[3.2 PATCH] PR c/761: Document command line options

Fergus Henderson fjh@cs.mu.OZ.AU
Tue Oct 22 21:05:00 GMT 2002


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.



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