When LOps.RootInsert comes after LI2, since we use LI2 as the new insert
point, we should make sure the memory region accessed by LOps isn't
modified. However, the original implementation passes the bit width
`LOps.LoadSize` as the number of bytes to be accessed, causing BasicAA
to return NoAlias:
a941e15074/llvm/lib/Analysis/BasicAliasAnalysis.cpp (L1658-L1667)
With `-aa-trace`, we get:
```
End ptr getelementptr inbounds nuw (i8, ptr @g, i64 4) @ LocationSize::precise(1), %gep1 = getelementptr i8, ptr %p, i64 4 @ LocationSize::precise(32) = NoAlias
```
This patch uses `getTypeStoreSize` to compute the correct access size
for LOps. Instead of modifying the MemoryLocation for End (i.e.,
`LOps.RootInsert`), it also uses the computed base and AATag for
correctness.
Closes https://github.com/llvm/llvm-project/issues/169921.
c7c6c0a45c