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Re: [3.2 PATCH] PR c/761: Document command line options
- From: Fergus Henderson <fjh at cs dot mu dot OZ dot AU>
- To: Roger Sayle <roger at eyesopen dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Wed, 23 Oct 2002 14:05:45 +1000
- Subject: Re: [3.2 PATCH] PR c/761: Document command line options
- References: <Pine.BSF.4.44.0210210657020.76061-100000@naos.dbai.tuwien.ac.at> <Pine.LNX.4.33.0210222055100.17057-100000@www.eyesopen.com>
On 22-Oct-2002, Roger Sayle <roger@eyesopen.com> wrote:
>
> + @item -feliminate-dwarf2-dups
> + @opindex feliminate-dwarf2-dups
> + Compress DWARF2 debugging information by eliminating duplicated
> + information about each symbol. This option only makes sense when
> + generating DWARF2 debugging information with @option{-gdwarf-2}.
Why would you ever want to *not* enable this option?
> + @item -fno-branch-count-reg
> + @opindex fno-branch-count-reg
> + Do not use ``decrement and branch'' instructions on a count register,
> + but instead generate a sequence of instructions that decrement a
> + register, compare it against zero, then branch based upon the result.
> + This option is only meaningful on architectures that support such
> + instructions, which include x86, PowerPC, IA-64 and S/390.
Likewise, why would you want to use this option?
(If the answer is that it might improve performance,
why can't the compiler just do the right thing in the first place?)
--
Fergus Henderson <fjh@cs.mu.oz.au> | "I have always known that the pursuit
The University of Melbourne | of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh> | -- the last words of T. S. Garp.