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Bug#327351: marked as done (libc rounding is broken on HPPA)

Your message dated Mon, 06 Mar 2006 09:26:40 +0100
with message-id <440BF240.60500@aurel32.net>
and subject line Bug#327351: libc rounding is broken on HPPA
has caused the attached Bug report to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

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Debian bug tracking system administrator
(administrator, Debian Bugs database)
--- Begin Message --- 
Package: gcc-4.0
Version: 4.0.1-6
Severity: important

When compiling the fesetround function (which controls the processor
rounding mode), gcc-4.0 incorrectly optimizes away the code!!!

Here's the C code in question:
  __asm__ ("fstd %%fr0,0(%1)" : "=m" (*sw) : "r" (sw));
  sw[0] &= ~FE_DOWNWARD;
  sw[0] |= round;
  __asm__ ("fldd 0(%0),%%fr0" : : "r" (sw));

gcc-3.3 outputs:
#APP
        fstd %fr0,0(%r20)
#NO_APP
	ldw -56(%r30),%r19
	depi 0,22,2,%r19
	or %r19,%r26,%r19
	stw %r19,-56(%r30)
#APP
	fldd 0(%r20),%fr0
#NO_APP

gcc-4.0 outputs:
#APP
        fstd %fr0,0(%r28)
	fldd 0(%r28),%fr0
#NO_APP

Due to this bug, the rounding mode is broken for all clients of
libc on hppa. It's hard to judge how many applications are affected
since the failure is silent and simply results in incorrect
calculations. This may lead to any number of bugs...
		
-- System Information:
Debian Release: testing/unstable
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing')
Architecture: hppa (parisc64)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.12-1-64-smp
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)

Versions of packages gcc-4.0 depends on:
ii  binutils                      2.16.1-2   The GNU assembler, linker and bina
ii  cpp-4.0                       4.0.1-6    The GNU C preprocessor
ii  gcc-4.0-base                  4.0.1-6    The GNU Compiler Collection (base 
ii  libc6                         2.3.5-6    GNU C Library: Shared libraries an
ii  libgcc2                       4.0.1-6    GCC support library

Versions of packages gcc-4.0 recommends:
ii  libc6-dev                     2.3.5-6    GNU C Library: Development Librari
pn  libmudflap0-dev               <none>     (no description available)

-- no debconf information

--- End Message ---
--- Begin Message --- 
Carlos O'Donell a écrit :

On Wed, Mar 01, 2006 at 04:19:23PM +0100, Aurelien Jarno wrote:


On Wed, Mar 01, 2006 at 09:58:44AM -0500, Daniel Jacobowitz wrote:


On Wed, Mar 01, 2006 at 03:25:00PM +0100, Aurelien Jarno wrote:


Could we consider this bug as fixed, or is it only a postive side effect
of the patch fo bug#333766? I don't speak hppa assembly, so I can't
tell. Daniel, as you written the patch, could you please comment?


I didn't - I'm pretty sure it was Carlos's.


Ok sorry, as you introduced the patch to the Debian package, I thought
you also have written it.

Carlos, could you please comment it? Thanks.

See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=327351 for the
problem and the patch (which you probably have written).



The patch for fesetround looks good to me.


Thanks for your answer! I will close the Debian bug report then.

Bye,
Aurelien

--
  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
 : :' :  Debian GNU/Linux developer | Electrical Engineer
 `. `'   aurel32@debian.org         | aurelien@aurel32.net
   `-    people.debian.org/~aurel32 | www.aurel32.net

--- End Message ---
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