[Bug rtl-optimization/43286] Missed related value optimization in cse.c

[steven at gcc dot gnu dot org]

--- Comment #6 from steven at gcc dot gnu dot org  2010-03-18 08:27 ---
Reopening...


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steven at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|RESOLVED|REOPENED
 Resolution|INVALID |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43286

[Bug rtl-optimization/43286] Missed related value optimization in cse.c

[steven at gcc dot gnu dot org]

--- Comment #7 from steven at gcc dot gnu dot org  2010-03-18 08:29 ---
...to close as dup of bug 39871

*** This bug has been marked as a duplicate of 39871 ***


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steven at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|REOPENED|RESOLVED
 Resolution||DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43286

[Bug rtl-optimization/43286] Missed related value optimization in cse.c

[carrot at google dot com]

--- Comment #5 from carrot at google dot com  2010-03-18 03:52 ---
In this case arm_arm_address_cost does the right thing. The problem is in
function should_replace_address.

When two addresses have same address cost, we choose the one with higher rtx
cost. The reason is That has the potential of eliminating the most insns
without additional costs. But when two addresses have the same rtx cost, they
also have the potential to eliminate a previous definition. Just as
demonstrated by this test case.

One of the candidate is

old_rtx
(plus:SI (reg/v/f:SI 133 [ saveArea ])
(const_int 8 [0x8]))

new_rtx
(plus:SI (reg/v/f:SI 140 [ fp ])
(const_int -8 [0xfff8]))

After all of these addresses being replaced, instruction A can be removed.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43286

[Bug rtl-optimization/43286] Missed related value optimization in cse.c

[ramana at gcc dot gnu dot org]

--- Comment #3 from ramana at gcc dot gnu dot org  2010-03-10 14:49 ---
Confirmed but do we expect this to be done in CSE . IIUC, shouldn't this be a
part of fwprop handling addresses rather than doing this in CSE ? 


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ramana at gcc dot gnu dot org changed:

   What|Removed |Added

   Severity|normal  |enhancement
 Status|UNCONFIRMED |NEW
 Ever Confirmed|0   |1
   Last reconfirmed|-00-00 00:00:00 |2010-03-10 14:49:38
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43286

[Bug rtl-optimization/43286] Missed related value optimization in cse.c

[steven at gcc dot gnu dot org]

--- Comment #4 from steven at gcc dot gnu dot org  2010-03-10 16:21 ---
Another arm_arm_address_cost problem, dup of something I'm not even going to
try to find.

Until ARM or an ARM maintainer cares (or Google folks stop filing and start
fixing bugs), we don't need more reports of the same problem


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steven at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution||INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43286

[Bug rtl-optimization/43286] Missed related value optimization in cse.c

[carrot at google dot com]

--- Comment #1 from carrot at google dot com  2010-03-08 08:28 ---
Created an attachment (id=20040)
 -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20040action=view)
test case


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43286

[Bug rtl-optimization/43286] Missed related value optimization in cse.c

[carrot at google dot com]

--- Comment #2 from carrot at google dot com  2010-03-08 08:32 ---
The command line options are: -march=armv7-a -O2 -fpic


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43286