[Vorbis-dev] [patch] libvorbis + gcc4
cloos at jhcloos.com
Mon Aug 1 17:48:43 PDT 2005
>>>>> "j" == j <j at v2v.cc> writes:
j> the question is now which part of -O3(which -O20 is in the end)
j> causes this increase in vorbis and is it a bug in vorbis or in
In gcc3 -O3 only adds -finline-functions and -frename-registers
to -O2. As of gcc 4.0.0 it adds -finline-functions, -funswitch-
loops and -fgcse-after-reload.
Since inline-functions wasn't causing the problem before gcc4,
it probably isn't now either. I'd bet on -funswitch-loops.
This is what gcc.info has to say about that option:
| Move branches with loop invariant conditions out of the loop,
| with duplicates of the loop on both branches (modified according
| to result of the condition).
But give each possibility a test compile to see for sure.
Incidently, was there any performance difference between the
James H. Cloos, Jr. <cloos at jhcloos.com>
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