https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116085
Bug ID: 116085
Summary: RISC-V: Miscompile at -O2 with zbb
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: patrick at rivosinc dot com
Target Milestone: ---
There may be a way to show the bug using a single file but I hadn't had success
in merging them yet.
Testcase:
driver.c:
int a = 2;
unsigned b = 0x80000000;
int arr_5[2][23];
void test(int, unsigned, int);
int main() {
test(a, b, 1);
__builtin_printf("%d\n", arr_5[1][0]);
}
func.c:
extern int arr_5[2][23];
#define c(a, b)
\
({
\
long d = a;
\
long e = b;
\
d > e ? d : e;
\
})
void test(int f, unsigned g, int h) {
for (int i = 0; i < h; i = f)
arr_5[1][i] = h ? c(g, 7) : 0;
}
Commands:
> /scratch/tc-testing/tc-compiler-fuzz-trunk/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -march=rv64id_zbb -O2 -c func.c -o func.o
> /scratch/tc-testing/tc-compiler-fuzz-trunk/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -c driver.c -o driver.o
> /scratch/tc-testing/tc-compiler-fuzz-trunk/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> func.o driver.o -o user-config.out
> 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,zbb=true
> timeout --verbose -k 0.1 4
> /scratch/tc-testing/tc-compiler-fuzz-trunk/build-gcv/bin/qemu-riscv64
> user-config.out
7
> /scratch/tc-testing/tc-compiler-fuzz-trunk/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -O2 -c func.c -o func.o
> /scratch/tc-testing/tc-compiler-fuzz-trunk/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> -c driver.c -o driver.o
> /scratch/tc-testing/tc-compiler-fuzz-trunk/build-gcv/bin/riscv64-unknown-linux-gnu-gcc
> func.o driver.o -o user-config.out
> 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,zbb=true
> timeout --verbose -k 0.1 4
> /scratch/tc-testing/tc-compiler-fuzz-trunk/build-gcv/bin/qemu-riscv64
> user-config.out
-2147483648
Found via fuzzer.
