[llvm] [MemDep] Use EarliestEscapeInfo (PR #69727)

[Nikita Popov via llvm-commits]

nikic wrote:

@ZequanWu I looked at the test case, and I don't think this is a miscompile. The faulting load just gets optimized away.

The code uses the pattern
```
  int buffer0_contents = *buffer0;
  EXPECT_EQ(buffer0_contents, *buffer0);
```
which previously managed to prevent the optimization, but no longer does.

You should be able to force the load to not be optimized away by using a volatile load instead. Something like `*(volatile int *)buffer0` should do.

https://github.com/llvm/llvm-project/pull/69727