This patch adds some unit tests for 32-bit subregister support. We want to make sure ALU32, subregister load/store and new peephole optimization are truely enabled once -mattr=+alu32 specified. Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Reviewed-by: Yonghong Song <yhs@fb.com> llvm-svn: 325992