[Bug c/36598] Failed optimisation of return of struct argment in memcpy-1.c

[joseph at codesourcery dot com]

--- Comment #1 from joseph at codesourcery dot com  2008-06-22 13:32 ---
Subject: Re:   New: Failed optimisation of return of struct
 argment in memcpy-1.c

On Sun, 22 Jun 2008, hutchinsonandy at gcc dot gnu dot org wrote:

 Testcase gcc.dg/memcpy-1.c fails on AVR target.

Have you looked at bug 31677 which suggests using the option --param 
sra-max-structure-size=32?  If that works for AVR, you could submit a 
patch to add it to the testcase for all targets.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36598

[Bug c/36598] Failed optimisation of return of struct argment in memcpy-1.c

[hutchinsonandy at gcc dot gnu dot org]

--- Comment #2 from hutchinsonandy at gcc dot gnu dot org  2008-06-22 14:33 
---
Thanks for information

--param sra-max-structure-size=32 does indeed remove test failure and produces
optimal code.

But changing the testcase does not remove the optimization problem - unless
sra-max-structure-size was always used. So there is problem somewhere else to
fix.

See also:

http://gcc.gnu.org/ml/gcc-patches/2007-12/msg01144.html

Andy


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36598

[Bug c/36598] Failed optimisation of return of struct argment in memcpy-1.c

[rguenth at gcc dot gnu dot org]

--- Comment #3 from rguenth at gcc dot gnu dot org  2008-06-22 14:50 ---
This is really not a task for SRA but for struct copy propagation (which we
do not do).  See PR14295.

As this testcase was for SRA you can either XFAIL it for avr or see if the
cost metrics need adjustment.


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rguenth at gcc dot gnu dot org changed:

   What|Removed |Added

  BugsThisDependsOn||14295


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36598

[Bug c/36598] Failed optimisation of return of struct argment in memcpy-1.c

[hutchinsonandy at gcc dot gnu dot org]

--- Comment #4 from hutchinsonandy at gcc dot gnu dot org  2008-06-22 16:11 
---
Quite possibly due to cost metrics. They are far from ideal.

Will mark test XFAIL until we can investigate and fix.


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hutchinsonandy at gcc dot gnu dot org changed:

   What|Removed |Added

 CC||eric dot weddington at atmel
   ||dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36598