[llvm-bugs] [Bug 133943] [RISC-V] Miscompile on rv64gcv with -O[23]

[LLVM Bugs via llvm-bugs]

Issue	133943
Summary	[RISC-V] Miscompile on rv64gcv with -O[23]
Labels
Assignees
Reporter	ewlu

    Testcase:
```c
_Bool a;
long long q;
char f;
char g;
char k[18];
int l[18];
int main() {
 for (int i = 0; i < 18; ++i)
    k[i] = l[i] = 7;
  for (signed i = 0; i < g + 18; i += 4) {
    int o = (_Bool)(l[i] ? k[i] : f / l[i]);
    a = a < o ? a : o;
  }
  q = a;
  __builtin_printf("%llu\n", q);
}
```

Commands:
```
# riscv
$ ./bin/clang -march=rv64gcv_zvl256b -flto -O3 ./red.c -o user-config.out
$ QEMU_CPU=rv64,vlen=256,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 ./bin/qemu-riscv64 user-config.out 1
1

$ ./bin/clang -march=rv64gcv_zvl256b -flto -O2 ./red.c -o user-config.out
$ QEMU_CPU=rv64,vlen=256,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 ./bin/qemu-riscv64 user-config.out 1
1

$ ./bin/clang -march=rv64gcv_zvl256b -flto -O1 ./red.c -o user-config.out
$ QEMU_CPU=rv64,vlen=256,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 ./bin/qemu-riscv64 user-config.out 1
0

# x86
$ ./native.out
0
```

Bisected to f044564db1cbc588d0cad4f953d38f6c787dadd4 as the first bad commit

Found via fuzzer

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