Bug 881489 - procps compiles with -ffast-math, breaking things
Summary: procps compiles with -ffast-math, breaking things
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Fedora
Classification: Fedora
Component: procps
Version: 17
Hardware: x86_64
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Jaromír Cápík
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2012-11-29 00:43 UTC by Andy Lutomirski
Modified: 2016-02-01 01:57 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2013-07-03 22:57:23 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)

Description Andy Lutomirski 2012-11-29 00:43:37 UTC
libproc is built (and, in particular, linked) with -ffast-math.  That pulls in crtfastmath.o, which sets the flush-to-zero flag (on x86) for  which causes hilarity when you innocently link against libproc.

This is IMO so bad that I'm filing a GCC bug about it.  Fedora 18 should be unaffected because the package is completely gone.  In the mean time, please patch out the -ffast-math option.

Comment 1 Jaromír Cápík 2012-11-30 14:15:39 UTC
Hello Andy.

Could you please tell me more about those hilarities you've experienced?
Thank you.

Regards,
Jaromir.

Comment 2 Andy Lutomirski 2012-11-30 19:28:42 UTC
I have a financial program that (unsurprisingly) does math.  I added a feature that involved linking against libproc.  A while later, I noticed that floating-point math was behaving oddly.  After much cursing and modifying ld-linux to figure out what was going on, I figured out that libproc had an initializer that set the flush-to-zero and denormals-are-zero bits.  Oops.

There's nothing wrong with compiling with -ffast-math, but linking with -ffast-math is bad when you're a shared library.

Comment 3 Fedora End Of Life 2013-07-03 22:53:52 UTC
This message is a reminder that Fedora 17 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
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bug reports from releases that are no longer maintained. At that time
this bug will be closed as WONTFIX if it remains open with a Fedora 
'version' of '17'.

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Comment 4 Andy Lutomirski 2013-07-03 22:57:23 UTC
As noted, this is fixed in Fedora 18.


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