physical register that is described in a DBG_VALUE.
In the testcase the DBG_VALUE describing "p5" becomes unavailable
because the register its address is in is clobbered and we (currently)
aren't smart enough to realize that the value is rematerialized immediately
after the DBG_VALUE and/or is actually a stack slot.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227056 91177308-0d34-0410-b5e6-96231b3b80d8