[PATCH] Fix PR69291, RTL if-conversion bug

[Bernd Schmidt]

On 02/10/2016 02:50 PM, Richard Biener wrote:
> On Wed, 10 Feb 2016, Bernd Schmidt wrote:
>
>> On 02/10/2016 02:35 PM, Richard Biener wrote:
>>
>>> Index: gcc/ifcvt.c
>>> ===================================================================
>>> --- gcc/ifcvt.c (revision 233262)
>>> +++ gcc/ifcvt.c (working copy)
>>> @@ -1274,7 +1274,8 @@ noce_try_store_flag_constants (struct no
>>>          && CONST_INT_P (XEXP (a, 1))
>>>          && CONST_INT_P (XEXP (b, 1))
>>>          && rtx_equal_p (XEXP (a, 0), XEXP (b, 0))
>>> -      && noce_operand_ok (XEXP (a, 0))
>>> +      && (REG_P (XEXP (a, 0))
>>> +         || ! reg_mentioned_p (if_info->x, XEXP (a, 0)))
>>
>> I guess that would also work. Could maybe use a brief comment.
>
> Ok.  I'm testing that.  I wonder if we need to use reg_overlap_mentioned_p
> here (hard-reg pairs?) or if reg_mentioned_p is safe.

Let's go with reg_overlap_mentioned_p. I kind of forgot about that once 
I thought of possible issues with emitting a move :-(


Bernd