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From: Eric Botcazou <ebotcazou@libertysurf.fr>
To: Richard Henderson <rth@redhat.com>
Subject: Re: [cft] subreg validation round 2
Date: Fri, 19 Nov 2004 22:43:00 -0000
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References: <20041117184009.GA12257@redhat.com> <200411172021.21297.ebotcazou@libertysurf.fr> <20041119210240.GA18341@redhat.com>
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> > How did you address the problem with SPARC splitters?
>
> @@ -3674,14 +3676,15 @@ simplify_subreg (enum machine_mode outer
>        && subreg_offset_representable_p (REGNO (op), innermode,
>  					byte, outermode))
>      {
> -      rtx tem = gen_rtx_SUBREG (outermode, op, byte);
> -      int final_regno = subreg_hard_regno (tem, 0);
> +      unsigned int regno = REGNO (op);
> +      unsigned int final_regno
> +	= regno + subreg_regno_offset (regno, innermode, byte, outermode);

Ouch!  Pretty deeply buried in the subreg handling stuff.

Would you see any advantage in manually building the hard regs within the 
splitters?

-- 
Eric Botcazou