https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120044
Bug ID: 120044
Summary: wrong code at -O1 and above with "-fno-early-inlining
-fno-tree-fre -fno-tree-pre -fno-code-hoisting" on
x86_64-linux-gnu
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: zhendong.su at inf dot ethz.ch
Target Milestone: ---
Compiler Explorer: https://godbolt.org/z/jK8rG558r
It appears to be a latent issue and affects 12.1 and later.
[535] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/16.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--enable-checking=yes --prefix=/local/suz-local/software/local/gcc-trunk
--enable-sanitizers --enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 16.0.0 20250430 (experimental) (GCC)
[536] %
[536] % gcctk -O3 small.c; ./a.out
[537] %
[537] % gcctk -O3 -fno-early-inlining -fno-tree-fre -fno-tree-pre
-fno-code-hoisting small.c
[538] % ./a.out
Segmentation fault
[539] %
[539] % cat small.c
struct a {
int b;
} const c;
void d(char p, struct a e) {
while (e.b)
;
}
static unsigned short f(const struct a g) {
d(g.b, g);
return g.b;
}
int main() { f(c); }
