[Bug tree-optimization/82604] [8 Regression] SPEC CPU2006 410.bwaves ~50% performance regression with trunk@253679 when ftree-parallelize-loops is used

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82604

--- Comment #2 from amker at gcc dot gnu.org ---
(In reply to Richard Biener from comment #1)
> I suppose loop distribution inserted a version copy turning this into a
> non-perfect nest for outer loops and thus disabling autopar there.
> 
> What probably makes sense is to run autoparallelization earlier or to try
Given passes like split/distribution/interchange are not to help
GRAPHITE/autopar, another choice is to push them later after GRAPHITE and
autopar?

> -fparallelize-loops-all (using ISL dependence analysis).
> 
> Just guesses of course, autopar isn't one of our most elaborate passes...