PATCH [5/n]: Prepare x32: PR middle-end/48016: Inconsistency in non-local goto save area

Richard Guenther richard.guenther@gmail.com
Thu Jun 16 08:02:00 GMT 2011


On Wed, Jun 15, 2011 at 9:55 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Wed, Jun 15, 2011 at 8:16 AM, Michael Matz <matz@suse.de> wrote:
>> Hi,
>>
>> On Wed, 15 Jun 2011, H.J. Lu wrote:
>>
>>> >> +  /* FIXME: update_nonlocal_goto_save_area may pass SA in the wrong mode.  */
>>> >> +  if (GET_MODE (sa) != mode)
>>> >> +    {
>>> >> +      gcc_assert (ptr_mode != Pmode
>>> >> +               && GET_MODE (sa) == ptr_mode
>>> >> +               && mode == Pmode);
>>> >> +      sa = adjust_address (sa, mode, 0);
>>> >> +    }
>>> >
>>> > That may be appropriate for a branch, but trunk shouldn't contain FIXMEs
>>> > that explain how something should be fixed, instead that something should
>>> > be carried out.  I.e. just fix update_nonlocal_goto_save_area.
>>> >
>>>
>>> I don't know update_nonlocal_goto_save_area enough to fix it
>>> without breaking other targets.  This patch is the lest invasive.
>>> Any suggestions how to properly fix it is appreciated.
>>
>> Well, the most obvious variant would be to move the above code right
>> before the call of emit_stack_save in update_nonlocal_goto_save_area
>> (using r_save and STACK_SAVEAREA_MODE (SAVE_NONLOCAL)).  All other callers
>> of emit_stack_save already make sure to pass an object of correct mode, so
>> this one should too.
>>
>> But I think it's better to just produce a correct array_ref from the
>> start.  get_nl_goto_field creates an array_type for the
>> nonlocal_goto_save_area of correct type (ptr_type_node or
>> lang_hooks.types.type_for_mode (Pmode, 1)), and we should use that.
>>
>> So something like this in update_nonlocal_goto_save_area:
>>  t_save = build4 (ARRAY_REF,
>>                   TREE_TYPE (TREE_TYPE (cfun->nonlocal_goto_save_area)),
>>                   cfun->nonlocal_goto_save_area,
>>                   integer_one_node, NULL_TREE, NULL_TREE);
>>
>> instead of the current building of t_save.  Then r_save also should get
>> the correct mode automatically.
>>
>
> Here is the updated patch.  OK for trunk?

The explow.c change is ok.  For the function.c change I wonder why
convert_memory_address doesn't do the right thing - from it's documentation
it definitely should, so it should be fixed instead of being replaced by
adjust_address with a zero offset.

Richard.

> Thanks.
>
> --
> H.J.
> ---
> 2011-06-15  H.J. Lu  <hongjiu.lu@intel.com>
>
>        PR middle-end/48016
>        * explow.c (update_nonlocal_goto_save_area): Use proper mode
>        for stack save area.
>
>        * function.c (expand_function_start): Properly store frame
>        pointer for non-local goto.
>



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