Re: [4.6] Fix type of SRAed enum accesses

[Richard Guenther <richard.guenther@gmail.com>]

On Tue, Oct 18, 2011 at 2:21 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Tue, Sep 27, 2011 at 03:26:03PM +0100, Richard Sandiford wrote:
>> This patch fixes a miscompilation of stage1 c-parser.o in an ARM bootstrap.
>> When an access to an enum field was SRAed, a component ref used the type
>> of the integer temporary variable instead of the type of the enum.
>> It therefore didn't alias other accesses to the same structure,
>> and was scheduled after a copy-load.
>>
>> Tested on x86_64-linux-gnu, and by verifying that c-parser.o is correctly
>> compiled for ARM after the patch.  Martin says he's going to test on ia64
>> too (thanks) -- I'll add 50326 to the changelog if that goes OK.
>>
>> OK to install if there are no regressions on ia64?
>
> As mentioned in bugzilla, the patch that caused this regression has been
> committed to 4.6 branch as well.
>
> Here is a backport of that patch to 4.6 branch, bootstrapped/regtested on
> x86_64-linux and i686-linux and Matthias AFAIK bootstrapped it on ia64-linux
> (where it previously failed to bootstrap because of this), regtest pending.
>
> Ok for 4.6?

Ok.

Richard.

> 2011-10-18  Jakub Jelinek  <jakub@redhat.com>
>
>        PR target/50350
>        Backport from mainline
>        2011-09-27  Richard Sandiford  <rdsandiford@googlemail.com>
>
>        PR middle-end/50386
>        PR middle-end/50326
>        * tree-sra.c (build_ref_for_model): Use the type of the field as
>        the type of the COMPONENT_REF.
>
> --- gcc/tree-sra.c.jj   2011-09-30 17:19:10.000000000 +0200
> +++ gcc/tree-sra.c      2011-10-18 08:01:28.682647833 +0200
> @@ -1448,12 +1448,12 @@ build_ref_for_model (location_t loc, tre
>  {
>   if (TREE_CODE (model->expr) == COMPONENT_REF)
>     {
> -      tree t, exp_type;
> -      offset -= int_bit_position (TREE_OPERAND (model->expr, 1));
> +      tree t, exp_type, fld = TREE_OPERAND (model->expr, 1);
> +      offset -= int_bit_position (fld);
>       exp_type = TREE_TYPE (TREE_OPERAND (model->expr, 0));
>       t = build_ref_for_offset (loc, base, offset, exp_type, gsi, insert_after);
> -      return fold_build3_loc (loc, COMPONENT_REF, model->type, t,
> -                             TREE_OPERAND (model->expr, 1), NULL_TREE);
> +      return fold_build3_loc (loc, COMPONENT_REF, TREE_TYPE (fld), t, fld,
> +                             NULL_TREE);
>     }
>   else
>     return build_ref_for_offset (loc, base, offset, model->type,
>
>        Jakub
>