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* [Bug target/17959] New: -mpowerpc64 can cause worse code than without it
@ 2004-10-12 23:01 pinskia at gcc dot gnu dot org
  2004-10-12 23:03 ` [Bug target/17959] " pinskia at gcc dot gnu dot org
  2004-11-28  8:27 ` amodra at bigpond dot net dot au
  0 siblings, 2 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-10-12 23:01 UTC (permalink / raw)
  To: gcc-bugs

unsigned long long div16(unsigned long long n) { return n / 16; }

Without -mpowerpc64:
_div16:
        slwi r0,r3,28
        srwi r4,r4,4
        or r4,r0,r4
        srwi r3,r3,4
        blr

With:
_div16:
        li r0,0
        rldimi r0,r3,32,0
        rldimi r0,r4,0,32
        srdi r4,r0,4
        srdi r3,r0,36
        blr

-- 
           Summary: -mpowerpc64 can cause worse code than without it
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc-darwin


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17959


^ permalink raw reply	[flat|nested] 5+ messages in thread
* [Bug target/17959] -mpowerpc64 can cause worse code than without it
  2004-10-12 23:01 [Bug target/17959] New: -mpowerpc64 can cause worse code than without it pinskia at gcc dot gnu dot org
@ 2004-10-12 23:03 ` pinskia at gcc dot gnu dot org
  2004-11-28  8:27 ` amodra at bigpond dot net dot au
  1 sibling, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-10-12 23:03 UTC (permalink / raw)
  To: gcc-bugs



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-10-12 23:03:57
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17959


^ permalink raw reply	[flat|nested] 5+ messages in thread
* [Bug target/17959] -mpowerpc64 can cause worse code than without it
  2004-10-12 23:01 [Bug target/17959] New: -mpowerpc64 can cause worse code than without it pinskia at gcc dot gnu dot org
  2004-10-12 23:03 ` [Bug target/17959] " pinskia at gcc dot gnu dot org
@ 2004-11-28  8:27 ` amodra at bigpond dot net dot au
  1 sibling, 0 replies; 5+ messages in thread
From: amodra at bigpond dot net dot au @ 2004-11-28  8:27 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From amodra at bigpond dot net dot au  2004-11-28 08:27 -------
powerpc-linux too.  3.4 is even worse due to needlessly setting up a stack frame.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
 GCC target triplet|powerpc-darwin              |powerpc-*-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17959


^ permalink raw reply	[flat|nested] 5+ messages in thread
* [Bug target/17959] -mpowerpc64 can cause worse code than without it
       [not found] <bug-17959-6528@http.gcc.gnu.org/bugzilla/>
  2006-03-30 17:47 ` sayle at gcc dot gnu dot org
@ 2006-03-30 21:35 ` roger at eyesopen dot com
  1 sibling, 0 replies; 5+ messages in thread
From: roger at eyesopen dot com @ 2006-03-30 21:35 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #3 from roger at eyesopen dot com  2006-03-30 21:35 -------
This is now be fixed on mainline.  With -mpowerpc64, we now generate:

_div16:
        rldimi 3,4,0,32
        srdi 4,3,4
        srdi 3,3,36
        blr



-- 

roger at eyesopen dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17959


^ permalink raw reply	[flat|nested] 5+ messages in thread
* [Bug target/17959] -mpowerpc64 can cause worse code than without it
       [not found] <bug-17959-6528@http.gcc.gnu.org/bugzilla/>
@ 2006-03-30 17:47 ` sayle at gcc dot gnu dot org
  2006-03-30 21:35 ` roger at eyesopen dot com
  1 sibling, 0 replies; 5+ messages in thread
From: sayle at gcc dot gnu dot org @ 2006-03-30 17:47 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #2 from sayle at gcc dot gnu dot org  2006-03-30 17:47 -------
Subject: Bug 17959

Author: sayle
Date: Thu Mar 30 17:47:48 2006
New Revision: 112543

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=112543
Log:

        PR target/17959
        * expr.c (emit_group_store):  Optimize group stores into a pseudo
        register by using a paradoxical subreg to initialize the destination
        if the first or last member of the group specifies a "low part".


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/expr.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17959


^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2006-03-30 21:35 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-10-12 23:01 [Bug target/17959] New: -mpowerpc64 can cause worse code than without it pinskia at gcc dot gnu dot org
2004-10-12 23:03 ` [Bug target/17959] " pinskia at gcc dot gnu dot org
2004-11-28  8:27 ` amodra at bigpond dot net dot au
     [not found] <bug-17959-6528@http.gcc.gnu.org/bugzilla/>
2006-03-30 17:47 ` sayle at gcc dot gnu dot org
2006-03-30 21:35 ` roger at eyesopen dot com

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