Re: [arm-gnu] Compiler bug using GCC 4.x.x

[Mark Mitchell <mark@xxxxxxxxxxxxxxxx>]

Remy Bohmer wrote:

> I am using gcc version 4.2.3 (Sourcery G++ Lite 2008q1-126) and I have
> discovered a compiler bug which seems to be related to '__attribute__
> ((packed))' and the code optimiser of GCC 4.x.x.
> 
> The resulting object code uses register 'r3' as loop counter for the
> variable 'i' in the routine usb_set_maxpacket().
> BUT: This register is used later on for other purposes, resulting in a
> corrupt loop counter 'i'.

That certainly sounds like a bug, though we'd have to confirm that, of
course.  Of course, once we know it's a bug, we'll have to track it
down; it could be a bug in the ARM back end, or in some other part of
the compiler.

> Any idea how to get this bug fixed in future versions of GCC?

You've taken the first step: reporting it to us.  You could also report
it to the bug-tracker at gcc.gnu.org.

We do try to look into bug reports like this, but our first priority is
of course our customers, so issues they raise get attended to first.
(Of course, you're welcome to become a Professional Edition customer; we
do try to respond quite quickly, including putting new compilers in the
field as necessary, for such customers.)

We'll also have our Fall 2008 release out in October.  That will be
based on GCC 4.3.x.

Thanks,

-- 
Mark Mitchell
CodeSourcery
mark@xxxxxxxxxxxxxxxx
(650) 331-3385 x713