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Re: powerpc compare_and_swap fails
On Thu, Nov 17, 2011 at 3:25 PM, Richard Henderson <rth@redhat.com> wrote:
> On 11/17/2011 12:37 AM, Alan Modra wrote:
>> - ? ? ?oldval = convert_modes (SImode, mode, oldval, 1);
>> + ? ? ?oldval = gen_reg_rtx (SImode);
>> + ? ? ?convert_move (oldval, orig, 1);
>> ? ? ? ?oldval = expand_simple_binop (SImode, ASHIFT, oldval, shift,
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? oldval, 1, OPTAB_LIB_WIDEN);
>
> Gah. ?From convert_modes, oldval is a subreg, and modifying that
> subreg gets us into all sorts of trouble. ?The fix should be as
> simple as
>
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? oldval, 1, OPTAB_LIB_WIDEN);
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? NULL_RTX, 1, OPTAB_LIB_WIDEN);
>
> so that we don't write back into the subreg.
Richard,
Are you going to test and apply the fix or do you want Alan and I to do it?
Thanks, David