https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110491
Bug ID: 110491
Summary: Wrong code at -O2 on x86_64-linux-gnu (a recent
regression)
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: shaohua.li at inf dot ethz.ch
Target Milestone: ---
gcc at -O2 produced wrong code.
Compiler explorer: https://godbolt.org/z/cbM1q13G7
$ cat a.c
int printf(const char *, ...);
int a, c, d, e;
short b;
void f(int *g) { c &= *g; }
void h(void);
void i() {
a = 1;
h();
f(&a);
}
void h() {
int *j = &c;
*j = 5;
k:
for (; 4 + b <= 0;)
;
for (; d;) {
c = e == 0;
goto k;
}
}
int main() {
i();
printf("%d\n", c);
}
$
$ gcc-tk -O0 a.c &&./a.out
1
$ gcc-tk -O2 a.c && ./a.out
-2003318871
$
$ gcc-tk -v
Using built-in specs.
COLLECT_GCC=gcc-tk
COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-5f590ee3174cf6058ac882c3a84a96ae639349c8/libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure --disable-multilib --disable-bootstrap
--enable-languages=c,c++
--prefix=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-5f590ee3174cf6058ac882c3a84a96ae639349c8
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20230629 (experimental) (GCC)
$
