Compiler optimizing

David Jensen djensen at
Sun Feb 13 09:04:16 PST 2005

Ken Moffat wrote:
>  Most of us run varied workloads, or have old hardware that doesn't
> offer very many flags to tweak, or are unable to keep testing to get
> reliable and meaningful data to prove that our favourite options really
> make a difference.  People will willingly tell you their favourite
> options, but many of them will be deluding themselves :-(
> Ken

My big gripe is the -funroll-loops. Libpng for example uses it. 'Sed'ing 
the makefile.linux to -fomit-frame-pointer instead gives a 40% reduction 
in lib size and a 3% speed increase on my harware. ymmv

OT: libpng
Has anyone tried using the makefile.gcmmx instead?  It appears using 
that make builds mmx assembler routines for progressive reads that are 
otherwise disabled.  I assume this would be used by web browsers?  I 
messed with it, examples are in contrib/gregbook.  I did not install it 
and never tried it while browsing.  Anyone else looked?

David Jensen

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