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* [Bug other/17105] New: Opportunity to improve aliasing analysis
@ 2004-08-19 14:59 gcc-bugzilla at gcc dot gnu dot org
  2004-08-19 15:18 ` [Bug tree-optimization/17105] " pinskia at gcc dot gnu dot org
  0 siblings, 1 reply; 2+ messages in thread
From: gcc-bugzilla at gcc dot gnu dot org @ 2004-08-19 14:59 UTC (permalink / raw)
  To: gcc-bugs

Description:
A non-optimal code sequence is illustraded.    Duplicate using gcc 3.5 and
command line:

gcc -O3 -m64 -c test.c


Testcase:
static int s1, s2;
int *p;

void foo ()
{

  s1 = 1;
  *p = 2;
  /* Shouldn't have to reload s1 here. It has not had its
     address taken so it shouldn't be aliased to *p. */
  s2 = s1;

}

Assembly:
.foo:
      ld 9,.LC1@toc(2)
      li 0,1
      ld 10,.LC0@toc(2)
      ld 11,0(9)
      li 9,2
      stw 0,0(10)
      stw 9,0(11)
      ld 8,.LC2@toc(2)
      lwz 0,0(10)  <--- reload is unnecessary.
      stw 0,0(8)
      blr



-- 
           Summary: Opportunity to improve aliasing analysis
           Product: gcc
           Version: 3.5.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P1
         Component: other
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: steinmtz at us dot ibm dot com
                CC: gcc-bugs at gcc dot gnu dot org,steinmtz at us dot ibm
                    dot com
 GCC build triplet: powerpc64-linux
  GCC host triplet: powerpc64-linux
GCC target triplet: powerpc64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17105


^ permalink raw reply	[flat|nested] 2+ messages in thread
* [Bug tree-optimization/17105] Opportunity to improve aliasing analysis
  2004-08-19 14:59 [Bug other/17105] New: Opportunity to improve aliasing analysis gcc-bugzilla at gcc dot gnu dot org
@ 2004-08-19 15:18 ` pinskia at gcc dot gnu dot org
  0 siblings, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-08-19 15:18 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From pinskia at gcc dot gnu dot org  2004-08-19 15:18 -------
Already fixed in a newer version of 3.5.0.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
          Component|other                       |tree-optimization
           Keywords|                            |missed-optimization
         Resolution|                            |FIXED
   Target Milestone|---                         |3.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17105


^ permalink raw reply	[flat|nested] 2+ messages in thread
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2004-08-19 14:59 [Bug other/17105] New: Opportunity to improve aliasing analysis gcc-bugzilla at gcc dot gnu dot org
2004-08-19 15:18 ` [Bug tree-optimization/17105] " pinskia at gcc dot gnu dot org

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