https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70164
--- Comment #12 from Jeffrey A. Law <law at redhat dot com> --- Slight correction. I was looking at the wrong part of the dump when I said cse1 didn't change insn 28. It is cse1 that changes insn 28. So this is strictly an issue with the transformations cse1 makes.
