[PATCH 4/4] Un-XFAIL ssa-dom-cse-2.c for most platforms

[Alan Lawrence]

It seems the conclusion on PowerPC is to XFAIL the test on powerpc64 (there will 
be XPASSes with -mcpu=power7 or -mcpu=power8). Which is what the original patch 
does (https://gcc.gnu.org/ml/gcc-patches/2015-12/msg01979.html). So,

Ping.

Thanks, Alan

On 21/12/15 15:33, Bill Schmidt wrote:
> On Mon, 2015-12-21 at 15:22 +0000, Alan Lawrence wrote:
>> On 21/12/15 14:59, Bill Schmidt wrote:
>>>>>
>>>>> On powerpc64, the test passes with -mcpu=power8 (the loop is vectorized as a
>>>>> reduction); however, without that, similar code is generated to Alpha (the
>>>>> vectorizer decides the reduction is not worthwhile without SIMD support), and
>>>>> the test fails; hence, I've XFAILed for powerpc, but I think I could condition
>>>>> the XFAIL on powerpc64 && !check_p8vector_hw_available, if preferred?
>>>>
>>>> Fun.
>>>>
>>>> Does it work with -mcpu=power7?
>>
>> Yes, it works with -mcpu=power7, as well as -mcpu=power8, but not e.g. -mcpu=power6.
>>
>>>> Bill: What GCC DejaGNU incantation would you like to see?
>>>
>>> This sounds like more fallout from unaligned accesses being faster on
>>> POWER8 than previous hardware.  What about conditioning the XFAIL on
>>>
>>> { powerpc*-*-* && { ! vect_hw_misalign } }
>>>
>>> -- does this work properly?
>>
>> Not on a stage1 compiler - check_p8vector_hw_available itself requires being
>> able to run executables - I'll check on gcc112. However, both look like they're
>> really about the host (ability to execute an asm instruction), not the target
>> (/ability for gcc to output such an instruction)....
>
> Hm, that looks like a pervasive problem for powerpc.  There are a number
> of things that are supposed to be testing effective target but rely on
> check_p8vector_hw_available, which as you note requires executing an
> instruction and is really about the host.  We need to clean that up; I
> should probably open a bug.  Kind of amazed this has gotten past us for
> a couple of years.
>
> For now, just XFAILing for powerpc seems the best alternative for this
> test.
>
> Thanks,
> Bill
>
>>
>> --Alan
>>
>
>