https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115467
Bug ID: 115467
Summary: wrong code at -O1 with "-fno-tree-fre" 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: ---
It appears to be a regression from 11.* and affects 12.* and later.
Compiler Explorer: https://godbolt.org/z/o5PMfan4v
[530] % 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/15.0.0/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 15.0.0 20240612 (experimental) (GCC)
[531] %
[531] % gcctk -O1 small.c; ./a.out
[532] %
[532] % gcctk -O1 -fno-tree-fre small.c
[533] % ./a.out
Segmentation fault
[534] %
[534] % cat small.c
struct a {
int b;
} const c;
int d;
void e(const struct a p, int q) { d = 0; }
void f(const struct a g) {
e(g, g.b);
g.b ^ d;
}
int main() {
f(c);
return 0;
}
