[CodeGen] Don't attempt a tail-call with implicit sret.

Tailcalls are only OK with forwarded sret pointers. With sret demotion,
they're not, as we'd have a pointer into a soon-to-be-dead stack frame.

Differential Revison: http://reviews.llvm.org/D8510


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233409 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed