R600/SI: Custom lower i1 stores

These are sometimes created by the shrink to boolean optimization in the
globalopt pass.

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203280 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Using SGPRs is illegal for instructions that read carry-out from VCC

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203281 91177308-0d34-0410-b5e6-96231b3b80d8