This change is the first part of the AMDGPU target description change. The aim of it is the effective splitting the vector and scalar flows at the selection stage. Selection uses predicate functions based on the framework implemented earlier: https://reviews.llvm.org/D35267
Tests: CodeGen/AMDGPU on Win32
make check-llvm on lnx
You can create enum for the mode in SIInstrInfo.td. Look at SIEncodingFamily as an example.
Then I might be missing something, but I do not see anywhere a value 1 used for mode.