Re: [Patch] Fix bug for frame instructions in annulled delay slots

[Jeff Law <law@redhat.com>]

On 12/07/2015 02:18 PM, Steve Ellcey wrote:
> On Mon, 2015-12-07 at 12:30 -0700, Jeff Law wrote:
>> On 12/07/2015 12:28 PM, Bernd Schmidt wrote:
>>> On 12/07/2015 07:54 PM, Steve Ellcey  wrote:
>>>>          if (must_annul)
>>>> -        used_annul = 1;
>>>> +        {
>>>> +          /* Frame related instructions cannot go into annulled delay
>>>> +         slots, it messes up the dwarf info.  */
>>>> +          if (RTX_FRAME_RELATED_P (trial))
>>>> +        return;
>>>
>>> Don't you need to use break rather than return?
>>>
>>>> +      else if (!RTX_FRAME_RELATED_P (trial) \
>>>
>>> Stray backslash
>>> Other than that I think this is OK. There are some preexisting tests for
>>> frame related insns already in this code.
>> Also note there's probably port cleanup that could happen once this goes
>> in.  IIRC the PA port (for example) explicitly disallows frame related
>> insns from many (most, all?) delay slots.  Other targets may be doing
>> something similar.
>>
>> jeff
>
> If I had remembered/seen that code in pa.md earlier I might have fixed
> MIPS the same way.  Oh well, I guess changing reorg.c is the better way
> to do it since it can be shared now.
Agreed.

> executed when the branch is taken (vs. untaken).  I think
> steal_delay_list_from_fallthrough is only going to be used when the
> delay slot is executed on a branch-not-taken.  Are there any machines
> like that?
?  I don't think it's restricted to cases where the delay slot is 
executed only on a branch-not-taken.

Jeff