[Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3

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* [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3
       [not found] <bug-29274-4@http.gcc.gnu.org/bugzilla/>
@ 2011-06-27 12:12 ` rguenth at gcc dot gnu.org
  2011-06-27 16:20 ` [Bug middle-end/29274] [4.4/4.5 " bernds at gcc dot gnu.org
  2011-06-28 11:24 ` rguenth at gcc dot gnu.org
  2 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-06-27 12:12 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.6                       |4.4.7

--- Comment #15 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-06-27 12:11:59 UTC ---
4.3 branch is being closed, moving to 4.4.7 target.


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.4/4.5 Regression] not using mulsidi3
       [not found] <bug-29274-4@http.gcc.gnu.org/bugzilla/>
  2011-06-27 12:12 ` [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3 rguenth at gcc dot gnu.org
@ 2011-06-27 16:20 ` bernds at gcc dot gnu.org
  2011-06-28 11:24 ` rguenth at gcc dot gnu.org
  2 siblings, 0 replies; 11+ messages in thread
From: bernds at gcc dot gnu.org @ 2011-06-27 16:20 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274

Bernd Schmidt <bernds at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bernds at gcc dot gnu.org
      Known to work|                            |
         Resolution|                            |FIXED
      Known to fail|                            |

--- Comment #16 from Bernd Schmidt <bernds at gcc dot gnu.org> 2011-06-27 12:53:20 UTC ---
Fixed in trunk, wontfix for the old trees, I'd think.


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.4/4.5 Regression] not using mulsidi3
       [not found] <bug-29274-4@http.gcc.gnu.org/bugzilla/>
  2011-06-27 12:12 ` [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3 rguenth at gcc dot gnu.org
  2011-06-27 16:20 ` [Bug middle-end/29274] [4.4/4.5 " bernds at gcc dot gnu.org
@ 2011-06-28 11:24 ` rguenth at gcc dot gnu.org
  2 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-06-28 11:24 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.4.7                       |4.6.0


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c/29274]  New: 4.1, 4.2 (possibly 4.0?) not using mulsidi3
@ 2006-09-28 16:43 eplondke at gmail dot com
  2009-03-31 19:46 ` [Bug middle-end/29274] [4.3/4.4/4.5 Regression] " jsm28 at gcc dot gnu dot org
                   ` (7 more replies)
  0 siblings, 8 replies; 11+ messages in thread
From: eplondke at gmail dot com @ 2006-09-28 16:43 UTC (permalink / raw)
  To: gcc-bugs

GCC 4.x tree optimization decides to put int values into long long int
temporaries.  When RTL expansion comes around, the expander sees only a DImode
multiply and so generates three SImode multiplies to deal with the problem.

GCC 3.x sees that the source values are SImode and uses mulsidi3 to generate
32x32->64 multiplies, which are much more efficient.  It also picks up the
accumulation.

(using -O3 for all compilations)

GCC 3.4 has an 84-byte stack frame, and a body of 372 instructions.
GCC 4.1 has a 1416-byte stack frame, and a body of 1668 instructions.
GCC 4.2 has a 1320-byte stack frame, and a body of 1565 instructions.

-- 
           Summary: 4.1, 4.2 (possibly 4.0?) not using mulsidi3
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: eplondke at gmail dot com
  GCC host triplet: x86_64-suse-linux
GCC target triplet: arm-unkown-elf

