Re: [PATCH] Fix PR80281

[Christophe Lyon <christophe.lyon@linaro.org>]

On 5 April 2017 at 13:41, Bin.Cheng <amker.cheng@gmail.com> wrote:
> On Wed, Apr 5, 2017 at 12:38 PM, Markus Trippelsdorf
> <markus@trippelsdorf.de> wrote:
>> On 2017.04.03 at 15:20 +0200, Richard Biener wrote:
>>> I'm re-testing the following variant.
>>>
>>> Richard.
>>>
>>> 2017-04-03  Richard Biener  <rguenther@suse.de>
>>>
>>>       PR middle-end/80281
>>>       * match.pd (A + (-B) -> A - B): Make sure to preserve unsigned
>>>       arithmetic done for the negate or the plus.  Simplify.
>>>       (A - (-B) -> A + B): Likewise.
>>>       * fold-const.c (split_tree): Make sure to not negate pointers.
>>>
>>>       * gcc.dg/torture/pr80281.c: New testcase.
>>
>> gcc.dg/tree-ssa/pr40921.c started to fail with -march=skylake:
>>
>>  % gcc -march=skylake -c -O2 -fdump-tree-optimized -ffast-math -c gcc.dg/tree-ssa/pr40921.c
>>  % cat pr40921.i.227t.optimized | grep "\-y"
>>    _3 = -y_4(D);
> Also on AArch64.
>

And on some arm configurations, if that's easier to reproduce:
* -mthumb/-march=armv8-a/-mfpu=crypto-neon-fp-armv8/-mfloat-abi=hard
* --with-cpu=cortex-a15 --with-fpu=neon-vfpv4
* --with-cpu=cortex-a57 --with-fpu=crypto-neon-fp-armv8

Thanks,

Christophe

> Thanks,
> bin
>>
>> --
>> Markus