https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117226
Bug ID: 117226
Summary: wrong code at -O{s,2,3} with "-fno-tree-forwprop" 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 recent regression as it doesn't reproduce with 14.2 and
earlier.
Compiler Explorer: https://godbolt.org/z/ahrsqb8Tf
[518] % 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 20241019 (experimental) (GCC)
[519] %
[519] % gcctk -O3 small.c; ./a.out
[520] %
[520] % gcctk -O3 -fno-tree-forwprop small.c
[521] % ./a.out
Aborted
[522] %
[522] % cat small.c
int a = 128, b, d;
long e = -2, c;
int main() {
char f = a;
int g = f;
c = (g < 0) - e;
unsigned char h = g;
b = h % c;
d = 9000000000000 << b;
if (d > 1)
__builtin_abort();
return 0;
}
