--- Additional Comments From kenner at vlsi1 dot ultra dot nyu dot edu
2005-02-10 18:12 ---
Subject: Re: [4.0 Regression] Poor quality code after loop unrolling.
It's been about a decade since I looked at cse vs autoincrements, so
the details have faded from memory. [The origi
--- Additional Comments From law at redhat dot com 2005-02-10 18:01 ---
Subject: Re: [4.0 Regression] Poor quality
code after loop unrolling.
On Thu, 2005-02-10 at 12:12 +0100, Zdenek Dvorak wrote:
> > In comment #3 Zdenek said "Possibly even better would be to add generation
>
--- Additional Comments From rakdver at atrey dot karlin dot mff dot cuni
dot cz 2005-02-10 11:12 ---
Subject: Re: [4.0 Regression] Poor quality code after loop unrolling.
> In comment #3 Zdenek said "Possibly even better would be to add generation of
> autoincrements to loop optimize
--- Additional Comments From steven at gcc dot gnu dot org 2005-02-10
11:02 ---
In comment #3 Zdenek said "Possibly even better would be to add generation of
autoincrements to loop optimizer, but this would require fixing cse so that it
handles them correctly." Zdenek, can you elabora
--- Additional Comments From rakdver at atrey dot karlin dot mff dot cuni
dot cz 2005-01-24 13:20 ---
Subject: Re: [4.0 Regression] Poor quality code after loop unrolling.
> Zdenek, is this still a regression, or are your suggestions from
> comment #12 only enhancements?
I think it
--- Additional Comments From steven at gcc dot gnu dot org 2005-01-21
14:06 ---
Zdenek, is this still a regression, or are your suggestions from
comment #12 only enhancements?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19078
--- Additional Comments From rakdver at gcc dot gnu dot org 2004-12-25
22:58 ---
Not closing the bug yet. There are futher issues; at least
-- we might want to be able to somehow determine whether splitting ivs is
profittable, instead of doing it unconditionally
-- we might want to im
--- Additional Comments From cvs-commit at gcc dot gnu dot org 2004-12-25
22:54 ---
Subject: Bug 19078
CVSROOT:/cvs/gcc
Module name:gcc
Changes by: [EMAIL PROTECTED] 2004-12-25 22:53:55
Modified files:
gcc: ChangeLog tree-ssa-loop-ivopts.c
Lo
--- Additional Comments From pcarlini at suse dot de 2004-12-25 20:32
---
Zdenek, sorry, is your patch in? I think Rth approved it!
http://gcc.gnu.org/ml/gcc-patches/2004-12/msg01613.html
Thanks.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19078
--- Additional Comments From pinskia at gcc dot gnu dot org 2004-12-22
16:45 ---
(In reply to comment #6)
> ;) Well, many people believe I look too *often* at microbenchmarks... ;)
Also sometimes micro benchmarks come from bigger code and shows up in the
profile as the hot loop.
--
--- Additional Comments From rakdver at gcc dot gnu dot org 2004-12-20
18:44 ---
Patch:
http://gcc.gnu.org/ml/gcc-patches/2004-12/msg01554.html
--
What|Removed |Added
--- Additional Comments From pcarlini at suse dot de 2004-12-20 15:22
---
More seriously, I think that we (the libstdc++-v3 people) should more carefully
test the effect of the new optimizations on std::algorithm: indeed, we are
talking
about benchmarks, not pointless microbenchmarks: s
--- Additional Comments From pcarlini at suse dot de 2004-12-20 15:13
---
;) Well, many people believe I look too *often* at microbenchmarks... ;)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19078
--- Additional Comments From steven at gcc dot gnu dot org 2004-12-20
15:04 ---
And, Paolo, when was the last time you looked at microbenchmarks? ;-)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19078
--- Additional Comments From pcarlini at suse dot de 2004-12-19 22:11
---
Thanks Zdenek. Very frankly, I'm somewhat surprised that we are noticing only
relatively late these problems: such loops seem *so* simple and common...
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19078
--- Additional Comments From rakdver at gcc dot gnu dot org 2004-12-19
22:04 ---
With minor adjustment in ivopts, we get the same code as in 3.3 with fno-split-
ivs-in-unroller, and more reasonably looking code without; I'm testing the
patch just now.
Of course we cannot have autoincre
--- Additional Comments From rakdver at gcc dot gnu dot org 2004-12-19
19:41 ---
Unroller splits the induction variables, so that the final code looks basically
like
if (a[0] == 2)
return a;
if (a[1] == 2)
return a + 4;
if (a[2] == 2)
return a + 8;
...
if (a[7] == 2)
return a +
--- Additional Comments From pinskia at gcc dot gnu dot org 2004-12-19
13:23 ---
In 3.3.2, the main loop is:
L7:
lwz r6,0(r9)
cmpwi cr0,r6,2
beq- cr0,L1
lwzu r7,4(r9)
cmpwi cr0,r7,2
beq- cr0,L1
lwzu r8,4(r9)
cmpwi cr0,r8,2
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