[clang] [clang][CodeGen] Add TBAA for bit-field accesses (PR #226806)

[Dávid Bolvanský via cfe-commits]

davidbolvansky wrote:

No, this did not start from the FIXME. I was comparing GCC and Clang on code with bit-fields and noticed that GCC could eliminate reloads that Clang kept. After looking into it, the difference came down to alias analysis: Clang was missing TBAA information for these accesses. That was the motivation for this PR — to close that optimization gap with GCC.


https://github.com/llvm/llvm-project/pull/226806