Codegen (Reg|imm)+&GV as an LEA, because we cannot put it into the immediate field

of an ADDri (due to current restrictions on MachineOperand :( ).  This allows
us to generate:

        leal Data+16000, %edx

instead of:

        movl $Data, %edx
        addl $16000, %edx

llvm-svn: 19420