Argument promotion can replace an argument of a call with an alloca. This
requires clearing the tail marker as it is very likely that the callee is now
using an alloca in the caller.
This fixes pr14710.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199909 91177308-0d34-0410-b5e6-96231b3b80d8