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dcstimm
Guru
Joined: 19 Jun 2002
Posts: 321
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 Posted: Wed Jul 17, 2002 11:40 pm Post subject: gcc flags |
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hi I have a dual p3 machine I want gcc to have the best flags possible for my machine.
this is what i currently have (which I know is default)
CHOST="i686-pc-linux-gnu"
CFLAGS="-mcpu=i686 -O3 -pipe"
CXXFLAGS="-mcpu=i686 -O3 -pipe"
can you tell me why there isnt a option for a more p3 oriented option in the make.conf?
why not use some options like this?
-O3 -march=pentium3 -fomit-frame-pointer -pipe -mmmx -msse
(of course I dont know how to set them up in the format above)
could these be included in the make.conf file so when I build gentoo I can have it optimized for my hardware?
thanks... |
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proxy
Apprentice
Joined: 20 Apr 2002
Posts: 253
Location: Chantilly, VA
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| Posted: Thu Jul 18, 2002 3:09 am Post subject: |
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err, just put whatever you want there..that's the point. gentoo supplies you with _examples_ which are safe for more or less every program, if you want ot expand on that...feel free. That's the beuty of gentoo.
my CFLAGS looks like this:
| Code: | CHOST="i686-pc-linux-gnu"
CFLAGS="-march=i686 -O3 -pipe -fomit-frame-pointer -fstrength-reduce -fexpensive-optimizations -frerun-cse-after-loop -frerun-loop-opt -malign-functions=4"
CXXFLAGS=${CFLAGS} |
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citizen428
Retired Dev
Joined: 10 Jun 2002
Posts: 317
Location: Vienna, Austria
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| Posted: Thu Jul 18, 2002 10:47 am Post subject: |
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Hi Proxy!
-O3 includes all the options you specify seperately.
| Code: |
-O: defer_pop, thread_jumps, delayed_branch, omit_frame_pointer, opt_reg_use, reduce_index_givs
-O2: cse_follow_jumps, cse_skip_blocks, gcse, expensive_optimizations, strength_reduce, rerun_cse_after_loop, rerun_loop_opt, caller_saves, force_mem, regmove, schedule_insns, schedule_insns_after_reload
-O3: inline_functions, jump_back, copy_prop, compare_elim, sftwr_pipe, reg_reg_copy_opt, peep_spills, replace_stack_mem, opt_jumps_out, replace_mem, correct_cse_mistakes, push_load_into_loop, replace_reload_regs, sign_extension_elim, lift_stores
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They're cumulative, so -O2 includes all of -O, as -O3 includes all of -0 and -O2.
Just to save you some typing. 
http://industrial-linux.org/pgcc-options.html
See also man gcc, Optimization Options. |
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