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3
  2006-09-28 16:43 [Bug c/29274] New: 4.1, 4.2 (possibly 4.0?) " eplondke at gmail dot com
@ 2009-03-31 19:46 ` jsm28 at gcc dot gnu dot org
  2009-08-04 12:41 ` rguenth at gcc dot gnu dot org
                   ` (6 subsequent siblings)
  7 siblings, 0 replies; 11+ messages in thread
From: jsm28 at gcc dot gnu dot org @ 2009-03-31 19:46 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #6 from jsm28 at gcc dot gnu dot org  2009-03-31 19:46 -------
Closing 4.2 branch.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[4.2/4.3/4.4/4.5 Regression]|[4.3/4.4/4.5 Regression] not
                   |not using mulsidi3          |using mulsidi3
   Target Milestone|4.2.5                       |4.3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3
  2006-09-28 16:43 [Bug c/29274] New: 4.1, 4.2 (possibly 4.0?) " eplondke at gmail dot com
  2009-03-31 19:46 ` [Bug middle-end/29274] [4.3/4.4/4.5 Regression] " jsm28 at gcc dot gnu dot org
@ 2009-08-04 12:41 ` rguenth at gcc dot gnu dot org
  2009-08-26 15:50 ` froydnj at gcc dot gnu dot org
                   ` (5 subsequent siblings)
  7 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2009-08-04 12:41 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #7 from rguenth at gcc dot gnu dot org  2009-08-04 12:27 -------
GCC 4.3.4 is being released, adjusting target milestone.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.4                       |4.3.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3
  2006-09-28 16:43 [Bug c/29274] New: 4.1, 4.2 (possibly 4.0?) " eplondke at gmail dot com
  2009-03-31 19:46 ` [Bug middle-end/29274] [4.3/4.4/4.5 Regression] " jsm28 at gcc dot gnu dot org
  2009-08-04 12:41 ` rguenth at gcc dot gnu dot org
@ 2009-08-26 15:50 ` froydnj at gcc dot gnu dot org
  2009-08-26 18:35 ` rguenth at gcc dot gnu dot org
                   ` (4 subsequent siblings)
  7 siblings, 0 replies; 11+ messages in thread
From: froydnj at gcc dot gnu dot org @ 2009-08-26 15:50 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #8 from froydnj at gcc dot gnu dot org  2009-08-26 15:50 -------
Even if the problems in expand are fixed, reassoc is still going to cause
problems with the original testcase.  From the dse1 dump:

  D.2474_14 = (long long int) vLo_11;
  D.2475_15 = (long long int) c1_6;
  D.2476_16 = D.2474_14 * D.2475_15;
  D.2477_19 = (long long int) c2_8;
  D.2478_20 = D.2474_14 * D.2477_19;

>From the reassoc1 dump right after:

  D.2474_14 = (long long int) vLo_11;
  D.2475_15 = (long long int) c1_6;
  D.2477_19 = (long long int) c2_8;
  D.2495_16 = D.2477_19 + D.2475_15;
  D.2495_20 = D.2495_16 * D.2474_14;

So we've traded a multiplication for an addition, but we've also made it
difficult to see that we could have used mulsidi3.


-- 

froydnj at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |froydnj at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3
  2006-09-28 16:43 [Bug c/29274] New: 4.1, 4.2 (possibly 4.0?) " eplondke at gmail dot com
                   ` (2 preceding siblings ...)
  2009-08-26 15:50 ` froydnj at gcc dot gnu dot org
@ 2009-08-26 18:35 ` rguenth at gcc dot gnu dot org
  2009-12-29 23:21 ` ramana at gcc dot gnu dot org
                   ` (3 subsequent siblings)
  7 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2009-08-26 18:35 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #9 from rguenth at gcc dot gnu dot org  2009-08-26 18:35 -------
Note that even for

  (long long)i * (long long)j * (long long)i

we can only use one mulsidi3, so promoting parts of the multiplications to
additions should be still beneficial.

I suppose we should detect widening multiply on the tree level before
re-association where it is beneficial (if the target doesn't have a native
wide multiplication).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3
  2006-09-28 16:43 [Bug c/29274] New: 4.1, 4.2 (possibly 4.0?) " eplondke at gmail dot com
                   ` (3 preceding siblings ...)
  2009-08-26 18:35 ` rguenth at gcc dot gnu dot org
@ 2009-12-29 23:21 ` ramana at gcc dot gnu dot org
  2010-04-22 10:12 ` rguenth at gcc dot gnu dot org
                   ` (2 subsequent siblings)
  7 siblings, 0 replies; 11+ messages in thread
From: ramana at gcc dot gnu dot org @ 2009-12-29 23:21 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #10 from ramana at gcc dot gnu dot org  2009-12-29 23:21 -------
*** Bug 42498 has been marked as a duplicate of this bug. ***


