[AMDGPU] Do not consider indirect acces through phi for wave limiter

Rational: if there is indirect access that is usually an issue
because load is not ready by the use. However, if use is inside a
loop and load is outside that is potentially an issue for a first
iteration only.

Differential Revision: https://reviews.llvm.org/D47740

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334420 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed