[Bug rtl-optimization/27567] [4.0/4.1/4.2 Regression] __builtin_memcpy generates redundant stores/moves.

[pinskia at gcc dot gnu dot org]

--- Comment #2 from pinskia at gcc dot gnu dot org  2006-08-27 18:59 ---
Part of the problem here is that 4.0 removed addressof but that does not
explain why 3.4.0 could not do this optimization.
Maybe one of the problems is that we are no "lowering" memcpy at the tree level
into VCE (which should fix this one issue).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27567

[Bug rtl-optimization/27567] [4.0/4.1/4.2 Regression] __builtin_memcpy generates redundant stores/moves.

[rguenth at gcc dot gnu dot org]

--- Comment #1 from rguenth at gcc dot gnu dot org  2006-05-12 08:27 ---
f is marked addressable and assigned a stack slot.  That the stores are not
optimized away later is probably due to aliasing issues - an open-coded memcpy
must behave like the -fno-strict-aliasing case, so I guess we applied measures
to assure this and this prevents this optimization.  3.3 and 3.3-hammer can do
the optimization.


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rguenth at gcc dot gnu dot org changed:

   What|Removed |Added

 CC||rguenth at gcc dot gnu dot
   ||org, hubicka at gcc dot gnu
   ||dot org
 Status|UNCONFIRMED |NEW
  Component|other   |rtl-optimization
 Ever Confirmed|0   |1
   Keywords||missed-optimization
  Known to fail||3.4.6 4.0.3 4.1.0 4.2.0
  Known to work||3.3.6
   Last reconfirmed|-00-00 00:00:00 |2006-05-12 08:27:14
   date||
Summary|__builtin_memcpy generates  |[4.0/4.1/4.2 Regression]
   |redundant stores/moves. |__builtin_memcpy generates
   ||redundant stores/moves.
   Target Milestone|--- |4.0.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27567

[Bug rtl-optimization/27567] [4.0/4.1/4.2 Regression] __builtin_memcpy generates redundant stores/moves.

[mmitchel at gcc dot gnu dot org]

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mmitchel at gcc dot gnu dot org changed:

   What|Removed |Added

   Priority|P3  |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27567