Handle CONSTRUCTOR in operand_equal_p

[Jeff Law]

On 10/14/2015 10:27 AM, Jan Hubicka wrote:
> Hi,
> this patch adds the CONSTRUCTOR case discussed while back.  Only empty
> constructors are matched, as those are only appearing in gimple operand.
> I tested that during bootstrap about 7500 matches are for empty ctors.
> There are couple hundred for non-empty probably used on generic.
>
> Bootstrapped/regtested x86_64-linux, OK?
>
> Honza
>
> 	* fold-const.c (operand_equal_p): Match empty constructors.
OK.  It'd be useful to have a test which shows that matching these 
results in some kind of difference we can see in the dump files.

jeff