Red Hat Bugzilla – Bug 593117
gcc44 -O issue Xor instructions optimized out.
Last modified: 2011-05-13 08:57:55 EDT
All Issues: Problem Description
1. Time and date of problem:
2. System architecture(s):
RHEL 5.4, x86_64 gcc44
3. Provide a clear and concise problem description as it is understood at the
time of escalation. Please be as specific as possible in your description.
Do not use the generic term "hang", as that can mean many things.
Using the attached reproducer (markh_bug.c) we see the following:
$ gcc44 -O -o rehl5.5_gcc_O1 markh_bug.c
ff7f0000 ff7f0000 ff7f0000 - FAIL
That this test case work with gcc44 and level 1 optimization:
$ gcc44 -O2 -o rehl5.5_gcc_O2 markh_bug.c
05020300 09060704 0d0a0b08 - OK
4. Specific action requested of SEG:
Please help me to identify the fix that went into later versions of gcc (gcc 4.4.3 from Fedora 12) to back port to RHEL 5.
5. Is a defect (bug) in the product suspected? yes
6. Does a proposed patch exist? yes and no
Since this seems to be fixed in Fedora 12 (gcc 4.4.3) I'm sure a patch exists somewhere, but I don't know which one.
7. What is the impact to the customer when they experience this problem?
Customer is continuing their work on porting their applications to gcc 44 to be ready for RHEL 6.
As mentioned above I have verified that this issue does not happen on Fedora 12 with both gcc 4.4.2 and 4.4.3. The fix is out there, but I'm afraid I don't know which one it is.
The Xor instructions are being optimized out at -O1.
I thought that it was BZ 40087 but that doesn't seem to be the case.
Created attachment 414667 [details]
Why do you need to know which patch was it? If gcc44 is ever errataed again in RHEL 5, it would be updated to current RHEL6 gcc. Nothing else makes any sense.
I don't. I forgot to remove that comment.
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 therefore 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.