Bug 205919

Summary: ICE related to std::vector<std::vector<...> > >
Product: Red Hat Enterprise Linux 4 Reporter: Hui Li <huil>
Component: gccAssignee: Jakub Jelinek <jakub>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: 4.0CC: aoliva
Target Milestone: ---   
Target Release: ---   
Hardware: i386   
OS: Linux   
Whiteboard:
Fixed In Version: RHSA-2007-0220 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-05-01 17:08:09 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
This is the preprocessed output.
none
Reduced testcase
none
Patch that fixes the bug
none
Safer patch that fixes the bug none

Description Hui Li 2006-09-10 05:30:49 UTC 
From Bugzilla Helper:
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Description of problem:
This bug seems to relate to accessing elements of a std::vector<std::vector<some_type> > > object using 
double subscripting [...][...].  However, when I tried with a simplified code, the falure didn't reproduce, so I 
guess vector of vector is just part of the reason of this bug.

Version-Release number of selected component (if applicable):
gcc version 3.4.6 20060404 (Red Hat 3.4.6-3)

How reproducible:
Always


Steps to Reproduce:
1. Just compile the proprocessed code.

Actual Results:
internal compiler error: Segmentation fault

where accessing element of std::vector<std::vector<some_type> > > using [...][...] failed.

Expected Results:


Additional info:
I found a simple work-around, i.e. to separate the [...][..] into two steps. For example, let V be of the type 
std::vector<std::vector<some_type> > >, instead of writing V[i][j], writing

const std::vector<some_type>& w = V[i];
w[j];

solved the problem.
Comment 1 Hui Li 2006-09-10 05:36:56 UTC 
Created attachment 135915 [details]
This is the preprocessed output.
Comment 2 Alexandre Oliva 2006-10-26 06:21:20 UTC 
Created attachment 139437 [details]
Reduced testcase
Comment 3 Alexandre Oliva 2006-10-26 07:09:00 UTC 
Created attachment 139441 [details]
Patch that fixes the bug

This backport fixes the ICE in both the reduced and the original testcases.  I
had to cherry-pick only a few portions of the original patch, and the most
important change (the removal of the obsolete new-type-id) isn't appropriate
for GCC 3.4 because it wasn't obsolete then.  I've tried to overcome the
problem with a simplification that I hope will work, but my testing isn't
complete yet and I'm not entirely familiar with the workings of this old
new-type-id construct.	I'd appreciate a second pair of g++-familiar eyeballs
on this change.
Comment 4 Alexandre Oliva 2006-10-27 06:36:12 UTC 
Created attachment 139556 [details]
Safer patch that fixes the bug

This patch is much safer and fixes the problem just the same.
Comment 10 Red Hat Bugzilla 2007-05-01 17:08:11 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2007-0220.html