| Issue |
176001
|
| Summary |
[RISCV] Wrong code at -O1 on riscv64-unknown-linux-musl
|
| Labels |
backend:RISC-V,
miscompilation,
generated by fuzzer
|
| Assignees |
|
| Reporter |
XChy
|
Reduced C testcase:
```c
#include <stdio.h>
#include <riscv_bitmanip.h>
#define BS_VEC(type, num) type __attribute__((vector_size(num * sizeof(type))))
#define BARRIER_u8(x) (uint8_t)(__riscv_orc_b_32(1) + x - 0xff)
#define BARRIER_u64(x) (uint64_t)(__riscv_orc_b_64(1) + x - 0xffull)
#define BARRIER_v4u32(x) (__riscv_orc_b_32(0) ? (BS_VEC(uint32_t, 4)){} : x)
#define BARRIER_v16u8(x) (__riscv_orc_b_32(0) ? (BS_VEC(uint8_t, 16)){} : x)
// BARRIER_xxxx(x) should be equivalent to x.
int main()
{
uint32_t volatile BS_COND_0 = 9002699;
switch (BS_COND_0)
{
case 3: goto BS_LABEL_5;
case 4: goto BS_LABEL_8;
}
BS_VEC(uint64_t, 32) BS_VAR_1[52] = {};
BS_LABEL_9:
if (BARRIER_u8(0)) goto BS_LABEL_8;
uint64_t LOCAL_CHECKSUM = 0;
BS_LABEL_7:
uint16_t l_7 = 35;
BS_LABEL_5:
int volatile BS_COND_2 = 0;
if (BS_COND_2) goto BS_LABEL_9;
uint8_t BS_TEMP_239 = BARRIER_u64(0);
BS_VEC(uint64_t, 32)
BS_TEMP_240 = { BS_TEMP_239, BS_TEMP_239, BS_TEMP_239, BS_TEMP_239,
BS_TEMP_239, BS_TEMP_239, BS_TEMP_239, BS_TEMP_239,
BS_TEMP_239, BS_TEMP_239, BS_TEMP_239, BS_TEMP_239,
BS_TEMP_239, BS_TEMP_239, BS_TEMP_239, BS_TEMP_239,
BS_TEMP_239, BS_TEMP_239, BS_TEMP_239, BS_TEMP_239,
BS_TEMP_239, BS_TEMP_239, BS_TEMP_239, BS_TEMP_239,
BS_TEMP_239, BS_TEMP_239, BS_TEMP_239, BS_TEMP_239,
BS_TEMP_239, BS_TEMP_239, BS_TEMP_239, BS_TEMP_239 };
BS_LABEL_8:
BS_VEC(uint64_t, 32) BS_TEMP_241 = BS_VAR_1[2];
BS_VEC(uint64_t, 32)
BS_TEMP_242 = __builtin_convertvector(
__builtin_shufflevector((BS_VEC(uint8_t, 16)){},
BARRIER_v16u8((BS_VEC(uint8_t, 16)){ 66 }), 2,
0, 5, 7, 0, 1, 8, 7, 4, 3, 0, 4, 2, 8, 9, 4, 0,
0, 2, 0, 9, 20, 4, 2, 16, 6, 8, 4, 5, 4, 5, 5),
BS_VEC(uint64_t, 32));
BS_VAR_1[0] =
__builtin_convertvector(
__builtin_shufflevector(
BARRIER_v4u32(((BS_VEC(uint32_t, 4)){ 35, 0, l_7, 0 })),
(BS_VEC(uint32_t, 4)){ 0, 0, 0, 35 }, 0, 4, 4, 0, 7, 2, 6, 0, 0,
5, 6, 6, 7, 0, 3, 7, 2, 6, 7, 6, 4, 0, 3, 4, 0, 3, 5, 0, 4, 7,
0, 4),
BS_VEC(uint64_t, 32))
<= (BS_VEC(uint64_t, 32)){
BS_TEMP_240[0],
0,
0,
BS_TEMP_241[3] ? BS_TEMP_240[3] << 3 : BS_TEMP_242[3],
0,
0,
0,
0,
0,
BS_TEMP_241[9] ? BS_TEMP_240[9] << 9 : BS_TEMP_242[9],
0,
0,
0,
BS_TEMP_240[3],
0,
5,
BS_TEMP_242[16],
0,
BS_TEMP_241[18] < 4 ? BS_TEMP_240[8] << 8 : BS_TEMP_242[18],
BS_TEMP_241[19],
BS_TEMP_240[0],
BS_TEMP_240[21] << BS_TEMP_241[21],
BS_TEMP_240[22],
BS_TEMP_240[3],
BS_TEMP_240[24],
BS_TEMP_240[25],
BS_TEMP_240[6],
BS_TEMP_240[7],
BS_TEMP_241[28],
BS_TEMP_240[9],
BS_TEMP_240[0],
1 << BS_TEMP_241[1]
};
uint32_t volatile BS_COND_4 = 5;
if (BS_COND_4 == 7) goto BS_LABEL_7;
for (uint32_t BS_TEMP_243 = 0; BS_TEMP_243 < 2; BS_TEMP_243++)
LOCAL_CHECKSUM ^= BS_VAR_1[BS_TEMP_243][21];
uint64_t BS_CHECKSUM = LOCAL_CHECKSUM;
printf("BackSmith Checksum = 0x%016llx\n", BS_CHECKSUM);
}
```
Reproducible commands:
qemu-riscv64 version 10.1.2
```bash
> clang --target=riscv64-unknown-linux-musl -march=rv64gcvb_zicond --gcc-toolchain=<toolchain> --sysroot=<sysroot> -static -O0 a.c
> qemu-riscv64 a.out
BackSmith Checksum = 0xffffffffffffffff
> clang --target=riscv64-unknown-linux-musl -march=rv64gcvb_zicond --gcc-toolchain=<toolchain> --sysroot=<sysroot> -static -O1 a.c
> qemu-riscv64 a.out
BackSmith Checksum = 0x0000000000000000
```
Undefined behaviour check (replace BARRIER_xxx(x) with x): https://godbolt.org/z/fbWxeE8x4
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