[clang] [llvm] [BPF] Do atomic_fetch_*() pattern matching with memory ordering (PR #107343)

[Ulrich Weigand via llvm-commits]

uweigand wrote:

Looks like the new test case is failing on SystemZ: https://lab.llvm.org/buildbot/#/builders/42/builds/1192
```
struct.error: unpack_from requires a buffer of at least 402653196 bytes for unpacking 12 bytes at offset 402653184 (actual buffer size is 479)
```
At first glance, this might be an endian problem (SystemZ is big-endian; 402653196 is 0x1800000c).


https://github.com/llvm/llvm-project/pull/107343