[Bug tree-optimization/57318] [4.9 Regression] optimizer takes several seconds on nested loops

[hubicka at ucw dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57318

--- Comment #7 from Jan Hubicka <hubicka at ucw dot cz> ---
> URL: http://gcc.gnu.org/viewcvs?rev=199140&root=gcc&view=rev
> Log:
> 2013-05-21  Richard Biener  <rguenther@suse.de>
> 
>     PR tree-optimization/57318
>     * tree-ssa-loop-ivcanon.c (tree_estimate_loop_size): Do not
>     estimate stmts with side-effects as likely eliminated.
> 
> Modified:
>     trunk/gcc/ChangeLog
>     trunk/gcc/tree-ssa-loop-ivcanon.c
> 
> Fixed - latent on the branch though.

Hmm, this heuristic was sort of intended (inliner makes same trick)
We anticipate that making the array stores explicit will enable SRA & stuff.
But since then I made inliner to asume the 50% probability of optimizing
these away that works better.

Did you measure runtime effect of this? (we will see in SPEC graph soon
I guess)

Honza