AMDGPU: Fix handling of constant phi input loop conditions

If the loop condition was an i1 phi with a constantexpr input, this
would add a loop intrinsic fed by a phi dependent on a call to
if.break in the same block. Insert the call in the loop header.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298121 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed