On Wed, Nov 28, 2012 at 12:58 AM, Steven Bosscher <stevenb....@gmail.com> wrote:
> On Wed, Nov 28, 2012 at 12:53 AM, Steven Bosscher wrote:
>> On Wed, Nov 28, 2012 at 12:47 AM, Eric Botcazou wrote:
>>>> Count me in, too. So let's avoid it:
>>>>
>>>> * gcse.c (struct reg_use): Remove unused struct.
>>>> (gcse_emit_move_after): Do not create REG_EQUAL notes that
>>>> reference
>>>> the SET_DEST of the instruction the note would be attached to.
>>>
>>> OK (with PR rtl-optimization/55006) if it passes bootstrap & regtest,
>>> thanks.
>>
>> Thanks for the quick review.
>>
>>
>>>> And perhaps a bit in emit-rtl.c for good measure? I'll see if/where
>>>> this causes breakage...
>>>
>>> I think this would need to be wrapped in a #ifdef ENABLE_CHECKING/#endif
>>> pair.
>>
>> Well, let me first try to make it pass some set of tests. This breaks
>> the compiler in too many places to name right now. Here's the first of
>> what's probably going to be a whole series of patches if I keep
>> hitting this internal_error as often as I am now in my set of cc1-i
>> files...
>>
>> I know: ChangeLog, testing and all that. That's not the point yet.
>> This is just a brain dump, to get this saved in some places safer than
>> the compile farm or (worse) my head ;-)
>
> And another one:
And one to end the night here.
Again: Is this really the direction we should be going in? (I haven't
any better ideas...)
Index: fwprop.c
===================================================================
--- fwprop.c (revision 193394)
+++ fwprop.c (working copy)
@@ -1321,7 +1321,9 @@ forward_propagate_and_simplify (df_ref u
separately try plugging the definition in the note and simplifying.
And only install a REQ_EQUAL note when the destination is a REG,
as the note would be invalid otherwise. */
- set_reg_equal = (note == NULL_RTX && REG_P (SET_DEST (use_set)));
+ set_reg_equal = (note == NULL_RTX && REG_P (SET_DEST (use_set))
+ && ! reg_mentioned_p (SET_DEST (use_set),
+ SET_SRC (use_set)));
}
if (GET_MODE (*loc) == VOIDmode)
