https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59291
--- Comment #4 from Oleg Endo <olegendo at gcc dot gnu.org> ---
(In reply to pietro from comment #3)
> The following peehole:
>
> (define_peephole
> [(set (match_operand:SI 0 "arith_reg_dest")
> (plus:SI (match_dup 0)
> (match_operand:SI 1 "arith_reg_operand")))
> (set (match_operand:SI 2 "arith_reg_dest")
> (plus:SI (match_dup 2)
> (const_int 1)))]
> "TARGET_SH1
> && REGNO (operands[0]) == REGNO (operands[2])"
> {
> return "sett" "\n"
> "\taddc %1,%0";
> })
>
The use of old style text based peepholes is not preferred in general. Other
than that, reducing the live ranges of the T bit register (by grouping the
related insns closer together) should be better done much earlier, before
register allocation. (peephole pass is done way later in the optimization
flow).
