[Bug tree-optimization/59660] We fail to optimize common boolean checks pre-inlining

[rguenther at suse dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59660

--- Comment #3 from rguenther at suse dot de <rguenther at suse dot de> ---
On Tue, 7 Jan 2014, hubicka at ucw dot cz wrote:

> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59660
> 
> --- Comment #2 from Jan Hubicka <hubicka at ucw dot cz> ---
> > I have noticed these, too (-Og is pessimzed by them).  The pattern is generated
> > by gimplifying.
> 
> I wondered why we can't simply update gimplifier to not produce them?
> (this is what I wanted to look into today, it seems pretty common pattern
> confusing inliner).
> For sure we should better also handle it either in cfg-cleanup or copyprop
> for cases that arrise as a result of other optimizations, but it seems it
> would speed things up if we did not wrap each predicate calls in its own three
> BBs.

Not all testcases can be handled at gimplification time IIRC.  Which
means "testcases welcome" first, so we can look at them individually.