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Re: [PATCH] Fix PR70011 (backlevel test case)
- From: David Edelsohn <dje dot gcc at gmail dot com>
- To: Bill Schmidt <wschmidt at linux dot vnet dot ibm dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 29 Feb 2016 21:20:42 -0500
- Subject: Re: [PATCH] Fix PR70011 (backlevel test case)
- Authentication-results: sourceware.org; auth=none
- References: <1456764577 dot 8013 dot 8 dot camel at oc8801110288 dot ibm dot com>
On Mon, Feb 29, 2016 at 11:49 AM, Bill Schmidt
<wschmidt@linux.vnet.ibm.com> wrote:
> Hi,
>
> PR70011 identifies an old vectorization test that recently started
> failing on GCC 6 with POWER8 hardware. This "failure" is that we now
> find vectorization of the test case to be profitable, where it didn't
> used to be. A combination of two factors allowed this to become
> profitable here: First, the POWER8 feature that unaligned vector
> accesses are supported by hardware; and second, some improvement in the
> vectorizer itself (vect_recog_mult_pattern now kicks in).
>
> The proposed fix herein is to XFAIL the test for vectorization failure
> for POWER subtargets that support efficient unaligned vector accesses.
> Since this also requires the vectorization improvement that only occurs
> in GCC 6, it makes sense to only make this change on trunk.
>
> I've verified the modified test on powerpc64le-unknown-linux-gnu
> (POWER8) and on powerpc64-unknown-linux-gnu (both POWER7 and POWER8) and
> everything works as expected. Is this ok for trunk?
>
> Thanks,
> Bill
>
>
> 2016-02-29 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
>
> PR target/70011
> * gcc.dg/vect/costmodel/ppc/costmodel-fast-math-vect-pr299925.c:
> XFAIL when hardware supports efficient unaligned storage access.
Okay.
Thanks, David