emit-rtl.c (offset_address): Use simplify_gen_binary rather than gen_rtx_PLUS to form the sum.

        * emit-rtl.c (offset_address): Use simplify_gen_binary rather
        than gen_rtx_PLUS to form the sum.
        * explow.c (force_reg): Rearrange to not allocate new pseudo
        when force_operand returns a register.
        * expr.c (expand_assignment): Allow offset_rtx expansion to
        return a sum.  Do not force addresses into registers.
        (expand_expr): Likewise.
        * simplify-rtx.c (simplify_gen_binary): Use simplify_plus_minus
        to canonicalize arithmetic that didn't simpify.
        (simplify_plus_minus): New argument force; update
        all callers.  Don't split CONST unless we can do something with it,
        and wouldn't lose the constness of the operands.

        * config/i386/i386.c (legitimize_pic_address): Recognize UNSPECs
        that we generated earlier.

From-SVN: r49945