[PATCH 3/3] Handle const_vector in mulv4si3 for pre-sse4.1.

Uros Bizjak ubizjak@gmail.com
Wed Jun 20 07:09:00 GMT 2012


On Mon, Jun 18, 2012 at 10:06 PM, Richard Henderson <rth@redhat.com> wrote:

>> Please note that you will probably hit PR33329, this is the reason
>> that we expand multiplications after reload. Please see [1] for
>> further explanation. There is gcc.target/i386/pr33329.c test to cover
>> this issue, but it is not effective anymore since the simplification
>> happens at tree level.
>>
>> [1] http://gcc.gnu.org/ml/gcc-patches/2007-09/msg00668.html
>
>
> Well, even with the test case changed s/*2/*12345/ so that the
> test case continues to use a multiply instead of devolving to
> a shift, does not fail.
>
> There have been a lot of changes since 2007; I might hope that
> the underlying bug has been fixed.

Should we also change mul<VI1_AVX2>3 and mul<VI8_AVX2>3 from
pre-reload splitter to an expander in the same way?

Uros.



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