-- 

ramana at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |carrot at google dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3
  2006-09-28 16:43 [Bug c/29274] New: 4.1, 4.2 (possibly 4.0?) " eplondke at gmail dot com
                   ` (4 preceding siblings ...)
  2009-12-29 23:21 ` ramana at gcc dot gnu dot org
@ 2010-04-22 10:12 ` rguenth at gcc dot gnu dot org
  2010-04-22 11:26 ` bernds at gcc dot gnu dot org
  2010-05-22 18:24 ` rguenth at gcc dot gnu dot org
  7 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2010-04-22 10:12 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #12 from rguenth at gcc dot gnu dot org  2010-04-22 10:11 -------
Fixed for 4.6.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|3.4.2                       |3.4.2 4.6.0
            Summary|[4.3/4.4/4.5/4.6 Regression]|[4.3/4.4/4.5 Regression] not
                   |not using mulsidi3          |using mulsidi3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3
  2006-09-28 16:43 [Bug c/29274] New: 4.1, 4.2 (possibly 4.0?) " eplondke at gmail dot com
                   ` (5 preceding siblings ...)
  2010-04-22 10:12 ` rguenth at gcc dot gnu dot org
@ 2010-04-22 11:26 ` bernds at gcc dot gnu dot org
  2010-05-22 18:24 ` rguenth at gcc dot gnu dot org
  7 siblings, 0 replies; 11+ messages in thread
From: bernds at gcc dot gnu dot org @ 2010-04-22 11:26 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #13 from bernds at gcc dot gnu dot org  2010-04-22 11:26 -------
Subject: Bug 29274

Author: bernds
Date: Thu Apr 22 11:25:44 2010
New Revision: 158642

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=158642
Log:
        PR middle-end/29274
        * gcc.target/arm/wmul-1.c: New test.
        * gcc.target/arm/wmul-2.c: New test.


Added:
    trunk/gcc/testsuite/gcc.target/arm/wmul-1.c
    trunk/gcc/testsuite/gcc.target/arm/wmul-2.c
Modified:
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3
  2006-09-28 16:43 [Bug c/29274] New: 4.1, 4.2 (possibly 4.0?) " eplondke at gmail dot com
                   ` (6 preceding siblings ...)
  2010-04-22 11:26 ` bernds at gcc dot gnu dot org
@ 2010-05-22 18:24 ` rguenth at gcc dot gnu dot org
  7 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2010-05-22 18:24 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #14 from rguenth at gcc dot gnu dot org  2010-05-22 18:11 -------
GCC 4.3.5 is being released, adjusting target milestone.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.5                       |4.3.6


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274


^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2011-06-28 11:24 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <bug-29274-4@http.gcc.gnu.org/bugzilla/>
2011-06-27 12:12 ` [Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3 rguenth at gcc dot gnu.org
2011-06-27 16:20 ` [Bug middle-end/29274] [4.4/4.5 " bernds at gcc dot gnu.org
2011-06-28 11:24 ` rguenth at gcc dot gnu.org
2006-09-28 16:43 [Bug c/29274] New: 4.1, 4.2 (possibly 4.0?) " eplondke at gmail dot com
2009-03-31 19:46 ` [Bug middle-end/29274] [4.3/4.4/4.5 Regression] " jsm28 at gcc dot gnu dot org
2009-08-04 12:41 ` rguenth at gcc dot gnu dot org
2009-08-26 15:50 ` froydnj at gcc dot gnu dot org
2009-08-26 18:35 ` rguenth at gcc dot gnu dot org
2009-12-29 23:21 ` ramana at gcc dot gnu dot org
2010-04-22 10:12 ` rguenth at gcc dot gnu dot org
2010-04-22 11:26 ` bernds at gcc dot gnu dot org
2010-05-22 18:24 ` rguenth at gcc dot gnu dot org

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