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Re: [PATCH,rs6000] fix ICE caused by lax rs6000_legitimize_address

On Tue, Nov 11, 2008 at 07:19:11AM -0800, Nathan Froyd wrote:
> --- gcc/config/rs6000/rs6000.c	(revision 141763)
> +++ gcc/config/rs6000/rs6000.c	(working copy)
> @@ -3813,6 +3813,12 @@ rs6000_legitimize_address (rtx x, rtx ol
>        HOST_WIDE_INT high_int, low_int;
>        rtx sum;
>        low_int = ((INTVAL (XEXP (x, 1)) & 0xffff) ^ 0x8000) - 0x8000;
> +      /* Using a REG+CONST 64-bit integer load on 64-bit platforms
> +	 requires that CONST be word-aligned.  */
> +      if (TARGET_POWERPC64
> +	  && (mode == DImode || mode == DDmode)
> +	  && (low_int & 0x3))
> +	low_int &= (HOST_WIDE_INT) ~3;
>        high_int = INTVAL (XEXP (x, 1)) - low_int;
>        sum = force_operand (gen_rtx_PLUS (Pmode, XEXP (x, 0),
>  					 GEN_INT (high_int)), 0);

Is this really worth doing?  How does the generated code compare with
simply returning NULL from rs6000_legitimize_address for this case?

-- 
Alan Modra
Australia Development Lab, IBM
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