Re: [PR58315] reset inlined debug vars at return-to point

[Jeff Law <law@redhat.com>]

On 03/09/15 08:38, Richard Biener wrote:
> On Fri, Mar 6, 2015 at 7:04 PM, Alexandre Oliva <aoliva@redhat.com> wrote:
>> On Feb 26, 2015, Alexandre Oliva <aoliva@redhat.com> wrote:
>>
>>> So far, all the differences I looked at were caused by padding at the
>>> end of BBs, and by jump stmts without line numbers at the end of BBs,
>>> both right after the debug reset stmts the proposed patch introduces.
>>
>> Further investigation showed there were other sources of spurious
>> differences:
>>
>> - copies arising from the expansion of PHI nodes; source code
>>    information associated with these copies points at the source of the
>>    copy, which is hardly useful and sensible.
>
> Care to explain?  We spend quite some resources to maintain them
> (locations on PHI args, that is).
I almost responded to that claim as well, but then thought better of it 
as that patch (AFAICT) wasn't proposed for inclusion, but was being used 
for testing purposes.

Expansion of the PHI into copies should have locations which point to 
the source of the various PHI args.  Those are quite meaningful.

Jeff