Bug 963485 - bad code generation
bad code generation
Status: CLOSED NOTABUG
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: gcc (Show other bugs)
6.4
x86_64 Linux
unspecified Severity unspecified
: rc
: ---
Assigned To: Jakub Jelinek
qe-baseos-tools
:
Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2013-05-15 17:35 EDT by Jerry Quinn
Modified: 2013-07-18 23:17 EDT (History)
1 user (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Environment:
Last Closed: 2013-07-18 23:17:36 EDT
Type: Bug
Regression: ---
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Documentation: ---
CRM:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---


Attachments (Terms of Use)
Bug testcase (1016 bytes, text/x-c++src)
2013-05-15 17:35 EDT, Jerry Quinn
no flags Details

  None (edit)
Description Jerry Quinn 2013-05-15 17:35:21 EDT
Created attachment 748520 [details]
Bug testcase

Description of problem:

The attached code segfaults when compiled with g++ -fPIC -O3 and works at -O2.

Version-Release number of selected component (if applicable):

gcc version 4.4.7 20120313 (Red Hat 4.4.7-3) (GCC) 


How reproducible:

g++ -fPIC -O3 bad.cc
./a.out

Steps to Reproduce:
1.
2.
3.
  
Actual results:

segfault

Expected results:

terminate

Additional info:

gcc 4.7.2 compiles correctly at -O3
Comment 2 Jakub Jelinek 2013-07-18 23:17:36 EDT
The testcase is bogus.  First of all, if you run it without arguments, it will of course crash already inside of atoi.  But if you pass it argument that is not a multiple of pointer size, then the array of pointers is necessary misaligned and the testcase doesn't try to adjust it for that case (usually programs first put the aggregates that need to be aligned and only after that what doesn't need special alignment, you do it the other way around).

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