https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109592
--- Comment #2 from Feng Wang <wangfeng at eswincomputing dot com> ---
(In reply to Feng Wang from comment #1)
> Hi Jeff,
>
> I have modified some code according to your suggestion.
> In simplify-rtx.cc I add below part in canonicalize_shift:
> if ((code == ASHIFTRT)
> && is_a <scalar_int_mode> (mode, &int_mode)
> && GET_CODE (op0) == ASHIFT
> && CONST_INT_P (op1)
> && is_a <scalar_int_mode> (GET_MODE (op0), &inner_mode)
> && CONST_INT_P (XEXP (op0, 1))
> && (INTVAL (XEXP (op0, 1)) == INTVAL (op1)))
> {
> tem = XEXP (op0, 0);
> if (SUBREG_P(XEXP (op0, 0))
> && is_a <scalar_int_mode> (GET_MODE (SUBREG_REG (XEXP (op0,
> 0))),
> &inner_mode)
> && GET_MODE_BITSIZE (inner_mode) > GET_MODE_BITSIZE (int_mode))
> {
> tem = XEXP (XEXP (op0, 0), 0);
> }
>
> if ((INTVAL (op1) + 8 == 32) || (INTVAL (op1) + 8 == 64))
> {
> op0 = lowpart_subreg (E_QImode, tem, GET_MODE(tem));
> return simplify_gen_unary (SIGN_EXTEND, int_mode, op0, int_mode);
> }
>
> if ((INTVAL (op1) + 16 == 32) || (INTVAL (op1) + 16 == 64))
> {
> op0 = lowpart_subreg (E_HImode, tem, GET_MODE(tem));
> return simplify_gen_unary (SIGN_EXTEND, int_mode, op0, int_mode);
> }
> }
>
> and at the same time in fwprop.cc I add below conditions in classify_result
> to judge whether replacement is PROFITABLE
> /* If have load byte or load half pattern, we can covert
> ashiftrt(ashift(object)const)const to load byte or half form object */
> if (GET_CODE(old_rtx) == ASHIFTRT
> && GET_CODE(new_rtx) == SIGN_EXTEND
> && ((GET_MODE(new_rtx) == E_SImode
> && ((GET_MODE(XEXP(new_rtx, 0)) == E_QImode
> && HAVE_extendqisi2)
> || (GET_MODE(XEXP(new_rtx, 0)) == E_HImode
> && HAVE_extendhisi2)))
> ||(GET_MODE(new_rtx) == E_DImode
> && ((GET_MODE(XEXP(new_rtx, 0)) == E_QImode
> && HAVE_extendqidi2)
> || (GET_MODE(XEXP(new_rtx, 0)) == E_HImode
> && HAVE_extendhidi2))))
> return PROFITABLE;
>
> Please check if it is reasonable and look forward to further discussion with
> you.Thanks!
