[llvm] [LLVM] Relax clobbering checks for calls to consider writes only (PR #179721)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

Here is a test case for `print<memory-ssa>`:
```llvm
declare void @fn(ptr %p)

define void @foo(ptr %p) {
  call void @fn(ptr %p) memory(argmem: read, inaccessiblemem: readwrite)
  call void @fn(ptr %p) memory(argmem: read)
  ret void
}
```
Without this patch it will print `MemoryUse(1)`, with the patch `MemoryUse(liveOnEntry)`.

https://github.com/llvm/llvm-project/pull/179721