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[Bug middle-end/33638] optimization bug: wrong code with -fforce-addr
- From: "manfred99 at gmx dot ch" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 3 Oct 2007 20:10:52 -0000
- Subject: [Bug middle-end/33638] optimization bug: wrong code with -fforce-addr
- References: <bug-33638-9562@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #5 from manfred99 at gmx dot ch 2007-10-03 20:10 -------
Subject: Re: optimization bug: wrong code with
-fforce-addr
> ------- Comment #4 from ubizjak at gmail dot com 2007-10-03 15:43 -------
> Please provide enough sources to create an _executable_ that shows the
> failure.
> We are dealing with runtime failure here.
>
If I could come up with a short testcase just like that,
I would have done so already.
> A _short_ testcase (<30 lines) is nice to have, so all non-related parts
> should
> be removed. Wandering through a maze of jumps certainly doesn't help to
> find
> the problem.
>
> An abort() should be called for wrong result, but at least wrong result
> and
> expected result should be described to help trace the issue down.
>
I will see what I can do, but do not expect any miracles.
This is from a large software package with ~10^2 functions
and at the end there is a binary output file of several MB which is
either as it should or not :-(
And as I told in the bug report, inserting or deleting code suddenly
let the issue vanish. I already tried to reduce this code with the
result that removing dead code fixed the miscompilation.
> BTW: Assembler dumps are not _that_ informative, especially without
> -fverbose-asm ;)
>
As it was not clear to me what information to provide, I asked first
on the gcc mailing list, to no avail, so I provided just some random
information.
BTW 1:
# gfortran -v
Using built-in specs.
Target: i386-pc-linux-gnu
Configured with: /home/fx/gfortran_nightbuild/trunk/configure
--prefix=/home/fx/gfortran_nightbuild/irun-20071001
--enable-languages=c,fortran --build=i386-pc-linux-gnu
--enable-checking=release --with-gmp=/home/fx/gfortran_nightbuild/software
Thread model: posix
gcc version 4.3.0 20071001 (experimental) [trunk revision 128899] (GCC)
BTW 2:
Code was checked with valgrind and efence, seems to be ok.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33638