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Re: -O2 versus -O1 (Was: Re: GCSE store motion)
- From: Geert Bosch <bosch at gnat dot com>
- To: Jan Hubicka <jh at suse dot cz>
- Cc: Robert Dewar <dewar at gnat dot com>, dberlin at dberlin dot org,mark at codesourcery dot com, roger at eyesopen dot com, aj at suse dot de,davem at redhat dot com, gcc at gcc dot gnu dot org, rth at redhat dot com
- Date: Thu, 16 May 2002 10:48:32 -0400
- Subject: Re: -O2 versus -O1 (Was: Re: GCSE store motion)
On Thursday, May 16, 2002, at 10:07 , Jan Hubicka wrote:
> On the other hand at -O2 we do some bits that are not that expensive
> and may come to -O1 category. I would guess for:
>
> flag_optimize_sibling_calls = 1;
> flag_rename_registers = 1;
> flag_caller_saves = 1;
> flag_force_mem = 1;
> flag_regmove = 1;
> flag_strict_aliasing = 1;
> flag_reorder_blocks = 1;
> flag_reorder_functions = 1;
A second important goal for -O1 is to keep code as debuggable as
possible. This rules out at least the sibling calls optimization, but
probably others as well.
-Geert