| Issue |
80910
|
| Summary |
RISCV64 vector miscompile at -O2
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
patrick-rivos
|
Testcase:
```c
int printf(const char *, ...);
int b, e, z, v, h;
short i, j;
int *k = &b;
static int l;
static int *n = &l;
static int o;
static int r() {
long x = 0;
signed char y = 0;
short w = 0;
*k = 1;
h = 0;
n;
while (h < 2) {
e = i = 0;
while (i < 3) {
j = o << l;
w = b * 3;
e ^= j >= 0;
long q = e;
x = w & -q ?: w;
y = x;
z |= y;
while (o < 2)
o += 1;
i += 1;
}
h++;
}
return z;
}
int main() {
v = r();
printf("%d\n", v);
}
```
Commands:
```bash
> /scratch/tc-testing/llvm-feb-5/build/bin/clang -O2 -march=rv64gcv red.c -o user-config.out -Wno-unused-value
> QEMU_CPU=rv64,Zve32f=true,Zve64f=true /scratch/tc-testing/llvm-feb-5/build/bin/qemu-riscv64 user-config.out
0
> /scratch/tc-testing/llvm-feb-5/build/bin/clang -O1 -march=rv64gcv red.c -o user-config.out -Wno-unused-value
> QEMU_CPU=rv64,Zve32f=true,Zve64f=true /scratch/tc-testing/llvm-feb-5/build/bin/qemu-riscv64 user-config.out
3
```
.c, .bc, .asm:
[c-bc-asm.zip](https://github.com/llvm/llvm-project/files/14186745/c-bc-asm.zip)
`--opt-bisect-limit` points to `InstCombinePass`
Discovered/tested using a7bc9cb6ffa91ff0ebabc45c0c7263c7c2c3a4de (not bisected)
Found using fuzzer.
#80792 also fails with `-march=rv64gcv -O2` so these might be related?
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