From: Ira Rosen <ira.rosen@linaro.org>
To: Ulrich Weigand <uweigand@de.ibm.com>
Cc: gcc-patches@gcc.gnu.org, Patch Tracking <patches@linaro.org>
Subject: Re: [patch] Fix PR tree-optimization/49771
Date: Sun, 24 Jul 2011 14:32:00 -0000 [thread overview]
Message-ID: <CAKSNEw5zPPBn9+J9YO0fqmhYXmSVJr66AyT2kWipwR33BDyfZA@mail.gmail.com> (raw)
In-Reply-To: <CAKSNEw6E3fE9_z9hfV1NSHWn8Dvjg2ind8J0-dU33UW8gBxQ5A@mail.gmail.com>
On 21 July 2011 15:19, Ira Rosen <ira.rosen@linaro.org> wrote:
> On 20 July 2011 21:35, Ulrich Weigand <uweigand@de.ibm.com> wrote:
>>
>> The return value of foo with vectorization is 1249 instead
>> of 1999 for some reason.
>
> I reproduced the failure. It occurs without Richard's
> (http://gcc.gnu.org/ml/gcc-patches/2011-07/msg01022.html) and this
> patches too. Obviously the vectorized loop is executed, but at the
> moment I don't understand why. I'll have a better look on Sunday.
Actually it doesn't choose the vectorized code. But the scalar version
gets optimized in a harmful way for SPU, AFAIU.
Here is the scalar loop after vrp2
<bb 8>:
# ivtmp.42_50 = PHI <ivtmp.42_59(3), ivtmp.42_45(10)>
D.4593_42 = (void *) ivtmp.53_32;
D.4520_33 = MEM[base: D.4593_42, offset: 0B];
D.4521_34 = D.4520_33 + 1;
MEM[symbol: a, index: ivtmp.42_50, offset: 0B] = D.4521_34;
ivtmp.42_45 = ivtmp.42_50 + 4;
if (ivtmp.42_45 != 16)
goto <bb 10>;
else
goto <bb 5>;
and the load is changed by dom2 to:
<bb 4>:
...
D.4520_33 = MEM[base: vect_pa.9_19, offset: 0B];
...
where vector(4) int * vect_pa.9;
And the scalar loop has no rotate for that load:
.L3:
lqd $13,0($2)
lqx $11,$5,$3
cwx $7,$sp,$3
ai $12,$13,1
shufb $6,$12,$11,$7
stqx $6,$5,$3
ai $3,$3,4
ceqi $4,$3,16
I manually added rotqby for $13 and the result was correct (I changed
the test to iterate only 4 times to make the things easier).
Ira
>
> Ira
>
>>
>> Bye,
>> Ulrich
>>
>> --
>> Dr. Ulrich Weigand
>> GNU Toolchain for Linux on System z and Cell BE
>> Ulrich.Weigand@de.ibm.com
>>
>
next prev parent reply other threads:[~2011-07-24 12:02 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-19 8:24 Ira Rosen
2011-07-19 9:49 ` Richard Guenther
2011-07-19 14:01 ` Ira Rosen
2011-07-19 14:03 ` Richard Guenther
2011-07-20 19:47 ` Ulrich Weigand
2011-07-21 12:54 ` Ira Rosen
2011-07-24 14:32 ` Ira Rosen [this message]
2011-07-24 18:46 ` Richard Guenther
2011-07-25 9:44 ` Ulrich Weigand
2011-07-25 10:08 ` Richard Guenther
2011-07-25 11:26 ` Ira Rosen
2011-07-25 11:41 ` Richard Guenther
2011-07-25 12:33 ` Ira Rosen
2011-07-25 13:01 ` Richard Guenther
2011-07-25 13:07 ` Richard Guenther
2011-07-25 13:47 ` Ulrich Weigand
2011-07-25 14:01 ` Richard Guenther
2011-07-25 14:10 ` Richard Guenther
2011-07-25 14:14 ` Richard Guenther
2011-07-25 14:54 ` Ulrich Weigand
2011-07-25 14:59 ` Richard Guenther
2011-07-25 16:12 ` Ulrich Weigand
2011-07-26 8:25 ` Richard Guenther
2011-07-26 8:59 ` Andrew Pinski
2011-07-26 14:23 ` Ulrich Weigand
2011-07-26 14:25 ` Michael Matz
2011-07-26 16:18 ` Merge alignments from coalesced SSA pointers Michael Matz
2011-07-26 17:23 ` Michael Matz
2011-08-08 16:34 ` Ulrich Weigand
2011-08-09 12:01 ` Michael Matz
2011-08-12 16:41 ` [rfa] Set alignment of pseudos via get_pointer_alignment Michael Matz
2011-08-12 22:53 ` Richard Guenther
2011-08-23 15:04 ` Michael Matz
2011-07-26 17:28 ` Merge alignments from coalesced SSA pointers Ulrich Weigand
2011-07-27 9:13 ` Richard Guenther
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