https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #19 from Jeffrey A. Law ---
I stumbled over this as well as some point. One thing I started playing with,
but had to set aside was making vect_get_range_info smarter.
In particular the case I was looking at VAR would have a single
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #18 from Kewen Lin ---
Created attachment 46687
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46687&action=edit
Powerpc case on vector rotation
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #17 from Segher Boessenkool ---
Yup, those testcases work fine for powerpc, too; and the signed versions of
those
do as well. (I couldn't find vector-types.h; I did "#define VECTOR_SIZE 16").
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #16 from Jorn Wolfgang Rennecke ---
Going from gcc 8.2 to gcc 9.1, I find the following two test cases are now
autovectorized:
/* { dg-do compile } */
/* { dg-options "-O3" } */
/* Test auto-vectorization */
#include "vector-types.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #15 from Richard Biener ---
The pattern recognizer could apply some of these tricks. I'd rather not have
GIMPLE narrow the operations and putting in MIN/MAX ops to make the code not
undefined...
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #14 from Jorn Wolfgang Rennecke ---
(In reply to Jorn Wolfgang Rennecke from comment #12)
> If we are right shifting a signed type, we could apply a MAX operation to the
> shift count.
Oops, I mean MIN of course. So that we can guar
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #13 from Jorn Wolfgang Rennecke ---
If the shifted value is 16 bit and int is 32 bit wide, then, depending
on target costs, instead of a vector compare, we might decide to use
a sign extract of bit 4 of the shift count instead.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #12 from Jorn Wolfgang Rennecke ---
If we are left shifting a narrow signed type for the result, and no defined
overflow semantics are in place, it should be OK to just vectorize the code
using the result type.
If we are right shifti
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
Jorn Wolfgang Rennecke changed:
What|Removed |Added
CC||amylaar at gcc dot gnu.org
---
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
Segher Boessenkool changed:
What|Removed |Added
CC||segher at gcc dot gnu.org
--- Comme
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
Marc Glisse changed:
What|Removed |Added
CC||law at gcc dot gnu.org
--- Comment #9 from
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #8 from alalaw01 at gcc dot gnu.org ---
Is there a case where the result is different with vs without all the
extending/truncating?
It seems we should need the extending/truncating on vectors exactly iff we need
it on scalars?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
--- Comment #7 from Andrew Pinski ---
(In reply to alalaw01 from comment #6)
> Same problem on AArch64 (at -O3). We've decided the shift is to be done on
> integers, widening the arguments and then truncating, before we hit the
> vectorizer:
Thi
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
alalaw01 at gcc dot gnu.org changed:
What|Removed |Added
CC||alalaw01 at gcc dot gnu.org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40073
Marc Glisse changed:
What|Removed |Added
Status|UNCONFIRMED |NEW
Last reconfirmed|
--
rguenth at gcc dot gnu dot org changed:
What|Removed |Added
CC||rguenth at gcc dot gnu dot
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--- Comment #1 from meissner at linux dot vnet dot ibm dot com 2009-05-08
16:59 ---
Created an attachment (id=17827)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17827&action=view)
test case
This code is an example of the code that generates sub-optimal code.
--
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--- Comment #5 from meissner at linux dot vnet dot ibm dot com 2009-05-08
17:06 ---
Created an attachment (id=17831)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17831&action=view)
Vectorizer verbose output
This is the output from the Powerpc compiler with -fdump-tree-vect
-ftre
--- Comment #4 from meissner at linux dot vnet dot ibm dot com 2009-05-08
17:04 ---
Created an attachment (id=17830)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17830&action=view)
X86_64 example code
This code was compiled with an x86_64 compiler with the -O3 -msse3 options.
--- Comment #3 from meissner at linux dot vnet dot ibm dot com 2009-05-08
17:03 ---
Created an attachment (id=17829)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17829&action=view)
Powerpc example code
This code was compiled with -O3 -maltivec.
--
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--- Comment #2 from meissner at linux dot vnet dot ibm dot com 2009-05-08
17:02 ---
Created an attachment (id=17828)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17828&action=view)
Replacement test case that doesn't need -DTYPE to show the bug
Replacement test case.
--
meiss
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