new patches using -fopt-info (issue5294043)

Andi Kleen andi@firstfloor.org
Thu Oct 20 00:03:00 GMT 2011


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



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