[PR target/85401] initialize the move cost table before using it (in another place, too)

[Jeff Law]

On 10/4/19 7:23 AM, coypu@sdf.org wrote:
> On Tue, Oct 01, 2019 at 01:26:16PM -0600, Jeff Law wrote:
>> On 9/30/19 2:45 PM, coypu@sdf.org wrote:
>>> On Mon, Sep 30, 2019 at 11:46:24AM -0400, Vladimir Makarov wrote:
>>>> Yes, the patch is mostly ok.  You can commit it into the trunk after
>>>> applying changes mentioned below. If you do not have a write access, let me
>>>> know I'll commit the patch by myself.
>>> I don't have commit access. It would be nice if you committed it :)
>> I took care of the nits and committed the patch.
>>
>>
>>>> It would be nice to add a small test too.  But it is not obligatory for this
>>>> case as the patch is obvious and it might be hard to create a small test to
>>>> reproduce the bug.
>>> I have the C code that produces this failure. I can creduce it, but I'm
>>> not sure there's a relationship between it and the bug.
>>> Doing unrelated changes (adding instruction scheduling) to vax also hid it.
>>>
>>> Is this kind of test still valuable?
>> Often they are.
>>
>> jeff
> So it was. Here's another missed initialization, that running creduce
> accidentally reached.
> 
> 
> 
> The mode might have changed, let's make sure the new mode is initialized
> too.
> 
> 2019-10-04	Maya Rashish <coypu@sdf.org>
> 	* ira-color.c (update_costs_from_allocno): Call
> 	ira_init_register_move_cost_if_necessary.
THanks.  Installed
jeff

ps. You might want to read this from John Regehr.  It touches on how
reducers tend to also find independent bugs.

https://blog.regehr.org/archives/1284