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* [Bug tree-optimization/55738] New: missed memory store optimization.
@ 2012-12-19 12:11 pluto at agmk dot net
  2012-12-19 12:26 ` [Bug tree-optimization/55738] " rguenth at gcc dot gnu.org
  0 siblings, 1 reply; 2+ messages in thread
From: pluto at agmk dot net @ 2012-12-19 12:11 UTC (permalink / raw)
  To: gcc-bugs


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55738

             Bug #: 55738
           Summary: missed memory store optimization.
    Classification: Unclassified
           Product: gcc
           Version: 4.7.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: pluto@agmk.net


Created attachment 29006
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29006
testcase

please consider attached testcase and look into NetsValue::set asm code.
one of the result isn't optimal (2 memory stores).


^ permalink raw reply	[flat|nested] 2+ messages in thread
* [Bug tree-optimization/55738] missed memory store optimization.
  2012-12-19 12:11 [Bug tree-optimization/55738] New: missed memory store optimization pluto at agmk dot net
@ 2012-12-19 12:26 ` rguenth at gcc dot gnu.org
  0 siblings, 0 replies; 2+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-12-19 12:26 UTC (permalink / raw)
  To: gcc-bugs


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55738

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> 2012-12-19 12:25:49 UTC ---
Well - that's because values_ may point to *this and thus

                                au::BoundBit< 7 >( values_[ index ] ) = 1;

may alter it.  Remember values_ is a pointer to char *.

So it's not valid for GCC to CSE the load of values_ which means the
stores are not detected as redundant.


^ permalink raw reply	[flat|nested] 2+ messages in thread
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2012-12-19 12:11 [Bug tree-optimization/55738] New: missed memory store optimization pluto at agmk dot net
2012-12-19 12:26 ` [Bug tree-optimization/55738] " rguenth at gcc dot gnu.org

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