https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107407
Bug ID: 107407
Summary: Wrong code at -Os on x86_64-linux-gnu
Product: gcc
Version: 13.0
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-tk -v
Using built-in specs.
COLLECT_GCC=gcc-tk
COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-97d1ed67fc6a5773c8c00875bfa3616a457cf5f9/libexec/gcc/x86_64-pc-linux-gnu/13.0.0/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-97d1ed67fc6a5773c8c00875bfa3616a457cf5f9
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20221024 (experimental) (GCC)
%
% gcc-tk -O0 a.c && ./a.out
3
0
0
0
% gcc-tk -Os a.c && ./a.out
0
0
0
0
% cat a.c
int printf(const char *, ...);
int *a;
static int **b = &a;
int c[4];
int d;
int e(int);
static int f(char, int);
void g() { e((f(0, 0), 0)); }
int e(int h) { *a = 0; }
int f(char k, int j) {
for (;;) {
for (; k <= 3; k++) {
*b = &c[k];
for (; d <= 1; d++)
*a = 3;
}
break;
}
}
int main() {
int i;
g();
for (i = 0; i < 4; i++)
printf("%d\n", c[i]);
}
%
Compiler explorer: https://godbolt.org/z/dTa1dvKfT
