https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68911
Bug ID: 68911
Summary: wrong code at -Os and above on x86-64-linux-gnu (in
32- and 64-bit modes)
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: chengniansun at gmail dot com
Target Milestone: ---
The current gcc trunk miscompiles the following code on x86_64-linux-gnu in
both 32- and 64-bit modes at -Os and above.
$: gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-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 6.0.0 20151214 (experimental) [trunk revision 231607] (GCC)
$:
$: gcc-trunk -Os -w -m32 small.c ; timeout -s 9 10 ./a.out
Killed
$: gcc-trunk -O2 -w -m32 small.c ; timeout -s 9 10 ./a.out
Killed
$: gcc-trunk -O3 -w -m32 small.c ; timeout -s 9 10 ./a.out
Killed
$: gcc-trunk -O0 -w -m32 small.c ; timeout -s 9 10 ./a.out
$: gcc-trunk -O1 -w -m32 small.c ; timeout -s 9 10 ./a.out
$:
$: gcc-trunk -Os -w -m64 small.c ; timeout -s 9 10 ./a.out
Killed
$: gcc-trunk -O2 -w -m64 small.c ; timeout -s 9 10 ./a.out
Killed
$: gcc-trunk -O3 -w -m64 small.c ; timeout -s 9 10 ./a.out
Killed
$:
$: cat small.c
char a;
int b, c;
short d;
int main() {
unsigned e = 2;
for (; c < 2; c++) {
int f = ~e / 7;
if (f)
a = e = ~(b && d);
while (e < 94)
e++;
}
return 0;
}
$:
