When converting a malloc stored to a global into a global, we will
introduce an i1 flag to track whether the global has been initialized.
In case of atomic loads/stores, this will result in verifier failures,
because atomic ops on i1 are illegal. Even if we changed this to i8, I
don't think it is a good idea to change atomic types in that way.
Instead, bail out of the transform is we encounter any atomic
loads/stores of the global.
Fixes https://github.com/llvm/llvm-project/issues/137152.
(cherry picked from commit 57530c23a53b5e003d389437637f61c5b9814e22)
1cf8c7797d