data I'm getting crashes in
params->decompressor, which is a 3rd party code.
I added other printfs and I see that when running the loop for the 1st time,
the code enters the 1st branch, goes to p += chunk_size+sizeof(int), increases,
goes out of the if and iterates the loop again with unchanged p.
Adding -fno-tree-vectorize solves the problem.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/50599] -ftree-vectorize generating incorrect code
2011-10-03 14:50 [Bug tree-optimization/50599] New: -ftree-vectorize generating incorrect code a5970694 at nepwk dot com
@ 2011-10-04 11:05 ` rguenth at gcc dot gnu.org
2015-10-20 9:25 ` mpolacek at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-10-04 11:05 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50599
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |WAITING
Last reconfirmed| |2011-10-04
Ever Confirmed|0 |1
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-10-04 11:05:03 UTC ---
We need a testcase that can be at least compiled that shows the problem. Best
if it can be executed and shows the issue in runtime behavior.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/50599] -ftree-vectorize generating incorrect code
2011-10-03 14:50 [Bug tree-optimization/50599] New: -ftree-vectorize generating incorrect code a5970694 at nepwk dot com
2011-10-04 11:05 ` [Bug tree-optimization/50599] " rguenth at gcc dot gnu.org
@ 2015-10-20 9:25 ` mpolacek at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2015-10-20 9:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50599
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|WAITING |RESOLVED
CC| |mpolacek at gcc dot gnu.org
Resolution|--- |INVALID
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Test case not coming.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2015-10-20 9:25 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-10-03 14:50 [Bug tree-optimization/50599] New: -ftree-vectorize generating incorrect code a5970694 at nepwk dot com
2011-10-04 11:05 ` [Bug tree-optimization/50599] " rguenth at gcc dot gnu.org
2015-10-20 9:25 ` mpolacek at gcc dot gnu.org
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).