RFR(S): Optimize main and post loop out when pre loop is found empty

[Roland Westrelin]

Hi Michael,

> Roland, in LoopTransform.cpp, in IdealLoopTree::remove_main_post_loops,
> Please remove the extra ; on line 2248.
> 
> Also, you might want to make the instances of _next->head and ..->as_CountedLoop() variables in that function to keep the number of dereferences and calls down.  May just returning on null and guarding on
> Is_CountedLoop(), then assigning a variable for as_Counted Loop within the guard.
> 
> Else it looks good.

Thanks for looking at this. I refactored the code following your suggestions.

Roland.

> 
> -Michael
> 
> -----Original Message-----
> From: hotspot-compiler-dev [mailto:hotspot-compiler-dev-bounces at openjdk.java.net] On Behalf Of Roland Westrelin
> Sent: Thursday, June 04, 2015 7:55 AM
> To: hotspot compiler
> Subject: RFR(S): Optimize main and post loop out when pre loop is found empty
> 
> http://cr.openjdk.java.net/~roland/8085832/webrev.00/
> 
> This is the change I proposed as a fix for 8078866.
> 
> Roland.