g++ optimizer report?

Yue K. Li yue.kevin.li@gmail.com
Mon Feb 8 08:07:00 GMT 2010


Hi, John,

On Wed, Feb 3, 2010 at 6:32 AM, John (Eljay) Love-Jensen
<eljay@adobe.com> wrote:
> Hi Yue,
>
> You can get a list of toggle-able optimization flags like this:
>
> touch Empty.cpp
> gcc -O2 -fverbose-asm -S Empty.cpp -o O2.s
> gcc -O3 -fverbose-asm -S Empty.cpp -o O3.s
>
> However, that will not tell you what non-toggle-able optimizations are enabled, since -O2 enables many optimizations that are not controlled by command line flags.  And -O3 enables a few more, as I understand it.
>
  This is interesting, and works.

> Nor will that tell you what optimization(s) were applied to a particular code segment.
>
   Ok, then that's fine. Thank you very much!

Yue



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