Analyzing Optimization: What's New in 3.4?

[Scott Robert Ladd]

Andrew Pinski wrote:
> With the new loop unroller comes an option called -fpeel-loops which you 
> might want to try.

I'll add this to my list

> Note: -funit-at-a-time is enabled by default at -O3 and above.

I'm compiling with -O1 and enabling specific flags to compare 
interactions and generated code performance; I've already added 
-funit-at-a-time to the mix.

> Another thing you want want to try is intermodule optimizations (only 
> works for C code though).

For specific reasons, my current tests exist in singular source files. 
That will change once my methods have stabilized.

> No, but you can benchmark the tree-ssa branch which is replacing these 
> options.

I'll look at tree-ssa once I've got the 3.4 "optimization optimizer" 
working.

> -fnew-ra is a good option to benchmark (it might slow down the code 
> though).
> -ftracer is also sometimes a good option to use.

I'll add these as well.

Thanks for the feedback.

-- 
Scott Robert Ladd
Coyote Gulch Productions (http://www.coyotegulch.com)
Software Invention for High-Performance Computing