Re: glibc-2.1 upgrade headaches. Any ideas??

Horst von Brand (vonbrand@sleipnir.valparaiso.cl)
Sun, 07 Mar 1999 13:48:44 -0400


CaT <cat@zip.com.au> said:

[...]

> I'd use -O6 but I can't find any info on what the hell this does
> as far as optimisation goes.

Look at your nearby gcc info entry.

Note that optimization levels beyond -O2 are _not_ recomended for the
kernel, on stock gcc/egcs -O3 and up enable automatic inlining, and part of
the kernel relies (mostly for performance, but sometimes also for
correctness) on certain functions _not_ to be inlined. Besides, this just
bloats the kernel for no good reason. pgcc is another matter, as the
meaning on the optimization levels was reworked there AFAIK.

> And is -fomit-frame-pointer a workaround for a bug in some implimentations
> of -O2

No, it's a separate optimization that precludes debugging. That's why it is
a separate flag. OTOH, -fno-strength-reduce is a workaround for a bug in
gcc-2.7.2.x.

Please RTFMs!

-- 
Horst von Brand                             vonbrand@sleipnir.valparaiso.cl
Casilla 9G, Viņa del Mar, Chile                               +56 32 672616

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