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From: Richard Sandiford <richard.sandiford@arm.com>
To: Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>
Mail-Followup-To: Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>,gcc Patches <gcc-patches@gcc.gnu.org>, richard.sandiford@arm.com
Cc: gcc Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [SVE] [fwprop] PR88833 - Redundant moves for WHILELO-based loops
References: <CAAgBjMndm8upw++qigGPQNTA4nqm+Uck=CcVBpt3cZ74fEGEwA@mail.gmail.com>	<mptd0j3ib67.fsf@arm.com>	<CAAgBjM=z6g3R6Ai7nRcOShAXEp2dd44kFkmZUUf-=T+jfUFboQ@mail.gmail.com>
Date: Mon, 24 Jun 2019 14:21:00 -0000
In-Reply-To: <CAAgBjM=z6g3R6Ai7nRcOShAXEp2dd44kFkmZUUf-=T+jfUFboQ@mail.gmail.com>	(Prathamesh Kulkarni's message of "Mon, 24 Jun 2019 17:06:37 +0530")
Message-ID: <mptv9wvgj37.fsf@arm.com>
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Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org> writes:
> @@ -1415,6 +1460,19 @@ forward_propagate_into (df_ref use)
>    if (!def_set)
>      return false;
>  
> +  if (reg_prop_only
> +      && !REG_P (SET_SRC (def_set))
> +      && !REG_P (SET_DEST (def_set)))
> +    return false;

This should be:

  if (reg_prop_only
      && (!REG_P (SET_SRC (def_set)) || !REG_P (SET_DEST (def_set))))
    return false;

so that we return false if either operand isn't a register.

> +
> +  /* Allow propagations into a loop only for reg-to-reg copies, since
> +     replacing one register by another shouldn't increase the cost.  */
> +
> +  if (DF_REF_BB (def)->loop_father != DF_REF_BB (use)->loop_father
> +      && !REG_P (SET_SRC (def_set))
> +      && !REG_P (SET_DEST (def_set)))
> +    return false;

Same here.

OK with that change, thanks.

Richard