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Re: new patches using -fopt-info (issue5294043)
OK. I'll keep it in mind. We probably won't include all the messages
in one shot. But we do plan to add all of them finally because we
believe they are helpful for tracking the performance.
-Rong
On Wed, Oct 19, 2011 at 4:33 PM, Andi Kleen <andi@firstfloor.org> wrote:
> xur@google.com (Rong Xu) writes:
>
>> After some off-line discussion, we decided to use a more general approach
>> to control the printing of optimization messages/warnings. We will
>> introduce a new option -fopt-info:
>> ?* fopt-info=0 or fno-opt-info: no message will be emitted.
>> ?* fopt-info or fopt-info=1: emit important warnings and optimization
>> ? ?messages with large performance impact.
>> ?* fopt-info=2: warnings and optimization messages targeting power users.
>> ?* fopt-info=3: informational messages for compiler developers.
>
> It would be interested to have some warnings about missing SRA
> opportunities in =1 or =2. I found that sometimes fixing those can give a
> large speedup.
>
> Right now a common case that prevents SRA on structure field
> is simply a memset or memcpy.
>
> -Andi
>
>
> --
> ak@linux.intel.com -- Speaking for myself only
>