https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120736
Bug ID: 120736
Summary: [16 Regression] RISC-V: Miscompile at -O[23] since
r15-5375-gbeec291225b
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: ewlu at rivosinc dot com
Target Milestone: ---
Testcase:
unsigned char aa (unsigned char ab, int o) { return ab > o ? ab : 0; }
int p;
int s;
static unsigned char q = 255;
int r;
int *v = &s;
int main() {
p = v != 0;
for (; r < 8; ++r) {
if (s)
break;
s = aa(p * q++, 6) <= 0;
}
__builtin_printf("%d\n", q);
}
Commands:
# -O3
> /scratch/ewlu/daily-upstream-build/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O3 ./runtime-bisect/red.c -o user-config.out -fsigned-char
> -fno-strict-aliasing -fwrapv
> QEMU_CPU=rv64,vlen=128,rvv_ta_all_1s=true,rvv_ma_all_1s=true,v=true,vext_spec=v1.0,zve32f=true,zve64f=true
> timeout --verbose -k 0.1 4
> /scratch/ewlu/daily-upstream-build/build-gcv/bin/qemu-riscv64 user-config.out
> 1
7
# -O2
> /scratch/ewlu/daily-upstream-build/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O2 ./runtime-bisect/red.c -o user-config.out -fsigned-char
> -fno-strict-aliasing -fwrapv
> QEMU_CPU=rv64,vlen=128,rvv_ta_all_1s=true,rvv_ma_all_1s=true,v=true,vext_spec=v1.0,zve32f=true,zve64f=true
> timeout --verbose -k 0.1 4
> /scratch/ewlu/daily-upstream-build/build-gcv/bin/qemu-riscv64 user-config.out
> 1
7
# -O1
> /scratch/ewlu/daily-upstream-build/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O1 ./runtime-bisect/red.c -o user-config.out -fsigned-char
> -fno-strict-aliasing -fwrapv
> QEMU_CPU=rv64,vlen=128,rvv_ta_all_1s=true,rvv_ma_all_1s=true,v=true,vext_spec=v1.0,zve32f=true,zve64f=true
> timeout --verbose -k 0.1 4
> /scratch/ewlu/daily-upstream-build/build-gcv/bin/qemu-riscv64 user-config.out
> 1
1
Found via fuzzer
