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* [Bug tree-optimization/64007] New: wrong code at -O3 on x86_64-linux-gnu
@ 2014-11-21 1:01 su at cs dot ucdavis.edu
2014-11-21 1:28 ` [Bug tree-optimization/64007] " hjl.tools at gmail dot com
0 siblings, 1 reply; 2+ messages in thread
From: su at cs dot ucdavis.edu @ 2014-11-21 1:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64007
Bug ID: 64007
Summary: wrong code at -O3 on x86_64-linux-gnu
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: su at cs dot ucdavis.edu
The current gcc trunk miscompiles the following code on x86_64-linux at -O3 in
both 32-bit and 64-bit modes.
This is a regression from 4.9.x.
$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-gnu/5.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 5.0.0 20141119 (experimental) [trunk revision 217800] (GCC)
$
$ gcc-trunk -O2 small.c; a.out
$ gcc-4.9 -O3 small.c; a.out
$
$ gcc-trunk -O3 small.c
$ ./a.out
Aborted (core dumped)
$
----------------------------
#include <assert.h>
int d, i;
struct S
{
int f0;
} *b, c, e, h, **g = &b;
static struct S *f = &e;
int
fn1 (int p)
{
int a = 0;
return a || p < 0 || p >= 2 || 1 >> p;
}
int
main ()
{
int k = 1, l, *m = &c.f0;
for (;;)
{
l = fn1 (i);
*m = k && i;
if (l)
{
int n[1] = {0};
}
break;
}
*g = &h;
assert (b);
if (d)
(*m)--;
d = (f != 0) | (i >= 0);
if (c.f0 != 0)
__builtin_abort ();
return 0;
}
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2014-11-21 1:01 [Bug tree-optimization/64007] New: wrong code at -O3 on x86_64-linux-gnu su at cs dot ucdavis.edu
2014-11-21 1:28 ` [Bug tree-optimization/64007] " hjl.tools at gmail dot com
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