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From: enrico.scholz@informatik.tu-chemnitz.de
To: gcc-gnats@gcc.gnu.org
Subject: optimization/8896: '-mcpu=xscale -fno-strict-aliasing -O2' generates wrong code
Date: Tue, 10 Dec 2002 15:46:00 -0000 [thread overview]
Message-ID: <20021210233937.23727.qmail@sources.redhat.com> (raw)
>Number: 8896
>Category: optimization
>Synopsis: '-mcpu=xscale -fno-strict-aliasing -O2' generates wrong code
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: wrong-code
>Submitter-Id: net
>Arrival-Date: Tue Dec 10 15:46:01 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Enrico Scholz
>Release: gcc-3.2.1
>Organization:
>Environment:
Reading specs from /usr/lib/gcc-lib/arm-linux/3.2.1/specs
Configured with: ../configure --host=i386-redhat-linux --target=arm-linux --prefix=/usr --mandir=/usr/share/man --disable-checking --with-cpu=strongarm1100 --enable-languages=c
Thread model: posix
gcc version 3.2.1
>Description:
The arm-linux-gcc miscompiles XScale linux-kernels (the attached testcase is derived from fs/binfmt_elf.c of linux-2.5.49 + various ARM patches).
Because of other environment-problems, I do not have a complete test-program, but the miscompilation is visible in the disassembled .o-file. The interesting code is:
---- objdump -d binfmt_elf.o
70: e3a04002 mov r4, #2 ; 0x2
7c: e0844004 add r4, r4, r4
84: e1a0e004 mov lr, r4
e0: e50be0b0 str lr, [fp, -#176]
These statements are the result of:
| 60 elf_info[ei_index++] = 3; ...
which is wrong. Other ELF-tags are incorrect too, but this is the most obvious one.
>How-To-Repeat:
Compile the testprogram with
| arm-linux-gcc -O2 -fno-strict-aliasing -mcpu=xscale -c binfmt_elf.c
Watch the output with 'objdump -d binfmt_elf.o'
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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next reply other threads:[~2002-12-10 23:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-10 15:46 enrico.scholz [this message]
2002-12-11 9:57 rearnsha
2002-12-12 7:03 rearnsha
2002-12-12 7:16 Richard Earnshaw
2002-12-16 10:06 Enrico Scholz
2003-03-22 10:05 steven
2003-03-22 13:36 Richard Earnshaw
2003-03-22 13:36 Steven Bosscher
2003-03-22 13:54 steven
2003-05-14 17:46 Dara Hazeghi
2003-05-15 18:46 Daniel Jacobowitz
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