[Bug tree-optimization/45622] Suboptimal code generation on arm
ramana at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Mon Oct 4 09:15:00 GMT 2010
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45622
Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |WAITING
Last reconfirmed| |2010.10.04 09:15:04
CC| |ramana at gcc dot gnu.org
Ever Confirmed|0 |1
--- Comment #2 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> 2010-10-04 09:15:04 UTC ---
(In reply to comment #0)
> Vorbis author, Timothy Terriberry, was complaining about gcc inefficiency on
> arm, so I asked him write it up in case it would be of use to gcc devs to
> improve gcc. Is this a useful?
>
The description is rather useful but it would be good to have a copy of the
pre-processed file as HP says in Comment #2. It also helps so that the bug
report is self-consistent .
What command line options are being used ? i.e. what are the architecture
specific flags ( -march= ? -mfpu= ? -mfloat-abi=? ? ) . If you use --save-temps
you can pickup the .i file .
>
> This the result of using arm-none-linux-gnueabi-gcc (Gentoo 4.5.0 p1.1) 4.5.0
> with -O3 -fomit-frame-pointer -funroll-loops (this last makes a fairly big
> difference on x86, and so is part of the default flags for the library).
-fomit-frame-pointer is typically not required on ARM. It's one of the ABI's
that originally never had a frame pointer in normal functions and thus removing
the frame pointer doesn't make sense.
cheers
Ramana
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