This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH, i386, Pointer Bounds Checker 33/x] MPX ABI


On Fri, Oct 10, 2014 at 7:29 PM, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
> 2014-10-10 21:10 GMT+04:00 Uros Bizjak <ubizjak@gmail.com>:
>> On Wed, Oct 1, 2014 at 8:57 PM, Vladimir Makarov <vmakarov@redhat.com> wrote:
>>
>>> The problem is in code introduced by Bernd in IRA and caller-saves.c in
>>> 2012.  It is basically an optimization for functions returning always the
>>> same result as one argument (e.g. memcpy returning 1st argument).
>>>
>>> There are two possible solutions.  First one is to prohibit the
>>> optimizations when there is a parallel in SET.  Second one is to go deeper
>>> if the call result is guaranteed in the first element which is true for the
>>> patch.
>>
>> I suspect that the first solution will regress
>> gcc.target/i386/retarg.c on i686 - that testcase test if referred
>> optimization is effective. All things equal, I think we should go with
>> the second solution.
>
> The first solutions is in trunk since October 3
> (https://gcc.gnu.org/ml/gcc-cvs/2014-10/msg00094.html) and I don't see
> such fail.  Patch actually just checks for a case which never occurs
> right now and therefore should be quite safe.

True, but after MPX patches are committed, PARALLELs will be passed as
call targets. I wonder if the testcase fails then.

Uros.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]