[Bug target/79185] [5/6/7 Regression] register allocation in the addition of two 128 bit ints

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79185

--- Comment #5 from Jeffrey A. Law <law at redhat dot com> ---

Is the CLOBBER even necessary anymore?  Wasn't its only purpose to tell
dataflow that r88 was dead because our old flow analysis couldn't?

Doesn't the DF infrastructure get this right?  If it does, then we might be
able to drop the CLOBBER entirely which might simplify the problem.