https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120627
Bug ID: 120627
Summary: [15/16 regression] RISC-V: Miscompile at -O[23] since
r15-2186-g9d8ef2711df
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 sub(unsigned char t, unsigned char u) { return t - u; }
unsigned char mul(unsigned char t, unsigned char u) { return t * u; }
int x(int aa, int ab) {
return ab >= 32 || aa > 18446744073709551615UL >> ab ? aa : aa << ab;
}
int ag;
int ah = 249;
char ap;
static short ar[5][9];
int *as = &ag;
void bf(char cf) {
for (; ap <= 8; ap++) {
(ar[1][7] = mul(x(-1L, sub(cf, 247) / cf), ag <= 0)) || ar[1][4]++;
*as = ag;
}
return;
}
int main() {
bf(ah);
__builtin_printf("%d\n", ar[1][7]);
}
Commands
# -O3
> /scratch/ewlu/daily-upstream-build/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O3 ./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
# -O2
> /scratch/ewlu/daily-upstream-build/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O2 ./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
# -O1
> /scratch/ewlu/daily-upstream-build/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O1 ./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
255
Found via fuzzer
