[Bug rtl-optimization/37471] Move invariant pulls too many cmps out of a loop

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37471

--- Comment #7 from Andrew Pinski  ---
I Notice LLVM does similarly on this testcase too.

[Bug rtl-optimization/37471] Move invariant pulls too many cmps out of a loop

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37471

Andrew Pinski  changed:

   What|Removed |Added

   Severity|normal  |enhancement
   Last reconfirmed|2015-11-22 00:00:00 |2021-12-18

[Bug rtl-optimization/37471] Move invariant pulls too many cmps out of a loop

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37471

Segher Boessenkool  changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
   Last reconfirmed||2015-11-22
 CC||segher at gcc dot gnu.org
 Ever confirmed|0   |1
  Known to fail||4.8.3, 4.9.3, 6.0

--- Comment #6 from Segher Boessenkool  ---
Oh wow.

... Still happens with trunk.  Confirmed.

[Bug rtl-optimization/37471] Move invariant pulls too many cmps out of a loop

[pinskia at gcc dot gnu dot org]

--- Comment #3 from pinskia at gcc dot gnu dot org  2010-03-02 18:53 ---
Still happens on the trunk.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37471

[Bug rtl-optimization/37471] Move invariant pulls too many cmps out of a loop

[steven at gcc dot gnu dot org]

--- Comment #4 from steven at gcc dot gnu dot org  2010-03-02 21:58 ---
Can you post the output .s of gcc, and the .s you expect?


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steven at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37471

[Bug rtl-optimization/37471] Move invariant pulls too many cmps out of a loop

[pinskia at gcc dot gnu dot org]

--- Comment #5 from pinskia at gcc dot gnu dot org  2010-03-02 22:02 ---
It is pretty obvious from doing a cross build.  We get a couple sets of:
lwz 0,112(1)
rlwinm 0,0,4,0x
mtcrf 1,0
rlwinm 0,0,28,0x
beq 7,.L6

Which loads r0 from the stack and then puts it into a conditional register and
the branches.  Note the rlwinm's are there to shift the registers around to put
it into the correct location for the mtcrf.


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pinskia at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|WAITING |UNCONFIRMED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37471

[Bug rtl-optimization/37471] Move invariant pulls too many cmps out of a loop

[pinskia at gcc dot gnu dot org]

--- Comment #2 from pinskia at gcc dot gnu dot org  2008-09-21 00:32 ---
While looking a different bug dealing with invariant motion, I noticed that
estimate_reg_pressure_cost does not take into account the mode of the new
register.  This seems like a big issue.  Also init_set_costs always uses SImode
which is not a good representation of the register pressure in general.  


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37471

[Bug rtl-optimization/37471] Move invariant pulls too many cmps out of a loop

[pinskia at gcc dot gnu dot org]

--- Comment #1 from pinskia at gcc dot gnu dot org  2008-09-14 04:42 ---
Note this is not a regression as loop.c did the same.


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pinskia at gcc dot gnu dot org changed:

   What|Removed |Added

  Known to fail||4.0.0 3.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37471