This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/69951] New: wrong code at -O1 and above on x86_64-linux-gnu
- From: "helloqirun at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 25 Feb 2016 01:25:14 +0000
- Subject: [Bug tree-optimization/69951] New: wrong code at -O1 and above on x86_64-linux-gnu
- Auto-submitted: auto-generated
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69951
Bug ID: 69951
Summary: wrong code at -O1 and above on x86_64-linux-gnu
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: helloqirun at gmail dot com
Target Milestone: ---
The current gcc trunk mis-compiles the following code on x86_64-linux-gnu at
-O1 and above in both 32-bit and 64-bit modes.
It affects as early as gcc-4.4.3 (I don't have earlier gcc on my machine).
$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/home/absozero/trunk/root-gcc/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --prefix=/home/absozero/trunk/root-gcc
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 6.0.0 20160224 (experimental) [trunk revision 233678] (GCC)
$ gcc-trunk abc.c
$ ./a.out
$ gcc-trunk -O1 abc.c
$ ./a.out
Aborted (core dumped)
$ cat abc.c
int a = 1, c = 1;
extern int b __attribute__((alias("a")));
extern int d __attribute__((alias("c")));
int main(int argc) {
int *p, *q;
if (argc)
p = &c, q = &d;
else
p = &b, q = &d;
*p = 1;
*q = 2;
if (*p == 1)
__builtin_abort();
return 0;
}